FuelCell Energy (FCEL) 10-K 19 Dec 23 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Oct. 31, 2023	Dec. 14, 2023	Apr. 28, 2023
Cover [Abstract]
Entity Registrant Name	FUELCELL ENERGY, INC.
Entity Central Index Key	0000886128
Document Type	10-K
Document Period End Date	Oct. 31, 2023
Current Fiscal Year End Date	--10-31
Document Transition Report	false
Amendment Flag	false
Entity File Number	1-14204
Entity Tax Identification Number	06-0853042
Entity Address, Address Line One	3 Great Pasture Road
Entity Address, City or Town	Danbury
Entity Address, State or Province	CT
Entity Incorporation, State or Country Code	DE
Entity Address, Postal Zip Code	06810
City Area Code	203
Local Phone Number	825-6000
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	FCEL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Document Annual Report	true
Entity Well-known Seasoned Issuer	Yes
ICFR Auditor Attestation Flag	true
Entity Voluntary Filers	No
Entity Public Float			$ 763,367,486
Entity Common Stock, Shares Outstanding		451,804,288
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Auditor Name	KPMG LLP
Auditor Firm ID	185
Auditor Location	Hartford, Connecticut

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Current assets:
Cash and cash equivalents, unrestricted	$ 249,952	$ 458,055
Restricted cash and cash equivalents - short-term	5,159	4,423
Investments - short-term	103,760
Accounts receivable, net	3,809	4,885
Unbilled receivables	16,296	11,019
Inventories	84,456	90,909
Other current assets	12,881	10,989
Total current assets	476,313	580,280
Restricted cash and cash equivalents - long-term	44,465	18,566
Inventories - long-term	7,329	7,549
Project assets, net	258,066	232,886
Property, plant and equipment, net	89,668	58,137
Operating lease right-of-use assets, net	8,352	7,189
Goodwill	4,075	4,075
Intangible assets, net	16,076	17,373
Other assets	51,176	13,662
Total assets (1)	955,520	939,717
Current liabilities:
Current portion of long-term debt	10,067	13,198
Current portion of operating lease liabilities	599	650
Accounts payable	26,518	28,196
Accrued liabilities	26,313	27,415
Deferred revenue	2,406	16,341
Total current liabilities	65,903	85,800
Long-term deferred revenue and customer deposits	732	9,095
Long-term operating lease liabilities	8,992	7,575
Long-term debt and other liabilities	119,588	82,863
Total liabilities (1)	195,215	185,333
Redeemable noncontrolling interest		3,030
Stockholders' equity:
Common stock ($0.0001 par value); 1,000,000,000 shares and 500,000,000 shares authorized as of October 31, 2023 and October 31, 2022; 450,626,862 and 405,562,988 shares issued and outstanding as of October 31, 2023 and October 31, 2022, respectively	45	41
Additional paid-in capital	2,199,661	2,094,076
Accumulated deficit	(1,515,541)	(1,407,973)
Accumulated other comprehensive loss	(1,672)	(1,752)
Treasury stock, Common, at cost (246,468 and 142,837 shares as of October 31, 2023 and October 31, 2022, respectively)	(1,078)	(855)
Deferred compensation	1,078	855
Total stockholder's equity	682,493	684,392
Noncontrolling interest	17,955	7,105
Total equity	700,448	691,497
Total liabilities, redeemable noncontrolling interests and stockholders' equity	955,520	939,717
Series B Preferred Stock
Current liabilities:
Redeemable Series B preferred stock (liquidation preference of $64,020 as of October 31, 2023 and October 31, 2022)	$ 59,857	$ 59,857

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,000,000,000	500,000,000
Common stock, shares issued	450,626,862	405,562,988
Common stock, shares outstanding	450,626,862	405,562,988
Treasury stock, shares	246,468	142,837
Assets	$ 955,520	$ 939,717
Cash	249,952	458,055
Accounts receivable, net	3,809	4,885
Unbilled receivables	16,296	11,019
Operating lease right-of-use assets, net	8,352	7,189
Other current assets	12,881	10,989
Restricted cash and cash equivalents - long-term	44,465	18,566
Project assets, net	$ 258,066	232,886
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other assets
Other assets	$ 51,176	13,662
Current portion of operating lease liabilities	599	650
Accounts payable	26,518	28,196
Accrued liabilities	26,313	27,415
Long-term operating lease liabilities	8,992	7,575
Other non-current liabilities	119,588	82,863
Total liabilities	195,215	185,333
Variable interest entity ("VIE")
Assets	235,290	119,223
Cash	4,797	2,149
Unbilled receivables	1,876	1,070
Operating lease right-of-use assets, net	1,680	1,184
Other current assets	50,713	14,373
Restricted cash and cash equivalents - long-term	526
Project assets, net	170,444	100,448
Derivative asset	4,127
Other assets	1,125
Current portion of operating lease liabilities	203	157
Accounts payable	165,824	76,050
Accrued liabilities		824
Long-term operating lease liabilities	2,159	1,478
Other non-current liabilities	187
Series B Preferred Stock
Preferred Stock, Liquidation Preference, Value	$ 64,020	$ 64,020

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Revenues:
Total revenues	$ 123,394	$ 130,484	$ 69,585
Costs of revenues:
Total costs of revenues	133,929	160,059	85,224
Gross loss	(10,535)	(29,575)	(15,639)
Operating expenses:
Administrative and selling expenses	64,528	79,620	37,948
Research and development expenses	61,021	34,529	11,315
Total costs and expenses	125,549	114,149	49,263
Loss from operations	(136,084)	(143,724)	(64,902)
Interest expense	(7,247)	(6,394)	(7,363)
Interest income	15,795	3,386	34
Change in fair value of common stock warrant liability			(15,974)
Extinguishment of Series 1 preferred share obligation			(934)
Gain (loss) on extinguishment of debt and finance obligations	15,337		(11,156)
Other income (expense), net	4,724	319	(728)
Loss before provision for income taxes	(107,475)	(146,413)	(101,023)
Provision for income taxes	(581)	(819)	(2)
Net loss	(108,056)	(147,232)	(101,025)
Net (loss) income attributable to noncontrolling interest	(488)	(4,510)	30
Net loss attributable to FuelCell Energy, Inc.	(107,568)	(142,722)	(101,055)
Series B preferred stock dividends	(3,200)	(3,200)	(3,200)
Net loss attributable to common stockholders	$ (110,768)	$ (145,922)	$ (104,255)
Loss per share basic and diluted:
Net loss per share attributable to common stockholders, basic	$ (0.26)	$ (0.38)	$ (0.31)
Net loss per share attributable to common stockholders, diluted	$ (0.26)	$ (0.38)	$ (0.31)
Basic weighted average shares outstanding	419,747,796	383,139,140	334,742,346
Diluted weighted average shares outstanding	419,747,796	383,139,140	334,742,346
Net loss	$ (108,056)	$ (147,232)	$ (101,025)
Other comprehensive income (loss):
Foreign currency translation adjustments	80	(933)	(80)
Total comprehensive loss	(107,976)	(148,165)	(101,105)
Comprehensive (loss) income attributable to noncontrolling interest	(488)	(4,510)	30
Comprehensive loss attributable to FuelCell Energy, Inc.	(107,488)	(143,655)	(101,135)
Series B Preferred Stock
Operating expenses:
Series B preferred stock dividends	(3,200)	(3,200)	(3,200)
Product
Revenues:
Total revenues	19,589	60,000
Costs of revenues:
Total costs of revenues	12,878	64,495	7,976
Service and License
Revenues:
Total revenues	49,084	12,786	19,791
Costs of revenues:
Total costs of revenues	44,953	17,233	24,735
Generation
Revenues:
Total revenues	37,508	36,186	24,027
Costs of revenues:
Total costs of revenues	62,913	63,147	36,017
Advanced Technologies
Revenues:
Total revenues	17,213	21,512	25,767
Costs of revenues:
Total costs of revenues	$ 13,185	$ 15,184	$ 16,496

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total Stockholder's Equity [Member]	Common Stock	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Deferred Compensation [Member]	Noncontrolling Interests [Member]	Series B Preferred Stock	Total
Beginning Balance at Oct. 31, 2020	$ 194,548	$ 29	$ 1,359,454	$ (1,164,196)	$ (739)	$ (432)	$ 432			$ 194,548
Beginning Balance at (in shares) at Oct. 31, 2020		294,706,758
Sale of common stock, net of fees	525,895	$ 8	525,887							525,895
Sale of common stock, net of fees (in shares)		69,074,573
Orion warrant exercises and other warrant exercises	22,093		22,093							22,093
Orion warrant exercises and other warrant exercises (in shares)		2,714,026
Common stock issued, non-employee compensation	275		275							$ 275
Common stock issued, non-employee compensation (in shares)		31,889								31,889
Share based compensation	4,293		4,293							$ 4,293
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards	(331)		(331)							(331)
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards (in shares)		108,511
Preferred dividends - Series B	(3,200)		(3,200)						$ (3,200)	(3,200)
Effect of foreign currency translation	80				80					80
Adjustment for deferred compensation						(154)	154
Adjustment for deferred compensation (in shares)		(17,019)
Release of a share reserve		(45)
Net loss attributable to noncontrolling interests										(30)
Net loss attributable to FuelCell Energy, Inc.	(101,055)			(101,055)						(101,055)
Net loss										(101,025)
Ending Balance at Oct. 31, 2021	642,438	$ 37	1,908,471	(1,265,251)	(819)	(586)	586			642,438
Ending Balance at (in shares) at Oct. 31, 2021		366,618,693
Sale of common stock, net of fees	183,552	$ 4	183,548							183,552
Sale of common stock, net of fees (in shares)		38,396,904
Common stock issued, non-employee compensation	305		305							$ 305
Common stock issued, non-employee compensation (in shares)		76,848								76,848
Share based compensation	6,792		6,792							$ 6,792
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards	(1,840)		(1,840)							(1,840)
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards (in shares)		539,950
Preferred dividends - Series B	(3,200)		(3,200)						(3,200)	(3,200)
Effect of foreign currency translation	933				933					933
Adjustment for deferred compensation						(269)	269
Adjustment for deferred compensation (in shares)		(69,407)
Reclassification of noncontrolling interest								$ 12,419		12,419
Return of capital to noncontrolling interest								(496)		(496)
Distribution to noncontrolling interest								(308)		(308)
Net loss attributable to noncontrolling interests	4,510			4,510				(4,510)		4,510
Net loss attributable to FuelCell Energy, Inc.										(142,722)
Net loss	(147,232)			(147,232)						(147,232)
Ending Balance at Oct. 31, 2022	684,392	$ 41	2,094,076	(1,407,973)	(1,752)	(855)	855	7,105		$ 691,497
Ending Balance at (in shares) at Oct. 31, 2022		405,562,988								405,562,988
Sale of common stock, net of fees	97,439	$ 4	97,435							$ 97,439
Sale of common stock, net of fees (in shares)		44,320,825
Common stock issued, non-employee compensation	225		225							$ 225
Common stock issued, non-employee compensation (in shares)		103,631								103,631
Share based compensation	11,954		11,954							$ 11,954
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards	(829)		(829)							(829)
Stock issued under benefit plans, net of taxes paid upon vesting of restricted stock awards (in shares)		743,049
Preferred dividends - Series B	(3,200)		(3,200)						$ (3,200)	(3,200)
Effect of foreign currency translation	(80)				(80)					(80)
Adjustment for deferred compensation						(223)	223
Adjustment for deferred compensation (in shares)		(103,631)
Contributions received for the sale of noncontrolling interest								9,052		9,052
Reclassification of noncontrolling interest								3,030		3,030
Distribution to noncontrolling interest								(744)		(744)
Net loss attributable to noncontrolling interests	488			488				(488)		488
Net loss attributable to FuelCell Energy, Inc.										(107,568)
Net loss	(108,056)			(108,056)						(108,056)
Ending Balance at Oct. 31, 2023	$ 682,493	$ 45	$ 2,199,661	$ (1,515,541)	$ (1,672)	$ (1,078)	$ 1,078	$ 17,955		$ 700,448
Ending Balance at (in shares) at Oct. 31, 2023		450,626,862								450,626,862

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Cash flows from operating activities:
Net loss	$ (108,056)	$ (147,232)	$ (101,025)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	11,954	6,792	4,293
Depreciation and amortization	25,375	21,274	19,872
Change in fair value of common stock warrant liability			15,974
Gain on Series 1 preferred stock extinguishment			934
Non-cash interest expense on preferred stock and debt and finance obligations	3,228	4,210	4,438
(Gain) loss on extinguishment of debt and finance obligations	(15,337)		11,156
Unrealized gain on derivative asset	(7,441)	(779)	(478)
Operating lease costs	1,486	1,521	1,545
Operating lease payments	(1,226)	(1,438)	(1,226)
Impairment of property, plant and equipment and project assets	2,375	1,782	5,024
Unrealized foreign currency (gains) losses	(57)	583
Other, net	456	2,632	996
Decrease (increase) in operating assets:
Accounts receivable	1,076	9,199	(5,167)
Unbilled receivables	(21,921)	(231)	(3,609)
Inventories	4,686	(28,058)	(18,755)
Other assets	(13,090)	(2,092)	(1,529)
Increase (decrease) in operating liabilities:
Accounts payable	3,001	6,332	1,988
Accrued liabilities	(4,461)	24,616	317
Deferred revenue	(22,298)	(11,278)	(5,186)
Net cash used in operating activities	(140,250)	(112,167)	(70,438)
Cash flows from investing activities:
Capital expenditures	(39,355)	(21,078)	(6,353)
Project asset expenditures	(53,007)	(25,573)	(66,877)
Maturity of held-to-maturity debt securities	199,090
Purchases of held-to-maturity debt securities	(299,093)
Net cash used in investing activities	(192,365)	(46,651)	(73,230)
Cash flows from financing activities:
Repayment of debt	(47,830)	(9,544)	(98,642)
Proceeds from the issuance of debt	100,500		10,175
Common stock issued for stock plans and related expenses	56	47	18
Contributions received from sale of noncontrolling interest, net of return of capital	9,052	11,923	3,000
Distribution to noncontrolling interests	(596)	(308)
Payments for taxes related to net share settlement of equity awards	(885)	(1,887)	(339)
Payment for early extinguishment of debt			(4,000)
Payment of deferred financing costs	(3,469)		(363)
Repayment of Series 1 preferred stock obligation			(21,541)
Proceeds from sale of common stock and warrant exercises, net of fees	97,439	183,552	526,800
Payment of preferred dividends	(3,200)	(3,200)	(3,200)
Net cash provided by financing activities	151,067	180,583	411,908
Effects on cash from changes in foreign currency rates	80	(933)	(80)
Net (decrease) increase in cash, cash equivalents and restricted cash	(181,468)	20,832	268,160
Cash, cash equivalents and restricted cash-beginning of period	481,044	460,212	192,052
Cash, cash equivalents and restricted cash-end of period	$ 299,576	$ 481,044	$ 460,212

Nature of Business, Basis of Pr

Nature of Business, Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Oct. 31, 2023
Nature of Business and Basis of Presentation
Nature of Business, Basis of Presentation and Significant Accounting Policies	Note 1. Nature of Business, Basis of Presentation and Significant Accounting Policies Nature of Business and Basis of Presentation Headquartered in Danbury, Connecticut, FuelCell Energy, Inc. (together with its subsidiaries, the “Company” “FuelCell Energy,” “we,” “us,” or “our”) is a global leader in delivering environmentally responsible distributed baseload energy platform solutions through our proprietary fuel cell technology. Today, we offer commercial technology that produces clean electricity, heat, clean hydrogen, and water and is also capable of recovering and capturing carbon for utilization and/or sequestration, depending on product configuration and application. We also continue to invest in product development and commercializing technologies that are expected to add new capabilities to our platforms’ abilities to deliver hydrogen and long duration hydrogen-based energy storage through our solid oxide technologies, as well as further enhance our existing platforms’ carbon capture solutions. ​ FuelCell Energy is focused on advancing sustainable clean energy technologies that address some of the world’s most critical challenges around energy access, security, resilience, reliability, affordability, safety and environmental stewardship. As a leading global manufacturer of proprietary fuel cell technology platforms, FuelCell Energy is uniquely positioned to serve customers worldwide with sustainable products and solutions for industrial and commercial businesses, utilities, governments, municipalities, and communities. ​ The consolidated financial statements include our accounts, those of our wholly-owned subsidiaries, and those of our consolidated variable interest entities. All intercompany accounts and transactions have been eliminated. Certain reclassifications have been made to the prior year amounts to conform to the presentation for the year ended October 31, 2023. Interest income for the years ended October 31, 2022 and 2021, which was previously included within Other income (expense), net has been reclassified to Interest income in the Consolidated Statements of Operations and Comprehensive Loss. ​ Liquidity Our principal sources of cash have been proceeds from the sale of our products and projects, electricity generation revenues, research and development and service agreements with third parties, sales of our common stock through public equity offerings, and proceeds from debt, project financing and tax monetization transactions. We have utilized this cash to accelerate the commercialization of our solid oxide platforms, develop new capabilities to separate and capture carbon, develop and construct project assets, invest in capital improvements and expansion of our operations, perform research and development, pay down existing outstanding indebtedness, and meet our other cash and liquidity needs. As of October 31, 2023, unrestricted cash and cash equivalents totaled $250.0 million compared to $458.1 million as of October 31, 2022. During the year ended October 31, 2023, the Company invested in United States (U.S.) Treasury Securities. The amortized cost of the U.S. Treasury Securities outstanding totaled $103.8 million as of October 31, 2023 compared to $0 as of October 31, 2022 and is classified as Investments - short-term on the Consolidated Balance Sheets. The maturity dates for the outstanding U.S. Treasury Securities range from November 9, 2023 to January 23, 2024. The Company, from time to time, offers and sells shares under its Open Market Sale Agreement (as defined in Note 12. “Stockholders’ Equity and Warrant Liabilities”). During the fiscal year ended October 31, 2023, approximately 44.3 million shares were sold under the Open Market Sale Agreement resulting in gross proceeds of approximately $99.7 million. See Note 12. “Stockholders’ Equity and Warrant Liabilities” for additional information regarding the Open Market Sale Agreement. ​ During the third quarter of fiscal year 2023, the Company (through one of its indirect subsidiaries) entered into a project financing facility (which is referred to as the “OpCo Financing Facility”) in the amount of $80.5 million, which was partially used to extinguish certain existing debt, to partially repay other existing debt, and to repurchase project assets under sale-leaseback transactions, resulting in $46.1 million of net proceeds. See Note 11. “Debt” for additional information regarding the OpCo Financing Facility. ​ During the fourth quarter of fiscal year 2023, the Company (through one of its indirect subsidiaries) entered into two related term loan facilities (which are referred to herein as the “Senior Back Leverage Loan Facility” and the “Subordinated Back Leverage Loan Facility”) in the aggregate amount of $20.0 million. See Note 11. “Debt” for additional information regarding the Senior Back Leverage Loan Facility and the Subordinated Back Leverage Loan Facility . ​ During the fourth quarter of fiscal year 2023, the Company closed on a tax equity financing transaction with Franklin Park 2023 FCE Tax Equity Fund, LLC (“Franklin Park”), a subsidiary of Franklin Park Infrastructure, LLC, for two fuel cell power plant installations -- the 14.0 MW Derby Fuel Cell Project and the 2.8 MW SCEF Fuel Cell Project, both located in Derby, Connecticut (collectively the “Derby Projects”). Franklin Park’s tax equity commitment with respect to the Derby Projects totals $30.2 million. Of this amount, approximately $9.1 million was received on October 31, 2023. In connection with the closing of this tax equity financing transaction, the Company paid closing costs of approximately $1.8 million, which included appraisal fees, title insurance expenses and legal and consulting fees. The balance of this commitment will be funded to the Company upon substantial completion of the Derby Projects. Net of estimated additional fees of $0.5 million, the Company anticipates additional funding of approximately $20.6 million. We believe that our unrestricted cash and cash equivalents, expected receipts from our contracted backlog, funds received upon the maturity of U.S. Treasury Securities, and release of short-term restricted cash less expected disbursements over the next twelve months will be sufficient to allow the Company to meet its obligations for at least one year from the date of issuance of these financial statements. ​ To date, we have not achieved profitable operations or sustained positive cash flow from operations. The Company’s future liquidity, for fiscal year 2024 and in the long-term, will depend on its ability to (i) timely complete current projects in process within budget, (ii) increase cash flows from its generation operating portfolio, including by meeting conditions required to timely commence operation of new projects, operating its generation operating portfolio in compliance with minimum performance guarantees and operating its generation operating portfolio in accordance with revenue expectations, (iii) obtain financing for project construction and manufacturing expansion, (iv) obtain permanent financing for its projects once constructed, (v) increase order and contract volumes, which would lead to additional product sales, service agreements and generation revenues, (vi) obtain funding for and receive payment for research and development under current and future Advanced Technologies contracts, (vii) successfully commercialize its solid oxide, hydrogen and carbon capture platforms, (viii) implement capacity expansion for solid oxide product manufacturing, (ix) implement the product cost reductions necessary to achieve profitable operations, (x) manage working capital and the Company’s unrestricted cash balance and (xi) access the capital markets to raise funds through the sale of debt and equity securities, convertible notes, and other equity-linked instruments. We are continually assessing different means by which to accelerate the Company’s growth, enter new markets, commercialize new products, and enable capacity expansion. Therefore, from time to time, the Company may consider and enter into agreements for one or more of the following: negotiated financial transactions, minority investments, collaborative ventures, technology sharing, transfer or other technology license arrangements, joint ventures, partnerships, acquisitions or other business transactions for the purpose(s) of geographic or manufacturing expansion and/or new product or technology development and commercialization, including hydrogen production through our carbonate and solid oxide platforms and storage and carbon capture, sequestration and utilization technologies. Our business model requires substantial outside financing arrangements and satisfaction of the conditions of such arrangements to construct and deploy our projects to facilitate the growth of our business. The Company has invested capital raised from sales of its common stock to build out its project portfolio. The Company has also utilized and expects to continue to utilize a combination of long-term debt and tax equity financing (e.g., sale-leaseback transactions, partnership flip transactions and the monetization and/or transfer of eligible investment and production tax credits) to finance its project asset portfolio as these projects commence commercial operations, particularly in light of the passage of the Inflation Reduction Act in August 2022. The Company may also seek to undertake private placements of debt securities to finance its project asset portfolio. The proceeds of any such financing, if obtained, may allow the Company to reinvest capital back into the business and to fund other projects. We may also seek to obtain additional financing in both the debt and equity markets in the future. If financing is not available to us on acceptable terms if and when needed, or on terms acceptable to us or our lenders, if we do not satisfy the conditions of our financing arrangements, if we spend more than the financing approved for projects, if project costs exceed an amount that the Company can finance, or if we do not generate sufficient revenues or obtain capital sufficient for our corporate needs, we may be required to reduce or slow planned spending, reduce staffing, sell assets, seek alternative financing and take other measures, any of which could have a material adverse effect on our financial condition and operations . Summary of Significant Accounting Policies Cash and Cash Equivalents All cash equivalents consist of investments in money market funds with original maturities of three months or less at the date of acquisition. We place our temporary cash equivalent investments with high credit quality financial institutions. Inventories and Advance Payments to Vendors Inventories consist principally of raw materials and work-in-process. Cost is determined using the first-in, first-out cost method. Included in our inventory balance are used modules that are brought back into inventory upon installation of new modules. When a new module is installed, a determination is made as to whether the used module has remaining useful life or should be scrapped and materials recycled. Modules that are deemed to have remaining useful life are put into inventory at an estimated value based on the expected remaining life of the module and its projected output. In certain circumstances, we will make advance payments to vendors for future inventory deliveries. These advance payments are recorded as Other current assets on the Consolidated Balance Sheets. Inventories are reviewed to determine net realizable value. This review includes analyzing inventory levels of individual parts considering the current design of our products and production requirements as well as the expected inventory requirements for maintenance on installed power platforms. Investments – Short-Term The Company invests in U.S. Treasury Securities which are held-to-maturity and are recorded at amortized cost. Allowance for Doubtful Accounts and Credit Losses The Company had no allowance for doubtful accounts or credit losses as of October 31, 2023 and 2022. Uncollectible accounts receivable are charged against the allowance for doubtful accounts when all collection efforts have failed and it is deemed unlikely that the amount will be recovered. The Company would record a specific reserve for individual accounts when the Company becomes aware of specific customer circumstances such as in the case of a bankruptcy filing or the deterioration in the customer’s operating results or financial position. Project Assets Project assets consist of capitalized costs for fuel cell projects in various stages of development, including those projects with respect to which we have entered into power purchase agreements (“PPAs”) and those projects with respect to which we expect to secure long-term contracts. Such development costs are generally incurred prior to entering into a definitive sales or long-term financing agreement for the project. Project assets also include capitalized costs for fuel cell projects which are the subject of sale-leaseback transactions with Crestmark Equipment Finance, a division of MetaBank (“Crestmark”). Project asset costs include costs for developing and constructing a complete turn-key fuel cell project. Development costs can include legal, consulting, permitting, interconnect, and other similar costs. To the extent we enter into a definitive sales agreement, we expense project assets to cost of sales after the respective project asset is sold to a customer and all revenue recognition criteria have been met. Property, Plant and Equipment Property, plant and equipment are stated at cost, less accumulated depreciation which is recorded based on the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are amortized on the straight-line method over the shorter of the estimated useful lives of the assets or the term of the lease. When property, plant or equipment is sold or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in operations for the period. Goodwill and Indefinite-Lived Intangibles Goodwill represents the excess of the aggregate purchase price over the fair value of the net assets acquired in a business combination and is reviewed for impairment at least annually. The intangible asset represents indefinite-lived in-process research and development (“IPR&D”) for cumulative research and development efforts associated with the development of solid oxide fuel cell stationary power generation and is also reviewed at least annually for impairment. Accounting Standards Codification (“ASC”) Topic 350: Intangibles - Goodwill and Other The Company completed its annual impairment analysis of goodwill and IPR&D as of July 31, 2023. The goodwill and IPR&D asset are both held by the Company’s Versa Power Systems, Inc. (“Versa Inc.”) reporting unit. Goodwill and the IPR&D asset are also reviewed for possible impairment whenever changes in conditions indicate that the fair value of a reporting unit or IPR&D asset is more likely than not below its respective carrying value. No impairment charges were recorded with respect to goodwill or the IPR&D asset during the fiscal years ended October 31, 2023, 2022 and 2021. Impairment of Long-Lived Assets (including Project Assets) Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. If events or changes in circumstances indicate that the carrying amount of the asset group may not be recoverable, we compare the carrying amount of the asset group to the future undiscounted net cash flows, excluding debt service costs, expected to be generated by the asset group and its ultimate disposition. If the sum of the undiscounted cash flows is less than the carrying value, the impairment to be recognized is measured by the amount by which the carrying amount of the asset group exceeds its fair value. Revenue Recognition The Company recognizes revenue in accordance with ASC Topic 606: Revenue from Contracts with Customers A contract is accounted for when there has been approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Performance obligations under a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. In certain instances, the Company has concluded distinct goods or services should be accounted for as a single performance obligation that is a series of distinct goods or services that have the same pattern of transfer to the customer. To the extent a contract includes multiple promised goods or services, the Company must apply judgment to determine whether the customer can benefit from the goods or services either on their own or together with other resources that are readily available to the customer (the goods or services are capable of being distinct) and if the promise to transfer the goods or services to the customer is separately identifiable from other promises in the contract (the goods or services are distinct in the context of the contract). If these criteria are not met, the promised goods or services are accounted for as a single performance obligation. The transaction price is determined based on the consideration that the Company will be entitled to in exchange for transferring goods or services to the customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price, generally utilizing the expected value method. Determining the transaction price requires judgment. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price basis. Standalone selling price is determined by the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price by taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. Performance obligations are satisfied either over time or at a point in time as discussed in further detail below. In addition, the Company’s contracts with customers generally do not include significant financing components or non-cash consideration. The Company has elected practical expedients in the accounting guidance that allow for revenue to be recorded in the amount that the Company has a right to invoice, if that amount corresponds directly with the value to the customer of the Company’s performance to date, and that allow the Company not to disclose related unsatisfied performance obligations. The Company records any amounts that are billed to customers in excess of revenue recognized as deferred revenue and revenue recognized in excess of amounts billed to customers as unbilled receivables. Revenue streams are classified as follows: Product. Service. Generation. Advanced Technologies. See below for a discussion of revenue recognition under ASC 606 by disaggregated revenue stream. Completed project assets Contracts for the sale of completed project assets include the sale of the project asset, the assignment of the service agreement, and the assignment of the PPA. The relative stand-alone selling price is estimated and is used as the basis for allocation of the contract consideration. Revenue is recognized upon the satisfaction of the performance obligations, which includes the transfer of control of the project asset to the customer, which is when the contract is signed and the PPA is assigned to the customer. See below for further discussion regarding revenue recognition for service agreements. Contractual payments related to the sale of the project asset and assignment of the PPA are generally received up-front. Payment terms for service agreements are generally ratable over the term of the agreement. Module sales Contracts for module sales represent the sale of a completed fuel cell module at a contracted selling price. These contracts are on a per unit basis and revenue is recognized as each unit is completed and ready to ship and the performance obligation is satisfied. Payment terms for module sales are generally based on milestones achieved through the manufacturing timeline of the module. Service agreements Service agreements represent a single performance obligation whereby the Company performs all required maintenance and monitoring functions, including replacement of modules, to ensure the power platform(s) under the service agreement generate a minimum power output. To the extent the power platform(s) under service agreements do not achieve the minimum power output, certain service agreements include a performance guarantee penalty. Performance guarantee penalties represent variable consideration, which is estimated for each service agreement based on past experience, using the expected value method. The consideration for each service agreement is recognized over time using costs incurred to date relative to total estimated costs at completion to measure progress. The Company reviews its cost estimates on service agreements on an annual basis and records any changes in estimates on a cumulative catch-up basis. Loss accruals for service agreements are recognized to the extent that the estimated remaining costs to satisfy the performance obligation exceed the estimated remaining unrecognized consideration. Estimated losses are recognized in the period in which losses are identified. Payment terms for service agreements are generally ratable over the term of the agreement. Advanced Technologies contracts Advanced Technologies contracts include the promise to perform research and development services and, as such, this represents one performance obligation. Revenue from most government sponsored Advanced Technologies projects is recognized as direct costs are incurred plus allowable overhead less cost share requirements, if any. Revenue is only recognized to the extent the contracts are funded. Revenue recognition for research performed under the EMTEC Joint Development Agreement (as defined elsewhere herein) falls into the practical expedient category where revenue is recorded consistent with the amounts the Company has the right to invoice. Payments are based on costs incurred for government sponsored Advanced Technologies projects and payments under the EMTEC Joint Development Agreement are based on contractual rates for time spent and material costs incurred. Generation revenue For certain project assets where customers purchase electricity from the Company under PPAs, the Company has determined that these agreements should be accounted for as operating leases pursuant to ASC 842, Leases Variable Interest Entities and Noncontrolling Interests The Company has entered into tax equity financing transactions with certain participating companies for three partnerships (as further described in Note 3. “Tax Equity Financings and Investment Tax Credit Sale”) as of October 31, 2023. These transactions are structured as “partnership flips.” A “partnership flip” is a structure commonly used by tax equity investors in financing renewable energy projects. The Company has determined, under the power and benefits criterion of ASC 810, Consolidations ​ Sale-Leaseback Accounting The Company, through certain wholly-owned subsidiaries, has entered into sale-leaseback transactions for commissioned project assets where we have entered into a PPA with a customer who is both the site host and end user of the power. Due to the Company not meeting criteria to account for the transfer of the project assets as a sale since the leases include a repurchase right, sale accounting is precluded. Accordingly, the Company uses the financing method to account for these transactions. Under the financing method of accounting for a sale-leaseback, the Company does not derecognize the project assets and does not recognize as revenue any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as finance obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the finance obligation. Interest on the finance obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding finance obligation. While we receive financing for the related project asset, we have not recognized revenue on the sale-leaseback transactions. Instead, revenue is recognized with respect to the related PPAs in accordance with the Company’s accounting policies for recognizing generation revenue. ​ Lease Accounting Right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the present value of the Company’s obligation to make lease payments arising from the lease over the lease term at the commencement date of the lease. As most of the Company’s leases do not provide an implicit rate, the Company estimated the incremental borrowing rate based on the information available at the date of adoption in determining the present value of lease payments and used the implicit rate when readily determinable. The Company determined incremental borrowing rates through market sources for secured borrowings including relevant industry rates. The Company’s operating lease ROU assets also include any lease pre-payments and exclude lease incentives. Certain of the Company’s leases include variable payments, which may vary based upon changes in facts or circumstances after the start of the lease. The Company excludes variable payments from lease ROU assets and lease liabilities to the extent not considered in-substance fixed, and instead, expenses variable payments as incurred. Variable lease expense and lease expense for short term contracts are not material components of lease expense. The Company’s leases generally have remaining lease terms of 1 to 26 years, some of which include options to extend leases. The exercise of lease renewal options is at the Company’s sole discretion and the Company’s lease ROU assets and liabilities reflect only the options the Company is reasonably certain that it will exercise. We do not have leases with residual value guarantees or similar covenants. Service Expense Recognition We warranty our products for a specific period of time against manufacturing or performance defects. Our U.S. warranty is generally limited to a term of 15 months after shipment or 12 months after acceptance of our products. We accrue for estimated future warranty costs based on historical experience. We also provide for a specific accrual if there is a known issue requiring repair during the warranty period. In addition to the standard product warranty, we have entered into service agreements with certain customers to provide monitoring, maintenance and repair services for fuel cell power platforms. Under the terms of these service agreements, the power platform must meet a minimum operating output during the term. If the minimum output falls below the contract requirement, we may be subject to performance penalties or may be required to repair and/or replace the customer’s fuel cell module(s). The Company records loss accruals for service agreements when the estimated cost of future module exchanges and maintenance and monitoring activities exceeds the remaining unrecognized contract value. Estimates for future costs on service agreements are determined by a number of factors, including the estimated remaining life of the module(s), used replacement modules available and future operating plans for the power platform. Our estimates are performed on a contract by contract basis and include cost assumptions based on what we anticipate the service requirements will be to fulfill obligations for each contract. At the end of our service agreements, customers are expected to either renew the service agreement or, based on the Company’s rights to title of the module, the module will be returned to the Company as the platform is no longer being maintained. Research and Development Costs We perform both customer-sponsored research and development projects based on contractual agreements with customers and company-sponsored research and development projects. Costs incurred for customer-sponsored projects include manufacturing and engineering labor, applicable overhead expenses, materials to build and test prototype units and other costs associated with customer-sponsored research and development contracts. Costs incurred for customer-sponsored projects are recorded as cost of Advanced Technologies contract revenues in the Consolidated Statements of Operations and Comprehensive Loss. Costs incurred for company-sponsored research and development projects consist primarily of labor, overhead, materials to build and test prototype units and consulting fees. These costs are recorded as research and development expenses in the Consolidated Statements of Operations and Comprehensive Loss. Concentrations We contract with a concentrated number of customers for the sale of our products, for service agreements, for power purchase agreements and for Advanced Technologies contracts. For the years ended October 31, 2023, 2022 and 2021, our top customers accounted for 68%, 74% and 61%, respectively, of our total annual consolidated revenue. The percent of consolidated revenues from our top customers for the years ended October 31, 2023, 2022 and 2021, respectively, are presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 Korea Southern Power Company (KOSPO) 31 % 6 % 12 % Korea Fuel Cell Co., Ltd (KFC) ​ 16 % 46 % — % Connecticut Light and Power 13 % 14 % 20 % ExxonMobil Technology and Engineering Company (f/k/a ExxonMobil Research and Engineering Company) (EMTEC) 8 % 8 % 29 % Total 68 % 74 % 61 % ​ Derivatives ​ We do not use derivatives for speculative or trading purposes. The Company has an interest rate swap that is adjusted to fair value on a quarterly basis. The estimated fair value is based on Level 2 inputs including primarily the floating Secured Overnight Financing Rate (“SOFR”) rate available to swap dealers. The valuation methodology involves comparison of (i) the sum of the present value of all quarterly variable rate payments based on a reset rate using the floating SOFR curve and (ii) the sum of the present value of all quarterly fixed rate payments on the notional amount, which is equivalent to the outstanding principal amount of the loan. ​ The Company has recorded a natural gas purchase contract at fair value which was the result of the net settling of certain natural gas purchases under a contract that was previously designated as normal purchase normal sale which resulted in a change to mark-to-market accounting. The fair value will be adjusted on a quarterly basis. The estimated fair value is based on Level 2 inputs including future prices available to commodity brokers and risk-free rates which are based on Federal reserve yields. The valuation methodology involves utilizing the industry-convention energy swap model. ​ Use of Estimates The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the U.S. (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Estimates are used in accounting for, among other things, revenue recognition, lease right-of-use assets and liabilities, excess, slow-moving and obsolete inventories, product warranty accruals, loss accruals on service agreements, share-based compensation expense, allowance for doubtful accounts, depreciation and amortization, impairment of goodwill and in-process research and d

Revenue Recognition

Revenue Recognition	12 Months Ended
	Oct. 31, 2023
Revenue Recognition
Revenue Recognition	Note 2. Revenue Recognition Contract Balances Contract assets as of October 31, 2023 and 2022 were $42.1 million ($25.8 million long-term) and $20.7 million ($9.7 million long-term), respectively. The contract assets relate to the Company’s rights to consideration for work completed but not yet billed. These amounts are included on a separate line item as Unbilled receivables, and balances expected to be billed later than one year from the balance sheet date are included within Other assets on the accompanying Consolidated Balance Sheets. We bill customers for power platform and power platform component sales based on certain contractual milestones being reached. We bill service agreements based on the contract price and billing terms of the contracts. Generally, our Advanced Technologies contracts are billed based on actual revenues recorded, typically in the subsequent month. Some Advanced Technologies contracts are billed based on contractual milestones or costs incurred. The net change in contract assets represents amounts recognized as revenue offset by customer billings. For the years ended October 31, 2023 and 2022, a total of $12.9 million and $5.3 million, respectively, was transferred to accounts receivable from contract assets recognized at the beginning of the period. Contract liabilities as of October 31, 2023 and 2022 were $3.1 million and $25.4 million, respectively. The contract liabilities relate to the advance billings to customers for services that will be recognized over time and in some instances for deferred revenue relating to variable consideration for previously sold products. The net change in contract liabilities represents customer billings offset by revenue recognized. Consideration Payable to a Customer As of October 31, 2023, the Company has recorded $6.3 million ($6.0 million long-term) as consideration payable to a customer which is included within Other current assets and Other assets on the accompanying Consolidated Balance Sheets. The Company received payment for the sale of an investment tax credit during the year ended October 31, 2023 and the net amount of $6.3 million will be recorded as a reduction to revenue during the period of measurement. Contract modification ​ As a result of the settlement reached with POSCO Energy Co., Ltd. (“POSCO Energy”), the Company evaluated its various license agreements with POSCO Energy as well as all of the terms of the settlement agreement with POSCO Energy, which was effective December 20, 2021 (the “Settlement Agreement”). As part of this analysis, the Company considered the accounting surrounding the execution of the Settlement Agreement, reviewed all elements related to its license agreements with POSCO Energy and the Settlement Agreement and considered any potential contingencies in these license agreements and whether any proceeds were related to the litigation settlement. ​ Under the terms of the Settlement Agreement, the Company agreed that its license agreements with POSCO Energy were not terminated, but instead were deemed to be amended such that POSCO Energy and its subsidiary, Korea Fuel Cell Co., Ltd. (“KFC”, and with POSCO Energy, collectively, “PE Group”), only have the right (i) to provide maintenance and repair services to PE Group’s then existing customers on then existing molten carbonate power generation and thermal projects under long-term service agreements then in force as well as long-term service agreements that had expired and were pending renewal as of the settlement date (collectively, “Existing LTSAs”), (ii) to supply replacement modules purchased from the Company only for their existing customers for existing molten carbonate power generation and thermal projects under Existing LTSAs and (iii) to own, operate and maintain all facilities and factories solely for the purposes set forth in (i) and (ii) above (collectively, the “Right to Service License”) and further agreed to sell modules with a service warranty pursuant to a module sales agreement to be negotiated by the parties after execution of the Settlement Agreement. As such, the Company considers the execution of the Settlement Agreement to be a contract modification as it resulted in a change in both the scope and price of a contract with a customer. Therefore, the Company accounted for such modification under the contract modification guidance included within ASC 606 (Revenue from Contracts with Customers). Further, the Company noted that none of the parties to the Settlement Agreement specifically acknowledged any payment of damages or reimbursement of any costs related to the matters settled under the Settlement Agreement, which supports the conclusion that the overall settlement was a form of contract modification. Additionally, the transaction price allocated to the modified contract did not exceed the stand-alone selling prices (“SSP”) of the performance obligations under the modified contract such that there was no indication of a premium that would indicate that a portion of the transaction price related to something other than the promised goods or services. ​ The Company identified two performance obligations in the Settlement Agreement which included the sale of 20 modules and an option to purchase an additional 14 modules. The Company assessed the SSP of the modules utilizing a cost-plus margin approach to arrive at $3.0 million per module which was recognized upon transfer of control of such modules to KFC via title transfer consistent with the Company’s established revenue recognition policies. The Company is also providing a performance guarantee for up to seven years with each module to cover any annual output penalty that would need to be paid by PE Group to a customer. The Company determined that this performance guarantee represented variable consideration and estimated a value of $0.65 million per module, which resulted in accrual of $13.1 million as of October 31, 2022 upon the sale of twenty modules during the year ended October 31, 2022. A portion of this variable consideration was recognized as revenue when it was determined that there were no amounts due under the performance guarantee. In its analysis at the time of execution of the Settlement Agreement, the Company determined that it was probable that KFC would exercise its option to purchase an additional 14 modules (with a performance guarantee) beyond the firm order of 20 modules, to which it was contractually committed. KFC’s right to purchase the additional 14 modules expired without being exercised on December 31, 2022, and as a result $9.1 million was recognized as product revenue during the year ended October 31, 2023. ​ The Company signed a long-term service agreement (“LTSA”) with Noeul Green Energy Co., Ltd. (“Noeul Green Energy”) in July 2023. Under this LTSA, once the Company, KFC/Posco International Company, and Noeul Green Energy (the “LTSA Parties”) agreed to the technical transfer specifications under a Final Acceptance Test (the “FAT”) with respect to the transfer to Noeul Green Energy of 16 of the 20 modules previously sold by the Company to KFC pursuant to the Settlement Agreement, the LTSA Parties signed a document that released KFC/POSCO International Company from any obligations to service these modules, and concurrently transferred that obligation to the Company. The FAT is effective for 16 of the 20 modules sold to KFC pursuant to the Settlement Agreement, which are now used by Noeul Green Energy. Because the Company is no longer obligated to perform any service or other obligations under the Settlement Agreement with respect to the 16 modules now used by Noeul Green Energy, the Company recognized a ratable portion of the previously accrued variable consideration of $13.1 million which resulted in recognition of $10.5 million of product revenue during the year ended October 31, 2023. ​ EMTEC Joint Development Agreement ​ Effective as of October 31, 2019, the Company entered into a Joint Development Agreement (as amended, the “EMTEC Joint Development Agreement”) with ExxonMobil Technology and Engineering Company (formerly known as ExxonMobil Research and Engineering Company) (“EMTEC”), pursuant to which the Company has engaged in exclusive research and development efforts with EMTEC to evaluate and develop new and/or improved carbonate fuel cells to reduce carbon dioxide emissions from industrial and power sources, in exchange for (i) payment by EMTEC of certain fees and costs (including research costs of up to $45.0 million) as well as certain milestone-based payments, and (ii) certain licenses . In Amendment No. 1 to the EMTEC Joint Development Agreement (“Amendment No. 1”), which was executed on October 29, 2021 and effective as of October 31, 2021, the Company and EMTEC agreed, among other things, to extend the term of the EMTEC Joint Development Agreement to April 30, 2022. Amendment No. 1 allowed for the continuation of research intended to enable incorporation of design improvements to Company fuel cell design in order to support a decision to use the improvements in a potential future demonstration of the technology for capturing carbon at an ExxonMobil refinery located in Rotterdam, Netherlands (such demonstration, the “Rotterdam Project”) and provided additional time to achieve the first milestone under the EMTEC Joint Development Agreement. In a related letter agreement between the Company and EMTEC, dated as of October 28, 2021 and executed on October 29, 2021 (the “2021 Letter Agreement”), the Company agreed to invest with EMTEC in the Rotterdam Project, should EMTEC move forward with the Rotterdam Project. In the 2021 Letter Agreement, the Company agreed that, if (i) the Company achieved the first milestone under the EMTEC Joint Development Agreement (which occurred in the first quarter of fiscal year 2022, resulting in a $5.0 million payment to the Company which the Company received in the second quarter of fiscal year 2022) and (ii) EMTEC and the Company execute a contractual agreement to proceed with the Rotterdam Project, then at EMTEC’s option, the Company will either make an investment in the amount of $5.0 million in the Rotterdam Project or discount EMTEC’s purchase of the Company’s fuel cell module and detailed engineering design, as agreed to by the parties, required for the Rotterdam Project by said amount. ​ On April 29, 2022, the Company and EMTEC entered into Amendment No. 2 (“Amendment No. 2”) to the EMTEC Joint Development Agreement, which was effective as of April 30, 2022 and which increased the maximum amount of research costs to be reimbursed by EMTEC from $45.0 million to $50.0 million and further extended the term to December 31, 2022. In Amendment No. 2, the Company and EMTEC also agreed to conduct a joint market study to (a) define application opportunities, commercialization strategies, and development requirements, (b) identify partners for potential pilot/demonstration projects and (c) assess fuel cell/stack/module manufacturing scale-up and cost reduction. ​ On December 19, 2022, the Company and EMTEC entered into Amendment No. 3 (“Amendment No. 3”) to the EMTEC Joint Development Agreement, which was effective as of December 1, 2022. In Amendment No. 3, the Company and EMTEC agreed to further extend the term of the EMTEC Joint Development Agreement such that it would end on August 31, 2023 and to further increase the maximum amount of research costs to be reimbursed by EMTEC from $50.0 million to $60.0 million. Amendment No. 3 (i) allowed for continuation of research intended to enable the parties to finalize data collection in support of the project gate decision for the Rotterdam Project, (ii) allowed for the continuation of the development, engineering and mechanical derisking of the Generation 2 Technology fuel cell module prototype, and (iii) allowed for studying the manufacturing scale-up and cost reduction of a commercial Generation 2 Technology fuel cell carbon capture facility. ​ On August 25, 2023, the Company and EMTEC entered into Amendment No. 4 to the EMTEC Joint Development Agreement (“Amendment No. 4”), effective as of August 31, 2023. In Amendment No. 4, the Company and EMTEC agreed to further extend the term of the EMTEC Joint Development Agreement such that it will end on March 31, 2024 (unless terminated earlier) and to further increase the maximum amount of research costs to be reimbursed by EMTEC from $60.0 million to $67.0 million. Amendment No. 4 is intended to allow the parties the opportunity to continue (i) derisking of the Generation 2 Technology fuel cell module demonstration prototype and (ii) the joint marketing and sales efforts to inform development of a new business framework between the parties beyond the current joint development agreement structure. During the year ended October 31, 2022, the Company achieved the first technical milestone under the EMTEC Joint Development Agreement and received payment of $5.0 million. At the time, the Company did not recognize revenue in connection with this milestone achievement as a result of its agreement with EMTEC to either make a $5.0 million investment in a demonstration of a Company fuel cell module for capturing carbon at EMTEC’s purchase of the Company’s fuel cell module and detailed engineering design for the Rotterdam Project by $5.0 million, should the Company enter into a contract with EMTEC to proceed with the Rotterdam Project. ​ In May 2023, the Company entered into a second letter agreement with EMTEC, pursuant to which the parties agreed that the conditions to the Company’s agreement to invest in the Rotterdam Project were met in April 2023 and, as a result, the Company will recognize $2.5 million of the $5.0 million milestone payment received in fiscal year 2022 as revenue across future deliverables to EMTEC. Of this $2.5 million, the Company recognized revenue of $0.3 million during the year ended October 31, 2023. The other $2.5 million of the $5.0 million milestone payment received under the EMTEC Joint Development Agreement in fiscal year 2022 was applied to discount EMTEC’s purchase of the Company’s fuel cell module and detailed engineering design for the Rotterdam Project. As of October 31, 2023, EMTEC had not yet made the decision to proceed with the Rotterdam Project. ​ Remaining Performance Obligations ​ Remaining performance obligations are the aggregate amount of total contract transaction price that is unsatisfied or partially unsatisfied. As of October 31, 2023, the Company’s total remaining performance obligations were $140.8 million for service agreements, $63.9 million for a generation PPA, $15.3 million for Advanced Technologies contracts and $0 for product revenues.

Tax Equity Financings and Inves

Tax Equity Financings and Investment Tax Credit Sale	12 Months Ended
	Oct. 31, 2023
Tax Equity Financings and Investment Tax Credit Sale
Tax Equity Financings and Investment Tax Credit Sale	Note 3. Tax Equity Financings and Investment Tax Credit Sale Derby Tax Equity Financing Transaction The Company closed on a tax equity financing transaction on October 31, 2023 with Franklin Park for two fuel cell power plant installations -- the 14.0 MW Derby Fuel Cell Project and the 2.8 MW SCEF Fuel Cell Project, both located in Derby, Connecticut (collectively, the “Derby Projects”). Franklin Park’s tax equity commitment totals $30.2 million. Of this amount, approximately $9.1 million was received on October 31, 2023. In connection with the closing of this tax equity financing transaction, the Company paid closing costs of approximately $1.8 million, which included appraisal fees, title insurance expenses and legal and consulting fees. The balance of this commitment will be funded to the Company upon substantial completion of the Derby Projects. Net of estimated additional fees of $0.5 million, the Company anticipates additional funding of approximately $20.6 million. ​ This transaction was structured as a “partnership flip”, which is a structure commonly used by tax equity investors in the financing of renewable energy projects. Under this partnership flip structure, a partnership, in this case Derby Fuel Cell Holdco, LLC (the “Derby Partnership”), was organized to acquire from FuelCell Energy Finance II, LLC, a wholly-owned subsidiary of the Company, all outstanding equity interests in the Derby Projects. FuelCell Energy Finance II owns the Derby Projects and is the party to the power purchase agreements and all project agreements. At the closing of the transaction, the Derby Projects are owned by the Derby Partnership with Franklin Park, holding the Class A Units, and Fuel Cell Energy Derby Finance Holdco, LLC holding the Class B Units. Under most partnership flip structures, tax equity investors agree to receive a minimum target rate of return, typically on an after-tax basis. Prior to receiving a contractual rate of return or a date specified in the contractual arrangements, Franklin Park will receive substantially all of the non-cash value attributable to the Derby Projects, which includes accelerated depreciation and Section 48(a) investment tax credits; however, the Company will receive a majority of the cash distributions (based on the operating income of the Derby Projects), which are to be paid quarterly. After Franklin Park receives its contractual rate of return, the Company will receive approximately 95% of the cash and tax allocations. As of October 31, 2023, the Derby Projects were not operational and as a result the Company has not yet allocated profits or losses to the noncontrolling interest under the hypothetical liquidation at book value (“HLBV”) method. Groton Tax Equity Financing Transaction ​ The Company closed on a tax equity financing transaction in August 2021 with East West Bancorp, Inc. (“East West Bank”) for the 7.4 MW fuel cell project located on the U.S. Navy Submarine Base in Groton, CT (the “Groton Project”). East West Bank’s tax equity commitment totals $15 million. ​ This transaction was structured as a partnership flip. Under this partnership flip structure, a partnership, in this case Groton Station Fuel Cell Holdco, LLC (the “Groton Partnership”), was organized to acquire from FuelCell Energy Finance II, LLC, a wholly-owned subsidiary of the Company, all outstanding equity interests in Groton Station Fuel Cell, LLC (the “Groton Project Company”) which in turn owns the Groton Project and is the party to the power purchase agreement and all project agreements. At the closing of the transaction, the Groton Partnership is owned by East West Bank, holding Class A Units, and Fuel Cell Energy Finance Holdco, LLC, a subsidiary of FuelCell Energy Finance, LLC, holding Class B Units. The acquisition of the Groton Project Company by the Groton Partnership was funded in part by an initial draw from East West Bank and funds contributed downstream to the Groton Partnership by the Company. The initial closing occurred on August 4, 2021, upon the satisfaction of certain conditions precedent (including the receipt of an appraisal and confirmation that the Groton Project would be eligible for the investment tax credit under Section 48 of the Internal Revenue Code of 1986, as amended). In connection with the initial closing, the Company drew down $3.0 million, of which approximately $0.8 million was used to pay closing costs including appraisal fees, title insurance expenses and legal and consulting fees. Under the original terms of the Company’s agreement with East West Bank, the Company would have been eligible to draw the remaining amount of the commitment, approximately $12 million, once the Groton Project achieved commercial operations. In addition, under the original terms of the Company’s agreement with East West Bank, the Groton Project had a required commercial operations deadline of October 18, 2021. The significance of the commercial operations deadline is that, if commercial operations were not achieved by such deadline, East West Bank would have the option to require an amount equal to 101% of its investment to be returned. East West Bank granted several extensions of the commercial operations deadline, which collectively extended the deadline to May 15, 2022, in exchange for the Company’s agreement to pay fees of $0.4 million in the aggregate ​ On July 7, 2022, the Company and East West Bank amended their tax equity financing agreement and extended the commercial operations deadline to September 30, 2022. In addition, in the July 7, 2022 amendment to the tax equity financing agreement, the terms of East West Bank’s remaining investment commitment of $12.0 million were modified such that East West Bank will contribute $4.0 million on each of the first second third ​ On October 4, 2022, the Company and East West Bank further amended their tax equity financing agreement to extend the deadline by which commercial operations were to be achieved at the Groton Project from September 30, 2022 to November 30, 2022. In addition, modifications to the Groton Project documents between Connecticut Municipal Electric Energy Cooperative (“CMEEC”) and the Company as a result of the agreement between those parties to commence operations at less than 7.4 MW required the approval of East West Bank as part of East West Bank’s rights under the agreement between East West Bank and the Company. On December 16, 2022, the Company and CMEEC agreed that, for all purposes, the commercial operations date has occurred, and, accordingly, East West Bank no longer had a right to have its investment returned as a result of the Company’s failure to achieve commercial operations in a timely fashion, and this investment became a non-redeemable noncontrolling interest as of December 16, 2022. In addition, on December 16, 2022, the Company paid the aggregate fees of $0.5 million described above to East West Bank. ​ On December 16, 2022, the Company declared and, per the terms of the Amended and Restated Power Purchase Agreement between the Company and CMEEC entered into on that date (the “Amended and Restated PPA”), CMEEC agreed that the Groton Project is commercially operational at 6.0 MW. As of December 16, 2022, the Groton Project is reported as a part of the Company’s generation operating portfolio. The Amended and Restated PPA allows the Company to operate the plants at a reduced output of approximately 6.0 MW while a Technical Improvement Plan (“TIP”) is implemented with the goal of bringing the platform to its rated capacity of 7.4 MW by December 31, 2023. In conjunction with entering into the Amended and Restated PPA, the Navy also provided its authorization to proceed with commercial operations at 6.0 MW. The Company paid CMEEC an amendment fee of $1.2 million and is incurring and will continue to incur performance guarantee fees under the Amended and Restated PPA as a result of operating at an output below 7.4 MW during implementation of the TIP. Although the Company believes it will successfully implement the TIP and bring the plants up to their nominal output of 7.4 MW by December 31, 2023, no assurance can be provided that such work will be successful. In the event that the plants do not reach an output of 7.4 MW by December 31, 2023, the Amended and Restated PPA will continue in effect, and the Company will be subject to ongoing performance guarantee fees as set forth in the Amended and Restated PPA. ​ With the declaration of commercial operations, East West Bank’s investment in the project was reclassified, as of December 16, 2022, from a redeemable noncontrolling interest to non-redeemable noncontrolling interests within the Total equity section of the Consolidated Balance Sheets. ​ Under most partnership flip structures, tax equity investors agree to receive a minimum target rate of return, typically on an after-tax basis. Prior to receiving a contractual rate of return or a date specified in the contractual arrangements, East West Bank will receive substantially all of the non-cash value attributable to the Groton Project, which includes accelerated depreciation and Section 48(a) investment tax credits; however, the Company will receive a majority of the cash distributions (based on the operating income of the Groton Project), which are paid quarterly. After East West Bank receives its contractual rate of return, the Company will receive approximately 95% of the cash and tax allocations. The Company (through a separate wholly owned entity) entered into a back leverage debt financing transaction during fiscal year 2023 and will use the cash distributions from the Groton Partnership to service the debt (refer to Note. 11. “Debt” for additional information). Since the Groton Project became operational during the year ended October 31, 2023, we have begun to allocate profits and losses to noncontrolling interests under the HLBV method. For the year ended October 31, 2023, the net loss attributable to noncontrolling interests totaled $2.5 million . ​ Yaphank Tax Equity Financing Transaction ​ The Company closed on a tax equity financing transaction in November 2021 with REI for the 7.4 MW fuel cell project (the “LIPA Yaphank Project”) located in Yaphank Long Island. REI’s tax equity commitment totaled $12.4 million. ​ This transaction was structured as a partnership flip. Under this partnership flip structure, a partnership, in this case YTBFC Holdco, LLC (the “Yaphank Partnership”), was organized to acquire from FuelCell Energy Finance II, LLC, a wholly-owned subsidiary of the Company, all outstanding equity interests in Yaphank Fuel Cell Park, LLC, which in turn owns the LIPA Yaphank Project and is the party to the power purchase agreement and all project agreements. . ​ The Company determined during the second quarter of fiscal year 2022 that there was an overpayment by REI of the Class A Member Capital Contribution of $0.5 million and as such the Company refunded this amount back to REI, reducing the REI tax equity commitment to $11.9 million. During the year ended October 31, 2022, the Company made priority return distributions to REI of $0.3 million, which was calculated at a 2.73% annual interest rate on invested tax equity capital. ​ Under a partnership flip structure, tax equity investors agree to receive a minimum target rate of return, typically on an after-tax basis. Prior to receiving a contractual rate of return or a date specified in the contractual arrangements, REI will receive substantially all of the non-cash value attributable to the LIPA Yaphank Project, which includes accelerated depreciation and Section 48(a) investment tax credits; however, the Company will receive a majority of the cash distributions (based on the operating income of the LIPA Yaphank Project), which are paid quarterly. After REI receives its contractual rate of return, the Company will receive approximately 95% of the cash and tax allocations. ​ Under this partnership flip structure, after the fifth anniversary following achievement of commercial operations, we have an option to acquire all of the equity interests that REI holds in the Yaphank Partnership starting after REI receives its contractual rate of return (the anticipated “flip” date) after the LIPA Yaphank Project is operational. If we exercise this option, we will be required to pay the greater of the following: (i) the fair market value of REI's equity interest at the time the option is exercised or (ii) an amount equal to 10.3% of REI’s capital contributions. This option payment is to be grossed up for federal taxes if it exceeds the tax basis of the Yaphank Partnership Class A Units. For the years ended October 31, 2023 and 2022, net income (loss) attributable to noncontrolling interest for the Yaphank Partnership totaled $2.0 million and ($4.5) million, respectively . ​ Toyota Investment Tax Credit Sale On October 31, 2023, REI purchased investment tax credits (“ITCs”) from Long Beach Trigen, LLC (“LB Seller”), a subsidiary of the Company. The Toyota project qualified for $8.4 million of ITCs. The total amount of the purchase was $7.1 million or $0.85 per $1.00 of purchased ITCs. The Company incurred transaction costs of $0.4 million for legal costs and advisory fees. Toyota Motor North America (“Toyota”) has a contractual right under the hydrogen production and power purchase agreement with the Company (“Toyota HPPA”) to receive the benefit of the ITCs and, as a result, the Company recorded the value of the net amount due to Toyota as an accrued liability totaling $6.3 million, which will be reduced over time based on the performance under the terms of the contract with Toyota (see Note 9. “Accrued Liabilities” for further information).

Investments - Short-Term

Investments - Short-Term	12 Months Ended
	Oct. 31, 2023
Investments - Short-Term
Investments - Short-Term	Note 4. Investments – Short-Term The Company’s U.S. Treasury Securities outstanding as of October 31, 2023 have maturity dates ranging from November 9, 2023 to January 23, 2024. We have classified our investments in U.S. Treasury Securities as held-to-maturity and recorded them at amortized cost. The following table summarizes the amortized cost basis and fair value (based on quoted market prices) as of October 31, 2023 (in thousands). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Gross unrealized ​ Gross unrealized ​ ​ cost ​ gains ​ losses Fair value U.S. Treasury Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2023 ​ $ 103,760 $ 1 $ — $ 103,761 ​ The weighted average yield to maturity is 5.45%.

Inventories

Inventories	12 Months Ended
	Oct. 31, 2023
Inventories
Inventories	​ Note 5. Inventories ​ Inventories (short and long-term) as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Raw materials ​ $ 36,200 ​ $ 30,624 Work-in-process (1) ​ ​ 55,585 ​ ​ 67,834 Inventories ​ ​ 91,785 ​ ​ 98,458 Inventories – current ​ ​ (84,456) ​ ​ (90,909) Inventories – long-term (2) ​ $ 7,329 ​ $ 7,549 (1) Work-in-process includes the standard components of inventory used to build the typical modules or module components that are intended to be used in future project asset construction or power platform orders or for use under the Company’s service agreements. (2) Long-term inventory includes modules that are contractually required to be segregated for use as replacement modules for a specific project asset . Raw materials consist mainly of various nickel powders and steels, various other components used in producing cell stacks and purchased components for BOP. Work-in-process inventory is comprised of material, labor, and overhead costs incurred to build fuel cell stacks and modules, which are subcomponents of a power platform.

Project Assets

Project Assets	12 Months Ended
	Oct. 31, 2023
Project Assets
Project Assets	Note 6. Project Assets Project assets as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ Estimated ​ 2023 2022 Useful Life Project Assets – Operating ​ $ 213,753 ​ $ 154,736 ​ 4-20 years Accumulated depreciation ​ ​ (46,263) ​ ​ (29,546) ​ ​ Project Assets – Operating, net ​ ​ 167,490 ​ ​ 125,190 ​ ​ Project Assets – Construction in progress ​ ​ 90,576 ​ ​ 107,696 ​ 7-20 years Project Assets, net ​ $ 258,066 ​ $ 232,886 ​ ​ ​ The estimated useful lives of these project assets are 20 years for BOP and site construction, and four Project assets as of October 31, 2023 and 2022 also include installations with carrying values of $90.6 million and $107.7 million, respectively, which are being developed and constructed by the Company in connection with projects for which we have entered into PPAs or projects for which we expect to secure PPAs or otherwise recover the asset value and which have not yet been placed in service. Fiscal Year 2023 Charges, Including Impairment Charges The 2.3 MW Toyota project (the “Toyota Project”) was included in “Construction in progress” as of October 31, 2023. It was determined in the fourth quarter of fiscal year 2021 that a potential source of renewable natural gas (“RNG”) at favorable pricing was no longer sufficiently probable and that market pricing for RNG had significantly increased, resulting in the determination that the project is expected to generate negative cash flows and that, therefore, the carrying value of the project asset was no longer recoverable. Refer to Note 19. “Commitments and Contingencies” for more information regarding fuel risk exposure. As this project was being constructed, only inventory components that could be redeployed for alternative use were capitalized. For the year ended October 31, 2023, non-recoverable costs incurred of $22.9 million have been expensed as generation cost of revenues. During fiscal year 2023, the Company recorded an impairment charge of $2.4 million related to a project for which a PPA was ultimately not awarded. Fiscal Year 2022 Charges, Including Impairment Charges In the fourth quarter of fiscal year 2022, the Company made the decision not to proceed with development of the 7.4 MW and 1.0 MW Hartford projects given the then current economic profile of these projects. As a result, the Company recorded a $0.8 million impairment charge. Charges for the year ended October 31, 2022 relating to the Toyota Project were $22.1 million, which represented the carrying value of the project asset less the carrying value of inventory components that could be redeployed for alternative use. Fiscal Year 2021 Impairment Charges In the fourth quarter of fiscal year 2021, the Company recorded project asset impairment charges for (i) the Triangle Street Project, (ii) the LIPA Brookhaven and Clare Rose Projects, and (iii) the Toyota Project, which are further described as follows: i. Impairment charge for the Triangle Street Project: In the fourth quarter of fiscal year 2021, based upon the carrying value of the components that could be removed and utilized to service similar project assets and due to the uncertainty as to whether the project asset would generate further cash flows, the Company recorded an impairment charge of $0.4 million. The remaining carrying value was $5.6 million as of October 31, 2021. ii. Impairment charge for the LIPA Brookhaven and Clare Rose Projects: As previously reported, in July 2017, the Company was awarded three projects on Long Island, New York totaling 39.8 MW by the Long Island Power Authority (“LIPA”). In December 2018, the Company executed a power purchase agreement for one of the three awards (a 7.4 MW project in Yaphank, Long Island). The other two awards, for which there are no executed power purchase agreements (and which are referred to herein as the LIPA Brookhaven and Clare Rose Projects), had been progressing through the required interconnect process while the Company worked to find a commercial resolution and enter into such agreements with LIPA. Given the passage of time without a resolution, the Company made a decision to no longer pursue the interconnection process and will no longer pursue development of the LIPA Brookhaven and Clare Rose Projects. As a result of this decision, in the fourth quarter of fiscal year 2021, the Company recorded a charge of $1.8 million to impair the carrying value of the development costs for these two projects. iii. Impairment charge for the Toyota Project: A $2.8 million charge was recorded in the fourth quarter of fiscal year 2021, which represented the carrying value of the project asset less the carrying value of inventory components that could be redeployed for alternative use. Impairment charges are recorded as cost of generation revenues in the Consolidated Statements of Operations and Comprehensive Loss. Depreciation expense for project assets was $19.0 million, $14.2 million and $13.7 million for the years ended October 31, 2023, 2022 and 2021, respectively. Project construction costs incurred for long-term project assets are reported as investing activities in the Consolidated Statements of Cash Flows. The proceeds received from the sale and subsequent leaseback of project assets are classified as “Cash flows from financing activities” within the Consolidated Statements of Cash Flows and are classified as a finance obligation within “Current portion of long-term debt” and “Long-term debt and other liabilities” on the Consolidated Balance Sheets (refer to Note 11. “Debt” for more information).

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Oct. 31, 2023
Property, Plant and Equipment.
Property Plant and Equipment	Note 7. Property, Plant and Equipment Property, plant and equipment as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ Estimated ​ ​ 2023 ​ 2022 ​ Useful Life Land ​ $ 524 ​ $ 524 ​ — Building and improvements ​ 21,430 ​ 21,216 10‑26 years Machinery, equipment and software ​ 136,554 ​ 108,656 3‑8 years Furniture and fixtures ​ 5,211 ​ 4,354 10 years Construction in progress ​ 33,950 ​ 26,484 — ​ ​ 197,669 ​ 161,234 ​ ​ Accumulated depreciation ​ (108,001) ​ (103,097) Property, plant and equipment, net ​ $ 89,668 ​ $ 58,137 ​ The Company recorded an impairment charge of approximately $1.0 million during the year ended October 31, 2022 (related to the cessation of operations at a conditioning facility in Danbury, CT, which was replaced by a new conditioning facility located at our Torrington, CT manufacturing facility). There were no impairments of property, plant and equipment for the years ended October 31, 2023 and 2021. Depreciation expense for property, plant and equipment was $5.1 million, $5.8 million and $4.9 million for the years ended October 31, 2023, 2022 and 2021, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Oct. 31, 2023
Goodwill and Intangible Assets
Goodwill and Intangible Assets	Note 8. Goodwill and Intangible Assets As of October 31, 2023 and 2022, the Company had goodwill of $4.1 million and intangible assets of $16.1 million and $17.4 million, respectively, that were recorded in connection with the Company’s 2012 acquisition of Versa Inc. and the 2019 Bridgeport Fuel Cell Project acquisition. The Versa Inc. acquisition intangible asset represents indefinite-lived IPR&D for cumulative research and development efforts associated with the development of solid oxide fuel cell stationary power generation. The Company completed its annual impairment analysis of goodwill and IPR&D assets as of July 31, 2023. The Company performed a qualitative analysis for fiscal year 2023 and determined that there was no impairment of goodwill or the indefinite-lived intangible asset. Additionally, there were no impairments of goodwill or the indefinite-lived intangible asset during fiscal year 2022 and 2021. Amortization expense for the Bridgeport Fuel Cell Project-related intangible asset was $1.3 million for each of the years ended October 31, 2023, 2022 and 2021. The following tables summarize the Company’s intangible assets as of October 31, 2023 and 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2023 Gross Amount Accumulated Amortization Net Amount In-Process Research and Development ​ $ 9,592 ​ $ — ​ $ 9,592 Bridgeport PPA ​ ​ 12,320 ​ ​ (5,836) ​ ​ 6,484 Total ​ $ 21,912 ​ $ (5,836) ​ $ 16,076 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2022 Gross Amount Accumulated Amortization Net Amount In-Process Research and Development ​ $ 9,592 ​ $ — ​ $ 9,592 Bridgeport PPA ​ ​ 12,320 ​ ​ (4,539) ​ ​ 7,781 Total ​ $ 21,912 ​ $ (4,539) ​ $ 17,373 ​ Amortization expense is recorded on a straight-line basis and future amortization expense will be $1.3 million per year until the Bridgeport PPA is fully amortized.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Oct. 31, 2023
Accrued Liabilities
Accrued Liabilities	Note 9. Accrued Liabilities Accrued liabilities as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Accrued payroll and employee benefits (1) ​ $ 7,752 ​ $ 8,534 Consideration payable to a customer (2) ​ ​ 3,958 ​ ​ — Accrued service agreement and PPA costs (3) ​ ​ 10,742 ​ ​ 11,340 Accrued legal, taxes, professional and other ​ ​ 3,861 ​ ​ 7,541 Accrued liabilities ​ $ 26,313 ​ $ 27,415 (1) The balance in this account represents accrued payroll, payroll taxes and accrued bonus for both periods. The decrease in the account balance relates to a decrease in accrued bonus as of October 31, 2023. (2) The balance represents the net amount due to Toyota as an accrued liability which will be reduced over time based on the performance under the terms of the Toyota HPPA. (3) Accrued service agreement costs include loss accruals on service contracts of $9.5 million as of October 31, 2023, which increased from $7.3 million as of October 31, 2022. The increase is the result of changes in estimates regarding timing of future module exchanges and future module replacement costs. The accruals for performance guarantees on service agreements and PPAs decreased from $4.1 million as of October 31, 2022 to $1.2 million as of October 31, 2023 .

Leases

Leases	12 Months Ended
	Oct. 31, 2023
Leases
Leases	Note 10. Leases The Company enters into operating and finance lease agreements for the use of real estate, vehicles, information technology equipment, and certain other equipment. We determine if an arrangement contains a lease at inception, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The impacts of accounting for operating leases are included in Operating lease right-of-use assets, Operating lease liabilities, and Long-term operating lease liabilities in the Company’s Consolidated Balance Sheets. Finance leases are not considered significant to the Company’s Consolidated Balance Sheets or Consolidated Statements of Operations and Comprehensive Loss. Operating lease expense for each of the years ended October 31, 2023, 2022 and 2021 was $1.5 million. As of October 31, 2023, the weighted average remaining lease term (in years) was approximately 17 years and the weighted average discount rate was 7.0%. Lease payments made during the years ended October 31, 2023, 2022 and 2021 totaled $1.2 million, $1.4 million, and $1.2 million, respectively. As of October 31, 2023, undiscounted maturities of operating lease and finance lease liabilities are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases Due Year 1 ​ $ 1,052 ​ $ 16 Due Year 2 ​ ​ 1,276 ​ ​ — Due Year 3 ​ ​ 1,262 ​ ​ — Due Year 4 ​ ​ 1,292 ​ ​ — Due Year 5 ​ ​ 1,267 ​ ​ — Thereafter ​ ​ 12,718 ​ ​ — Total undiscounted lease payments ​ ​ 18,867 ​ ​ 16 Less imputed interest ​ ​ (9,276) ​ ​ (4) Total discounted lease payments ​ $ 9,591 ​ $ 12 ​

Debt

Debt	12 Months Ended
	Oct. 31, 2023
Debt
Debt	Note 11. Debt Debt as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Connecticut Green Bank Loan ​ $ — ​ $ 4,800 Connecticut Green Bank Loan (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 3,507 Liberty Bank Term Loan Agreement (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 5,382 Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 5,382 Connecticut Green Bank Loan (Subordinated Back Leverage Loan Facility) ​ ​ 8,000 ​ ​ — Liberty Bank Loan (Senior Back Leverage Loan Facility) ​ ​ 5,876 ​ ​ — Amalgamated Bank Loan (Senior Back Leverage Loan Facility) ​ ​ 5,873 ​ ​ — Finance obligation for sale-leaseback transactions ​ ​ 18,814 ​ ​ 56,625 State of Connecticut Loan ​ ​ 6,908 ​ ​ 7,774 Finance lease obligations ​ ​ 12 ​ ​ 57 OpCo Financing Facility ​ ​ 77,510 ​ ​ — Deferred finance costs ​ ​ (3,526) ​ ​ (1,152) Total debt and finance obligations ​ ​ 119,467 ​ ​ 82,375 Current portion of long-term debt and finance obligations ​ ​ (10,067) ​ ​ (13,198) Long-term debt and finance obligations ​ $ 109,400 ​ $ 69,177 ​ Aggregate annual principal payments under our loan agreements, finance obligation, and finance lease obligations for the years subsequent to October 31, 2023 are as follows (in thousands): ​ ​ ​ ​ ​ Year 1 $ 10,712 Year 2 ​ 12,534 Year 3 ​ 12,475 Year 4 ​ 8,487 Year 5 ​ 9,858 Thereafter (1) ​ 59,858 ​ ​ $ 113,924 (1) The annual principal payments included above only include sale-leaseback payments whereas the difference between debt outstanding as of October 31, 2023 and the annual principal payments represent accreted interest and amounts included in the finance obligation that exceed required principal payments. During fiscal year 2023, the Company entered into the OpCo Financing Facility (described below), the proceeds of which were used, in part, to pay off (i) approximately $1.8 million of the Company’s long-term indebtedness to Connecticut Green Bank (the “Connecticut Green Bank Loan”), and (ii) all of the outstanding senior and subordinated indebtedness of the Company and/or its subsidiaries to Liberty Bank, Fifth Third Bank and Connecticut Green Bank related to the Bridgeport Fuel Cell Project. In addition, during fiscal year 2023, the Company entered into new financing facilities for the Groton Project, a portion of the proceeds of which were used to repay, in full, all of the Company’s remaining indebtedness under the Connecticut Green Bank Loan. ​ OpCo Financing Facility ​ On May 19, 2023, FuelCell Energy Opco Finance 1, LLC (“OpCo Borrower”), a wholly owned subsidiary of FuelCell Energy Finance, LLC (“FCEF”), which, in turn, is a wholly owned subsidiary of FuelCell Energy, Inc. (“Parent”), entered into a Financing Agreement (as amended, the “Financing Agreement”) with, by and among Investec Bank plc in its capacities as a lender (“Investec Lender”), administrative agent (“Administrative Agent”), and collateral agent (“Collateral Agent”); Investec, Inc. as coordinating lead arranger and sole bookrunner; Bank of Montreal (Chicago Branch) in its capacity as a lender (“BMO Lender”) and as mandated lead arranger; and each of Liberty Bank, Amalgamated Bank and Connecticut Green Bank as lenders (collectively with Investec Lender and BMO Lender, the “Lenders”) for a term loan facility in an amount not to exceed $80.5 million (the “Term Loan Facility” and such term loan, the “Term Loan”) and a letter of credit facility in an amount not to exceed $6.5 million (the “LC Facility” and together with the Term Loan Facility, the “OpCo Financing Facility”). OpCo Borrower’s obligations under the Financing Agreement are secured by Parent’s interest in six operating fuel cell generation projects: (i) the Bridgeport Fuel Cell Project, located in Bridgeport, Connecticut; (ii) the Central CT State University Project, located in New Britain, Connecticut; (iii) the Pfizer Project, located in Groton, Connecticut; (iv) the LIPA Yaphank Project, located in Long Island, New York; (v) the Riverside Regional Water Quality Control Plant Project, located in Riverside, California; and (vi) the Santa Rita Jail Project, located in Alameda County, California (each, a “Project” and collectively, the “Projects”). Immediately prior to the closing on the OpCo Financing Facility, which closing occurred on May 19, 2023, Parent caused to be transferred to OpCo Borrower all of the outstanding equity interests in: (i) Bridgeport Fuel Cell, LLC (the “Bridgeport Project Company”), the entity that owns the Bridgeport Fuel Cell Project; (ii) New Britain Renewable Energy, LLC (the “CCSU Project Company”), the entity that owns the Central CT State University Project; (iii) Groton Fuel Cell 1, LLC (the “Pfizer Project Company”), the entity that owns the Pfizer Project; (iv) Riverside Fuel Cell, LLC (the “Riverside Project Company”), the entity that owns the Riverside Regional Water Quality Control Plant Project; (v) SRJFC, LLC (the “Santa Rita Project Company”), the entity that owns the Santa Rita Jail Project; and (vi) Fuel Cell YT Holdco, LLC (the “Class B Member”), the entity that owns Parent’s Class B membership interest in YTBFC Holdco, LLC (the “Yaphank Tax Equity Partnership”), the tax equity partnership with Renewable Energy Investors, LLC (the “Class A Member”), as tax equity investor, which Yaphank Tax Equity Partnership, in turn, owns Yaphank Fuel Cell Park, LLC (the “Yaphank Project Company”), the entity that owns the LIPA Yaphank Project. ​ At the time of closing on the OpCo Financing Facility: (i) the Bridgeport Fuel Cell Project was encumbered by senior and subordinated indebtedness to Liberty Bank, Fifth Third Bank and Connecticut Green Bank in the aggregate amount of approximately $11.4 million; and (ii) the Pfizer Project, the Riverside Regional Water Quality Control Plant Project and the Santa Rita Jail Project were subject to sale and leaseback transactions and agreements with PNC Energy Capital, LLC (“PNC”) in which the lease buyout amounts, including sales taxes, were approximately $15.7 million, $3.7 million and $2.8 million, respectively. In connection with closing on the OpCo Financing Facility, all of the foregoing indebtedness and lease buyout amounts were repaid and extinguished with proceeds of the Term Loan and funds of approximately $7.3 million that were released from restricted and unrestricted reserve accounts held at PNC at the time of closing, resulting in the applicable project companies re-acquiring ownership of the three leased projects from PNC, the termination of the agreements with PNC related to the sale-leaseback transactions, and the termination of the senior and subordinated credit agreements with, the related promissory notes issued to, and the related pledge and security agreements with, Liberty Bank, Fifth Third Bank and Connecticut Green Bank related to the Bridgeport Fuel Cell Project. Further, in connection with the closing on the OpCo Financing Facility and the termination of the senior and subordinated credit agreements with Liberty Bank, Fifth Third Bank and Connecticut Green Bank related to the Bridgeport Fuel Cell Project, Fifth Third Bank and the Bridgeport Project Company agreed that the obligations arising out of the swap transactions contemplated by their related interest rate swap agreement were terminated and waived and the swap agreement was effectively terminated. In addition, in connection with closing on the OpCo Financing Facility, proceeds of the Term Loan were used to repay a portion of Parent’s long-term indebtedness to Connecticut Green Bank in the amount of approximately $1.8 million. At the closing, $80.5 million, the entire amount of the Term Loan portion of the OpCo Financing Facility, was drawn down. After payment of fees and transaction costs (including fees to the Lenders and legal costs) of approximately $2.9 million in the aggregate, the remaining proceeds of approximately $77.6 million were used as follows: (i) approximately $15.0 million was used (in addition to the approximately $7.3 million released from restricted and unrestricted reserve accounts held at PNC) to pay the lease buyout amounts and sales taxes referred to above and to re-acquire the three projects owned by PNC as referred to above; (ii) approximately $11.4 million was used to extinguish the indebtedness to Liberty Bank, Fifth Third Bank, and Connecticut Green Bank relating to the Bridgeport Fuel Cell Project; (iii) approximately $1.8 million was used to repay a portion of Parent’s long-term indebtedness to Connecticut Green Bank; (iv) $14.5 million was used to fund a capital expenditure reserve account required to be maintained pursuant to the terms and conditions of the Financing Agreement (which is classified as restricted cash on the Company’s Consolidated Balance Sheets); and (v) approximately $34.9 million was distributed to Parent for use as Parent determines in its sole discretion. In addition, in connection with the extinguishment of the Company’s indebtedness to Liberty Bank and Fifth Third Bank referred to above, approximately $11.2 million of restricted cash was released to the Company from Liberty Bank and Fifth Third Bank. Taking into consideration the release of such funds, the total net proceeds to the Company from these transactions were approximately $46.1 million. The Term Loan portion of the OpCo Financing Facility will accrue interest on the unpaid principal amount calculated from the date of such Term Loan until the maturity date thereof at a rate per annum during each Interest Period (as defined in the Financing Agreement) for such Term Loan equal to (A) with respect to SOFR Rate Loans, (i) the Adjusted Daily Compounded SOFR for such Interest Period with respect to SOFR Rate Loans plus plus Quarterly principal amortization obligations are also required to be made (based on 17-year ​ Pursuant to the terms and conditions of the Financing Agreement, OpCo Borrower is required to maintain a capital expenditures reserve to pay for expected module replacements. The total reserve balance is required to reach $29.0 million, $14.5 million of which was funded out of the closing advance of the Term Loan and the remainder of which is to be funded pursuant to an agreed upon funding schedule through cash flows generated by the Projects set forth in the Financing Agreement for the period of June 30, 2023 through December 31, 2029. Pursuant to the terms and conditions of the Financing Agreement, OpCo Borrower is required to maintain a debt service reserve of not less than six months of the scheduled principal and interest payments. The letter of credit component of the OpCo Financing Facility is for the purpose of obtaining letters of credit to satisfy such obligation; at the closing, an Irrevocable Letter of Credit was issued by Investec Bank plc as the issuing bank in favor of the Collateral Agent for the benefit of the Lenders in the amount of $6.5 million to satisfy the debt service reserve funding obligation. ​ Pursuant to the Financing Agreement, within 30 days of the financial close of the Financing Agreement, OpCo Borrower was required to enter into one or more hedge transactions, with a Lender or an affiliate thereof pursuant to one or more interest rate agreements, to hedge OpCo Borrower’s interest rate exposure relating to the Term Loan from floating to fixed. Such hedge transactions are required to be in effect at all times during the entire amortization period and have an aggregate notional amount subject to the hedge transactions at any time equal to at least 75% and no more than 105% of the aggregate principal balance of the Term Loan outstanding (taking into account scheduled amortization of the Term Loan). Upon closing, on May 19, 2023, OpCo Borrower entered into an ISDA 2002 Master Agreement (the “Investec Master Agreement”) and an ISDA Schedule to the 2002 Master Agreement (the “Investec Schedule”) with Investec Bank plc as a hedge provider, and an ISDA 2002 Master Agreement (the “BMO Master Agreement”) and an ISDA Schedule to the 2002 Master Agreement (the “BMO Schedule”) with Bank of Montreal (Chicago Branch) as a hedge provider. On May 22, 2023, OpCo Borrower executed the related trade confirmations for these interest rate swap agreements with these hedge providers to protect against adverse price movements in the floating SOFR rate associated with 100% of the aggregate principal balance of the Term Loan outstanding. Pursuant to the terms of such agreements, OpCo Borrower will pay a fixed rate of interest of 3.716%. The net interest rate across the Financing Agreement and the swap transaction is 6.366% in the first four years and 6.866% thereafter. The obligations of OpCo Borrower to the hedge providers under the interest rate swap agreements are treated as obligations under the Financing Agreement and, accordingly, are secured, on a pari passu basis, by the same collateral securing the obligations of OpCo Borrower under the Financing Agreement, which collateral is described below. The Company has not elected hedge accounting treatment and, as a result, the derivative will be remeasured to fair value quarterly, with the resulting gains/losses recorded to other income/expense. The fair value adjustments for the year ended October 31, 2023 resulted in a gain of $3.3 million. ​ The Financing Agreement contains certain reporting requirements and other affirmative and negative covenants which are customary for transactions of this type. Included in the covenants are covenants that: (i) the Yaphank Project Company obtain ongoing three year extensions of its current gas agreement; (ii) any annual operating expense budget that exceeds 115% of the Base Case Model (as defined in the Financing Agreement) for that year be approved by the Required Lenders (i.e., Lenders constituting more than 50% of the amounts loaned); (iii) OpCo Borrower maintain a debt service coverage ratio of not less than 1.20:1.00 (based on the trailing 12 months and tested every six months); and (iv) the Class B Member is required to exercise its option to purchase the Class A Member’s interest in the Yaphank Tax Equity Partnership during the six month period following the “Flip Point” as set forth in the limited liability company agreement for the Yaphank Tax Equity Partnership. The Financing Agreement also contains customary representations and warranties and customary events of default that cause, or entitle the Lenders to cause, the outstanding loans under the Financing Agreement to become immediately due and payable. The Term Loan may be prepaid at any time at the option of OpCo Borrower without premium or penalty other than any “liquidation costs” if such prepayment occurs other than at the end of an Interest Period. In addition, there are certain mandatory repayments required under the Financing Agreement, including in connection with any sale or disposition of all of the Projects or of any of the LIPA Yaphank Project, the Bridgeport Fuel Cell Project or the Pfizer Project. If the Company disposes of any of the Riverside Regional Water Quality Control Plant Project, the Santa Rita Jail Project or the Central CT State University Project, OpCo Borrower is required to prepay an amount of the Term Loan based on the then stipulated value of the disposed Project. ​ Simultaneously with OpCo Borrower entering into the Financing Agreement, FCEF (as pledgor), OpCo Borrower and each of the Bridgeport Project Company, the Pfizer Project Company, the Riverside Project Company, the Santa Rita Project Company, the CCSU Project Company and the Class B Member, each as a subsidiary grantor party and guarantor, entered into an Omnibus Guarantee, Pledge and Security Agreement (the “Security Agreement”) with Investec Bank plc as Collateral Agent, pursuant to which, as collateral for the Term Loan Facility, the LC Facility and the hedge agreements (i) FCEF granted to Collateral Agent a security interest in all of FCEF’s equity interest in OpCo Borrower; (ii) OpCo Borrower granted to Collateral Agent a security interest in all of OpCo Borrower’s assets consisting of its equity interests in the Bridgeport Project Company, the Pfizer Project Company, the Riverside Project Company, the Santa Rita Project Company, the CCSU Project Company and the Class B Member; (iii) each of the Bridgeport Project Company, the Pfizer Project Company, the Riverside Project Company, the Santa Rita Project Company and the CCSU Project Company granted to Collateral Agent a security interest in all of each such entity’s assets consisting principally of the respective generation facilities and project agreements; and (iv) the Class B Member granted to Collateral Agent a security interest in all of such Class B Member’s assets, consisting principally of its equity interest in the Yaphank Tax Equity Partnership. Pursuant to the Security Agreement, each of the subsidiary grantor parties jointly and severally guaranteed payment of all of the obligations secured by the Security Agreement. Simultaneously with the execution of the Financing Agreement, OpCo Borrower, Investec Bank plc as Collateral Agent and Administrative Agent and Liberty Bank as Depositary Agent entered into a Depositary Agreement (the “Depositary Agreement”) pursuant to which OpCo Borrower established certain accounts at Liberty Bank, all of which were pledged to Collateral Agent as security for the Term Loan Facility, the LC Facility and the hedge agreements, including a Revenue Account; a Debt Service Reserve Account; a Redemption Account (for prepayments); a Capital Expenditure Reserve Account; and a Distribution Reserve Account (in each case as defined in the Depositary Agreement). Pursuant to the terms of the Financing Agreement and the Depositary Agreement, OpCo Borrower may make quarterly distributions to FCEF and Parent provided that: (i) no Event of Default or Default (in each case as defined in the Financing Agreement) exists under the OpCo Financing Facility; (ii) all reserve accounts have been funded; (iii) no letter of credit loans or unpaid drawings are outstanding with regard to any drawn down letter of credit under the LC Facility; (iv) OpCo Borrower has maintained a greater than 1.20:1.00 debt service coverage ratio for the immediate 12 month period; and (v) no Cash Diversion Event (i.e., certain events that would adversely impact distributions to the Class B Member in connection with the LIPA Yaphank Project, as further defined in the Financing Agreement) has occurred. Beginning with the quarter ending June 2025 and continuing until the quarter ending March 2026, prior to making contributions to the Debt Service Reserve Account or the Capital Expenditure Reserve Account or having funds available for distribution, out of operating cash flow, OpCo Borrower is required to make a quarterly payment to the Administrative Agent (on behalf of the Lenders) in the amount of $675,000 per quarter to be applied to outstanding principal. ​ Back Leverage Financing On August 18, 2023, FuelCell Energy Finance Holdco, LLC (“Holdco Borrower”), a wholly owned subsidiary of FCEF, which, in turn, is a wholly owned subsidiary of Parent, entered into: (i) a Credit Agreement (the “Senior Back Leverage Credit Agreement”) with, by and among Liberty Bank, in its capacities as a lender (“Liberty Lender”), administrative agent (the “Senior Administrative Agent”), and lead arranger, and Amalgamated Bank, in its capacity as a lender (“Amalgamated Lender” and, collectively with Liberty Lender, the “Senior Back Leverage Lenders”), for a term loan facility in an amount not to exceed an aggregate of $12.0 million to be provided 50% by Liberty Lender and 50% by Amalgamated Lender (such facility, the “Senior Back Leverage Loan Facility,” each such term loan, a “Senior Back Leverage Loan” and such term loans together, the “Senior Back Leverage Loans”); and (ii) a Credit Agreement (the “Subordinated Back Leverage Credit Agreement”) with Connecticut Green Bank, as administrative agent (the “Subordinated Administrative Agent”) and lender (“Subordinated Back Leverage Lender”), for a term loan facility in an amount not to exceed $8.0 million (such facility, the “Subordinated Back Leverage Loan Facility” and such term loan, the “Subordinated Back Leverage Loan”). The Senior Back Leverage Lenders and the Subordinated Back Leverage Lender are referred to collectively as the “Back Leverage Lenders.” Holdco Borrower’s obligations under the Senior Back Leverage Credit Agreement and the Subordinated Back Leverage Credit Agreement are secured by a lien on all of Holdco Borrower’s assets, consisting principally of its Class B Member Interests (the “Class B Interests”) in Groton Station Fuel Cell Holdco, LLC (the “Groton Tax Equity Holdco”). Class A Membership Interests (the “Class A Interests”) in the Groton Tax Equity Holdco are held by East West Bank. Holdco Borrower is also the Managing Member of the Groton Tax Equity Holdco. The Groton Tax Equity Holdco’s primary asset is ownership of all of the outstanding equity interests in Groton Station Fuel Cell, LLC (the “Groton Project Company”). The Groton Project Company, in turn, is the owner of the fuel cell power plant at the U.S. Navy Submarine Base New London located in Groton, Connecticut (the “Groton Project”). As additional context concerning the relationship among the parties with respect to the Senior Back Leverage Loan Facility and the Subordinated Back Leverage Loan Facility more fully described below, on December 16, 2022, the Groton Project Company and Parent entered into an Amended and Restated Power Purchase Agreement (the “Amended and Restated PPA”) with Connecticut Municipal Electric Energy Cooperative (“CMEEC”), pursuant to which the Groton Project Company agreed to sell to CMEEC, and CMEEC agreed to purchase from the Groton Project Company, all of the electricity output produced by the Groton Project pursuant to the terms and conditions of the Amended and Restated PPA. ​ At the closing (the “Closing”) of each of the Senior Back Leverage Loan Facility and the Subordinated Back Leverage Loan Facility, which occurred simultaneously on August 18, 2023 (the “Closing Date”), the entire amount of each of the Senior Back Leverage Loan Facility and the Subordinated Back Leverage Loan Facility was drawn down in the aggregate amount of $20.0 million. After payment of fees and transaction costs (including fees to the Back Leverage Lenders and legal costs) of approximately $0.4 million in the aggregate, the remaining proceeds of approximately $19.6 million were used as follows: (i) approximately $1.7 million was used to fund debt service reserve accounts (“DSCR Reserve Accounts”) for the Senior Back Leverage Lenders in equal amounts of approximately $0.83 million for Liberty Lender and approximately $0.83 million for Amalgamated Lender; (ii) approximately $6.5 million was used to fund operations and maintenance and module replacement reserve accounts for the Senior Back Leverage Lenders in equal amounts of approximately $3.25 million for Liberty Lender and approximately $3.25 million for Amalgamated Lender; (iii) approximately $0.3 million was used to fund a DSCR Reserve Account for the Subordinated Back Leverage Lender; and (iv) the remaining amount of approximately $11.1 million was released to Parent from the Back Leverage Lenders. As discussed in additional detail below, simultaneous with the Closing, a portion of the proceeds were used to: (a) make Output Shortfall Payments (which are cash payments required to be made by the Groton Project Company in the event that the Groton Project produces electricity in any year less than the minimum required amount for such year) totaling approximately $1.3 million, which were deposited into a payment reserve account, and (b) pay approximately $3.0 million to Connecticut Green Bank, which represented payment, in full, of all outstanding obligations under Parent’s loan agreement with Connecticut Green Bank. After taking into account such Output Shortfall Payments and such payment to Connecticut Green Bank, approximately $6.8 million will be classified as unrestricted cash on the Company’s Consolidated Balance Sheet. The portion of the Senior Back Leverage Loan provided by Liberty Lender will accrue interest on the unpaid principal amount calculated from the date of such Senior Back Leverage Loan until the maturity date at a rate per annum equal to 6.75%. The portion of the Senior Back Leverage Loan provided by Amalgamated Lender will accrue interest on the unpaid principal amount calculated from the date of such Senior Back Leverage Loan until the maturity date thereof at 6.07% during all times at which a “Carbon Offset Event” is not continuing and 7.32% at all times at which a “Carbon Offset Event” has occurred and is continuing. A “Carbon Offset Event” is deemed to occur if Holdco Borrower, Parent or any direct or indirect subsidiary thereof does not purchase carbon offsets from an Acceptable Carbon Offset Provider (as defined below) each fiscal year in an amount equal to the lesser of (i) the Annual Carbon Offset Requirement for such fiscal year, which is derived based on a formula equal to the outstanding balance of the Senior Back Leverage Loan provided by Amalgamated Lender multiplied by the Groton Project’s annual carbon emissions for such year and divided by the total project costs of the Groton Project, and (ii) the Annual Carbon Offset Cap for such fiscal year, which is $12.66 multiplied by the Annual Carbon Offset Requirement and divided by the Carbon Offset Price for such fiscal year. The “Carbon Offset Price” means the price, per metric ton of carbon dioxide, of the carbon offsets available for purchase from an Acceptable Carbon Offset Provider. Quarterly principal amortization and interest payments are required to be made by Holdco Borrower on the Senior Back Leverage Loans based on a ten-year amortization period. The Senior Back Leverage Loans have a seven-year term, maturing on August 18, 2030, at which time all outstanding principal is due. The Subordinated Back Leverage Loan will accrue interest at a rate per annum equal to 8% for the period of time prior to the “Step Down Date” and, after the “Step Down Date,” at the lesser of 8% or the interest rate on a 10 year U.S. Treasury Note plus 275 basis points (subject to a minimum floor of 5% per annum). The “Step Down Date” is the date on which both of the following events have occurred: Holdco Borrower has purchased East West Bank’s Class A Interests in the Groton Tax Equity Holdco and the Senior Back Leverage Loans have been repaid in full. Interest is payable each quarter based on an agreed upon schedule. Pursuant to the Subordinated Back Leverage Loan Facility, during the “Interest Only Period” (as defined below), Holdco Borrower is required to make quarterly payments of principal in amounts equal to 50% of excess cash flow available to Holdco Borrower. For purposes of the foregoing, excess cash flow is all excess cash flow of Holdco Borrower after the payment of required principal and interest on the Senior Back Leverage Loans, required deposits in the various reserve accounts, the payment of interest on the Subordinated Back Leverage Loan and payment of Holdco Borrower’s operating expenses. Following the end of the “Interest Only Period,” principal and interest payments are required to be made quarterly in quarterly level payments (“mortgage style”) of principal and interest until the maturity date, which is the first to occur of 20 years following the Groton Project’s commercial operations date and termination of the Amended and Restated PPA. The maturity date of the Subordinated Back Leverage Loan Facility is currently contemplated to be September 30, 2038. The “Interest Only Period” is the period beginning on the Closing Date and ending the first to occur of (i) eighty-four months after the Closing Date; or (ii) the date the Senior Back Leverage Loan Facility has been fully repaid. Each of the Senior Back Leverage Credit Agreement and the Subordinated Back Leverage Credit Agreement contains certain reporting requirements and other affirmative and negative covenants which are customary for transactions of this type. Included in the covenants are covenants that: (i) Holdco Borrower maintain a “Senior” debt service coverage ratio (which is computed taking into account debt service obligations on the Senior Back Leverage Loans) of not less than 1.20:1.00 (based on the trailing 12 months and tested every quarter) and a “Total” debt service coverage ratio (which is computed taking into account debt service obligations on both the Senior Back Leverage Loans and the Subordinated Back Leverage Loan) of not less than 1.10:1.00 (based on the trailing 12 months and tested on a quarterly basis); (ii) Holdco Borrower may make distributions or dividends only if the foregoing debt to equity coverage ratios have been satisfied and Holdco Borrower is not in default under any provisions of either the Senior Back Leverage Credit Agreement or the Subordinated Back Leverage Credit Agreement, including having made all required deposits into reserve accounts; (iii) Holdco Borrower is required to exercise its right under the Groton Tax Equity Holdco limited liability company agreement to acquire the Class A Interests from East West Bank during the ninety day period beginning on the “Flip Point” (which, pursuant to the Groton Tax Equity Holdco limited liability company agreement, is the date on which the holder of Class A Interests has realized a certain return on investment and, accordingly, Holdco Borrower, as holder of the Class B Interests, has the right to purchase the Class A Interests); and (iv) the consent of the Senior Administrative Agent is required prior to Holdco Borrower’s taking certain material actions under the Groton Tax Equity Holdco limited liability company agreement. Each of the Senior Back Leverage Credit Agreement and the Subordinated Back Leverage Credit Agreement also contains customary representations and warranties and customary events of default that cause, or entitle the Back Leverage Lenders to cause, the outstanding loans to become immediately due and payable. In addition to customary events of default for transactions of this kind, the events of default include if a Change of Control occurs (meaning Parent no longer directly or indirectly owns Holdco Borrower), a cross default (meaning that a default under the Senior Back Leverage Loan Facility shall be deemed a default under the Subordinated Back Leverage Loan Facility and vice versa) or if CMEEC should become insolvent, is in bankruptcy or commits a specified number of payment defaults with regard to its payment obligations to the Groton Project Company. The Senior Back Leverage Loans may be prepaid at any time at the option of Holdco Borrower provided that (i) each prepayment on or prior to the second anniversary of the Closing Date shall require a prepayment fee of 3% of the principal amount being prepaid; (ii) each prepayment after the second anniversary of the Closing Date but on or prior to the fourth anniversary of the Closing Date shall require a prepayment fee of 2% of the principal amount being prepaid; and (iii) each prepayment after the fourth anniversary of the Closing Date but on or prior to the seventh anniversary of the Closing Date shall require a prepayment fee of 1% of the principal amount being prepaid. The Subordinated Back Leverage Loan may be prepaid at any time without premium or penalty. Orion Energy Partners Investment Agent, LLC Credit Agreement On October 31, 2019, the Company and certain of its affiliates as guarantors entered into a Credit Agreement (as amended, the “Orion Credit Agreement”) with Orion Energy Partners Investment Agent, LLC, as Administrative Agent and Collateral Agent (the “Orion Agent ”), and certain lenders affiliated with the Orion Agent for a $200.0 million senior secured credit facility (the “Orion Facility”). On November 30, 2020, the Company, its subsidiary guarantors, and the Orion Agent entered into a payoff letter with respect to the Orion Credit Agreement (the “Orion Payoff Letter”). Pursuant to the Orion Payoff Letter, on December 7, 2020, the Company paid a total of $87.3 million to the Orion Agent, representing the outstanding principal, accrued but unpaid interest, prepayment premium, fees, costs and other expenses due and owing under the Orion Facility and the Orion Credit Agreement and related loan documents, in full repayment of the Company’s outstanding indebtedness under the Orion Facility and the Orion Credit Agreement and related loan documents. In acco

Stockholders' Equity and Warran

Stockholders' Equity and Warrant Liabilities	12 Months Ended
	Oct. 31, 2023
Stockholders' Equity and Warrant Liabilities
Stockholders' Equity and Warrant Liabilities	Note 12. Stockholders’ Equity and Warrant Liabilities Increase in Authorized Shares The Company obtained stockholder approval on October 10, 2023 at a Special Meeting of Stockholders to increase the number of shares of common stock the Company is authorized to issue under the Company’s Certificate of Incorporation, as amended. The Company’s stockholders approved a 500.0 million increase in the number of authorized shares of common stock. Accordingly, on October 11, 2023, the Company filed a Certificate of Amendment of the Certificate of Incorporation of the Company with the Delaware Secretary of State increasing the total number of authorized shares of common stock from 500.0 million to 1.0 billion shares. The Company previously obtained stockholder approval on April 8, 2021 at the 2021 Annual Meeting of Stockholders to increase the number of shares of common stock the Company is authorized to issue under the Company’s Certificate of Incorporation, as amended. At that time, the Company’s stockholders approved a 162.5 million increase in the number of authorized shares of common stock. Accordingly, on April 8, 2021, the Company filed a Certificate of Amendment of the Certificate of Incorporation of the Company with the Delaware Secretary of State increasing the total number of authorized shares of common stock from 337.5 million shares to 500.0 million shares. Open Market Sale Agreements and At Market Issuance Sales Agreement 2022 Open Market Sale Agreement On July 12, 2022, the Company entered into an Open Market Sale Agreement with Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canaccord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC (the “Open Market Sale Agreement”) with respect to an at the market offering program under which the Company may, from time to time, offer and sell up to 95.0 million shares of the Company’s common stock. Pursuant to the Open Market Sale Agreement, the Company is required to pay each agent a commission equal to 2.0% of the gross proceeds from each sale of shares made by such agent under the Open Market Sale Agreement. From the date of the Open Market Sale Agreement through October 31, 2023, the Company sold approximately 62.8 million shares under the Open Market Sale Agreement at an average sale price of $2.66 per share, resulting in gross proceeds of approximately $166.8 million before deducting sales commissions and fees, and net proceeds to the Company of approximately $162.7 million after deducting commissions and fees totaling approximately $4.1 million. During the year ended October 31, 2023, approximately 44.3 million shares were sold under the Open Market Sale Agreement at an average sale price of $2.25 per share, resulting in gross proceeds of approximately $99.7 million before deducting sales commissions and fees, and net proceeds to the Company of approximately $97.4 million after deducting sales commissions and fees totaling approximately $2.3 million. As of October 31, 2023, approximately 32.2 million shares were available for issuance under the Open Market Sale Agreement. ​ 2021 Open Market Sale Agreement On June 11, 2021, the Company entered into an Open Market Sale Agreement with Jefferies LLC and Barclays Capital Inc. (the “2021 Sales Agreement”) with respect to an at the market offering program under which the Company could, from time to time, offer and sell shares of the Company’s common stock having an aggregate offering price of up to $500 million. Pursuant to the 2021 Sales Agreement, the Company paid the agent making each sale a commission equal to 2.0% of the aggregate gross proceeds it received from such sale by such agent of shares under the 2021 Sales Agreement. From the date of the 2021 Sales Agreement through April 30, 2022, approximately 64.0 million shares of the Company’s common stock were sold under the 2021 Sales Agreement at an average sales price of $7.79 per share, resulting in aggregate gross proceeds of approximately $498.1 million, before deducting sales commissions. Commissions of approximately $10.0 million in the aggregate were paid to Jefferies LLC and Barclays Capital Inc. in connection with these sales, resulting in aggregate net proceeds to the Company of approximately $488.1 million. Of these sales, approximately 19.9 million shares were sold under the 2021 Sales Agreement during the fiscal year ended October 31, 2022 at an average sales price of $6.07 per share, resulting in gross proceeds during the fiscal year ended October 31, 2022 of $120.8 million, before deducting expenses and sales commissions, and net proceeds to the Company of approximately $118.3 million after deducting commissions and offering expenses totaling approximately $2.4 million . ​ No sales of common stock were made under the 2021 Sales Agreement after April 30, 2022, and no additional sales of common stock can or will be made under the 2021 Sales Agreement, as the Company, Jefferies LLC and Barclays Capital Inc. mutually agreed to terminate the 2021 Sales Agreement as of July 12, 2022. Public Offerings and Warrants December 2020 Common Stock Offering In December of 2020, the Company and Orion Energy Credit Opportunities Fund II, L.P., Orion Energy Credit Opportunities Fund II GPFA, L.P., Orion Energy Credit Opportunities Fund II PV, L.P., and Orion Energy Credit Opportunities FuelCell Co-Invest, L.P. (the lenders under the Orion Credit Agreement) (the “Selling Stockholders”) completed a public offering of the Company’s common stock. In connection with this public offering, the Company and the Selling Stockholders entered into an underwriting agreement pursuant to which (i) the Company agreed to issue and sell to the underwriters 19,822,219 shares of the Company’s common stock, plus up to 5,177,781 shares of common stock pursuant to an option to purchase additional shares, and (ii) the Selling Stockholders agreed to sell to the underwriters 14,696,320 shares of common stock, in each case at a price to the public of $6.50 per share. The underwriters exercised their option to purchase additional shares, resulting in the issuance and sale by the Company at the closing of the offering of a total of 25,000,000 shares of common stock. The offering closed on December 4, 2020. Gross proceeds from the sale of common stock by the Company in the offering were $162.5 million. The Company did not receive any proceeds from the sale of common stock in the offering by the Selling Stockholders. The Company and the Selling Stockholders paid underwriting discounts and commissions of $0.2275 per share, and net proceeds to the Company were approximately $156.4 million after deducting such underwriting discounts and commissions and other offering expenses. May 2017 Public Offering and Related Warrants On May 3, 2017, the Company completed an underwritten public offering that included the offering and sale of Series C warrants to purchase 1,000,000 shares of its common stock. The Series C warrants had an exercise price of $19.20 per share and a term of five years. During the year ended October 31, 2021, Series C warrants were exercised to purchase a total of 14,026 shares of the Company’s common stock, resulting in cash proceeds to the Company of $0.3 million during fiscal year 2021. No Series C warrants were exercised during the fiscal year ended October 31, 2022, and the Series C warrants expired in May 2022. Orion Warrants In connection with the closing of, and the initial funding under, the Orion Credit Agreement, on October 31, 2019, the Company issued warrants to the lenders under the Orion Credit Agreement to purchase up to a total of 6,000,000 shares of the Company’s common stock, at an exercise price of $0.310 per share (the “Initial Funding Warrants”). In addition, on the date of the second funding under the Orion Credit Agreement (November 22, 2019), the Company issued warrants to the lenders under the Orion Credit Agreement to purchase up to a total of 14,000,000 shares of the Company’s common stock, with an exercise price with respect to 8,000,000 of such shares of $0.242 per share and with an exercise price with respect to 6,000,000 of such shares of $0.620 per share (the “Second Funding Warrants”, and together with the Initial Funding Warrants, the “Orion Warrants”). On December 7, 2020, all of the then remaining Orion Warrants were exercised to purchase a total of 2,700,000 shares of the Company’s common stock for an aggregate exercise price of approximately $0.6 million (or $0.242 per share). The Orion Warrants that were converted on December 7, 2020 were remeasured to fair value immediately preceding the conversion which resulted in a $16.0 million charge for the year ended October 31, 2021. The estimated fair value of the converted Orion Warrants as of the December 7, 2020 date of conversion of $21.2 million was reclassified to Additional paid-in capital. ​

Redeemable Preferred Stock

Redeemable Preferred Stock	12 Months Ended
	Oct. 31, 2023
Redeemable Preferred Stock
Redeemable Preferred Stock	Note 13. Redeemable Preferred Stock The Company is authorized to issue up to 250,000 shares of preferred stock, par value $0.01 per share, in one or more series, of which 105,875 shares were designated as 5% Series B Cumulative Convertible Perpetual Preferred Stock (referred to herein as Series B Preferred Stock) in March 2005. Redeemable Series B Preferred Stock The Company has designated 105,875 shares of its authorized preferred stock as Series B Preferred Stock (liquidation preference $1,000.00 per share). As of October 31, 2023 and 2022, there were 64,020 shares of Series B Preferred Stock issued and outstanding, with a carrying value of $59.9 million. The following is a summary of certain terms of the Series B Preferred Stock. Ranking. ● senior to shares of the Company’s common stock; ● junior to the Company’s debt obligations; and ● effectively junior to the Company’s subsidiaries’ (i) existing and future liabilities and (ii) capital stock held by others. Dividends. The dividend rate is subject to upward adjustment as set forth in the Amended Certificate of Designation for the Series B Preferred Stock (the “Series B Certificate of Designation”) if the Company fails to pay, or to set apart funds to pay, any quarterly dividend on the Series B Preferred Stock. No dividends or other distributions may be paid or set apart for payment on the Company’s common stock (other than a dividend payable solely in shares of a like or junior ranking), nor may any stock junior to or on parity with the Series B Preferred Stock be redeemed, purchased or otherwise acquired for any consideration (or any money paid to or made available for a sinking fund for such stock) by the Company or on its behalf  (except by conversion into or exchange for shares of a like or junior ranking), unless all accumulated and unpaid dividends on the Series B Preferred Stock have been paid or funds or shares of common stock have been set aside for payment of such accumulated and unpaid dividends. The dividends on the Series B Preferred Stock will be paid in cash, unless a registered holder elects (pursuant to the procedures set forth in the Series B Certificate of Designation) to receive such dividends in shares of the Company’s common stock. Any such shares of common stock paid in lieu of cash dividends will be treated as restricted securities and will not be transferable by the recipient thereof except pursuant to an effective registration statement or pursuant to an exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). Liquidation. Conversion Rights The Company may, at its option, cause shares of Series B Preferred Stock to be automatically converted into that number of shares of its common stock that are issuable at the then-prevailing conversion rate. The Company may exercise its conversion right only if the closing price of its common stock exceeds 150% of the then-prevailing conversion price ($1,692.00 per share as of October 31, 2023) for 20 trading days during any consecutive 30 trading day period, as described in the Series B Certificate of Designation. If the holders of Series B Preferred Stock elect to convert their shares in connection with certain “fundamental changes” (as defined in the Series B Certificate of Designation and described below), the Company will in certain circumstances increase the conversion rate by a number of additional shares of common stock upon conversion or, in lieu thereof, the Company may in certain circumstances elect to adjust the conversion rate and related conversion obligation so that shares of Series B Preferred Stock are converted into shares of the acquiring or surviving company, in each case as described in the Series B Certificate of Designation. The adjustment of the conversion price is to prevent dilution of the interests of the holders of the Series B Preferred Stock from certain dilutive transactions with holders of the Company’s common stock. Redemption. ● any “person” or “group” is or becomes the beneficial owner, directly or indirectly, of 50% or more of the total voting power of all classes of the Company’s capital stock then outstanding and normally entitled to vote in the election of directors; ● during any period of two consecutive years, individuals who at the beginning of such period constituted the board of directors of the Company (together with any new directors whose election to the Company’s board of directors or whose nomination for election by the stockholders was approved by a vote of 66 2/3% of the Company’s directors then still in office who were either directors at the beginning of such period or whose election or nomination for election was previously so approved) cease for any reason to constitute a majority of the directors of the Company then in office; ● the termination of trading of the Company’s common stock on The Nasdaq Stock Market and the common stock is not approved for trading or quoted on any other U.S. securities exchange or established over-the-counter trading market in the U.S.; or ● the Company (i) consolidates with or merges with or into another person or another person merges with or into the Company or (ii) sells, assigns, transfers, leases, conveys or otherwise disposes of all or substantially all of the assets of the Company and certain of its subsidiaries, taken as a whole, to another person and, in the case of any such merger or consolidation described in clause (i), the securities that are outstanding immediately prior to such transaction (and which represent 100% of the aggregate voting power of the Company’s voting stock) are changed into or exchanged for cash, securities or property, unless pursuant to the transaction such securities are changed into or exchanged for securities of the surviving person that represent, immediately after such transaction, at least a majority of the aggregate voting power of the voting stock of the surviving person. Notwithstanding the foregoing, holders of shares of the Series B Preferred Stock will not have the right to require the Company to redeem their shares if: ● the last reported sale price of shares of the Company’s common stock for any five trading days within the 10 consecutive trading days ending immediately before the later of the fundamental change or its announcement equaled or exceeded 105% of the conversion price of the Series B Preferred Stock immediately before the fundamental change or announcement; ● at least 90% of the consideration (excluding cash payments for fractional shares and in respect of dissenters’ appraisal rights) in the transaction or transactions constituting the fundamental change consists of shares of capital stock traded on a U.S. national securities exchange or quoted on The Nasdaq Stock Market, or which will be so traded or quoted when issued or exchanged in connection with a fundamental change, and as a result of the transaction or transactions, shares of Series B Preferred Stock become convertible into such publicly traded securities; or ● in the case of a merger or consolidation constituting a fundamental change (as described in the fourth bullet above), the transaction is affected solely to change the Company’s jurisdiction of incorporation. Moreover, the Company will not be required to redeem any Series B Preferred Stock upon the occurrence of a fundamental change if a third party makes an offer to purchase the Series B Preferred Stock in the manner, at the price, at the times and otherwise in compliance with the requirements set forth above and such third party purchases all shares of Series B Preferred Stock validly tendered and not withdrawn. The Company may, at its option, elect to pay the redemption price in cash, in shares of the Company’s common stock valued at a discount of 5% from the market price of shares of the Company’s common stock, or in any combination thereof. Notwithstanding the foregoing, the Company may only pay such redemption price in shares of the Company’s common stock that are registered under the Securities Act and eligible for immediate sale in the public market by non-affiliates of the Company. Voting Rights. So long as any shares of Series B Preferred Stock remain outstanding, the Company will not, without the consent of the holders of at least two-thirds of the shares of Series B Preferred Stock outstanding at the time (voting separately as a class with all other series of preferred stock, if any, on parity with the Series B Preferred Stock upon which like voting rights have been conferred and are exercisable) issue or increase the authorized amount of any class or series of shares ranking senior to the outstanding shares of the Series B Preferred Stock as to dividends or upon liquidation. In addition, the Company will not, subject to certain conditions, amend, alter or repeal provisions of the Company’s certificate of incorporation, as amended, including the Series B Certificate of Designation, whether by merger, consolidation or otherwise, so as to adversely amend, alter or affect any power, preference or special right of the outstanding shares of Series B Preferred Stock or the holders thereof without the affirmative vote of not less than two-thirds of the issued and outstanding shares of Series B Preferred Stock. The amendment of the Company’s certificate of incorporation in October 2023 did not trigger this provision.

Segment Information

Segment Information	12 Months Ended
	Oct. 31, 2023
Segment Information
Segment Information	Note 14. Segment Information We are engaged in the development, design, production, construction, and servicing of high temperature fuel cells for clean electric power generation. Critical to the success of our business is, among other things, our research and development efforts, both through customer-sponsored projects and Company-sponsored projects. The research and development activities are viewed as another product line that contributes to the development, design, production and sale of fuel cell products, however, it is not considered a separate operating segment. The chief operating decision maker does not review and assess financial information at a discrete enough level to be able to assess performance of research and development activities as if they operated as a standalone business segment, therefore, the Company has identified one business segment: fuel cell power plant production and research. Revenues, by geographic location (based on the customer’s ordering location) for the years ended October 31, 2023, 2022 and 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 United States ​ $ 63,289 ​ $ 60,290 ​ $ 58,393 South Korea ​ 58,432 ​ 68,341 ​ 8,161 Europe ​ 1,673 ​ 1,853 ​ 3,031 Total ​ $ 123,394 ​ $ 130,484 ​ $ 69,585 ​ Long-lived assets located outside of the United States as of October 31, 2023 and 2022 are not significant individually or in the aggregate.

Benefit Plans

Benefit Plans	12 Months Ended
	Oct. 31, 2023
Benefit Plans
Benefit Plans	Note 15. Benefit Plans We have stockholder approved equity incentive plans, a stockholder approved Employee Stock Purchase Plan and an employee tax-deferred savings plan, which are described in more detail below. Third Amended and Restated 2018 Omnibus Incentive Plan At the Company’s 2023 Annual Meeting of Stockholders, which was called to order and adjourned on April 6, 2023 and April 27, 2023 and was reconvened and concluded on May 22, 2023 (the “Annual Meeting”), the Company’s stockholders approved the amendment and restatement of the FuelCell Energy, Inc. Second Amended and Restated 2018 Omnibus Incentive Plan (as so amended and restated, the “Third Amended and Restated Incentive Plan”), which had previously been approved by the Company’s Board of Directors (the “Board”), subject to stockholder approval. The purpose of the amendment and restatement of the Second Amended and Restated 2018 Omnibus Incentive Plan was to authorize the Company to issue up to 6,000,000 additional shares of the Company’s common stock pursuant to awards under the Third Amended and Restated Incentive Plan. Following the approval of the amendment and restatement (and therefore the Third Amended and Restated Incentive Plan) by the Company’s stockholders at the Annual Meeting, the Third Amended and Restated Incentive Plan provides the Company with the authority to issue a total of 18,333,333 shares of the Company’s common stock. The Third Amended and Restated Incentive Plan authorizes grants of stock options, stock appreciation rights (“SARs”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), shares, performance shares, performance units, incentive awards and dividend equivalent units to officers, other employees, directors, consultants and advisors. Up to 1,833,333 shares of the Company’s common stock may be issued pursuant to the exercise of incentive stock options. Stock options, RSAs, RSUs and SARs have restrictions as to transferability. Stock option exercise prices are fixed by the Board but shall not be less than the fair market value of our common stock on the date of the grant. SARs may be granted in conjunction with stock options. The Board or the administrator of the Third Amended and Restated Incentive Plan may terminate the Third Amended and Restated Incentive Plan at any time. No award may be granted under the Third Amended and Restated Plan after the tenth anniversary of the approval of the Third Amended and Restated Plan by stockholders at the Annual Meeting Of the 18,333,333 shares of the Company’s common stock authorized to be issued under the Third Amended and Restated Incentive Plan as of October 31, 2023, 9,069,450 remained available for grant as of October 31, 2023. Of the shares remaining available for grant, the Company had reserved, for potential future grant, up to 1,481,395 performance stock units if maximum performance is achieved. Amended and Restated 2018 Employee Stock Purchase Plan At the Annual Meeting, the Company’s stockholders approved the amendment and restatement of the FuelCell Energy, Inc. 2018 Employee Stock Purchase Plan (as so amended and restated, the “Amended and Restated ESPP”), which had previously been approved by the Board, subject to stockholder approval. The purpose of the amendment and restatement of the 2018 Employee Stock Purchase Plan was to authorize the Company to issue up to 500,000 additional shares of the Company’s common stock under the Amended and Restated ESPP. Following the approval of the amendment and restatement (and therefore the Amended and Restated ESPP) by the Company’s stockholders at the Annual Meeting, the Amended and Restated ESPP provides the Company with the authority to issue a total of 541,667 shares of the Company’s common stock. The Amended and Restated ESPP also increases the limit on the number of shares of the Company’s common stock that any individual participant may purchase during an offering period to 1,000 shares. The Amended and Restated ESPP, which is intended to satisfy the requirements of Section 423 of the Internal Revenue Code of 1986, as amended, allows the Company to provide eligible employees of the Company and of certain designated subsidiaries with the opportunity to voluntarily participate in the Amended and Restated ESPP, enabling such participants to purchase shares of the Company’s common stock at a discount to market price at the time of such purchase. The Board may, in its sole discretion, terminate the Amended and Restated ESPP at any time. If the Board does not earlier terminate the Amended and Restated ESPP, the Amended and Restated ESPP will terminate on the date on which all shares of common stock available for issuance have been sold pursuant to purchase rights exercised under the Amended and Restated ESPP. Under the Amended and Restated ESPP, eligible employees have the right to purchase shares of common stock at the lesser of (i) 85% of the last reported sale price of our common stock on the first business day of the offering period, or (ii) 85% of the last reported sale price of the common stock on the last business day of the offering period, in either case rounded up to avoid impermissible trading fractions. Shares issued pursuant to the ESPP contain a legend restricting the transfer or sale of such common stock for a period of 0.5 year after the date of purchase. The ESPP activity for the years ended October 31, 2023, 2022 and 2021 was de minimis. Long-Term Incentive Plans The Company’s Board of Directors (the “Board”) periodically approves Long Term Incentive Plans which include performance-based awards tied to the Company’s common stock price as well as time-vesting awards. None of the awards granted as part of Long-Term Incentive Plans include any dividend equivalent or other stockholder rights. To the extent the awards are earned, they may be settled in shares or cash of an equivalent value at the Company’s option. These plans are further described below. Fiscal Year 2023 Long-Term Incentive Plan: On December 5, 2022, the Board approved a Long-Term Incentive Plan for fiscal year 2023 (the “FY 2023 LTI Plan”) as a sub-plan consisting of awards made under the 2018 Incentive Plan. The participants in the FY 2023 LTI Plan are members of senior management. The FY 2023 LTI Plan consists of two award components: 1) Relative Total Shareholder Return (“TSR”) Performance Share Units (“PSU”). The PSUs granted during the year ended October 31, 2023 will be earned over the performance period ending on October 31, 2025, but will remain subject to a continued service-based vesting requirement until the third anniversary of the date of grant. The performance measure for the relative TSR PSUs is the TSR of the Company relative to the TSR of the Russell 2000 from November 1, 2022 through October 31, 2025. The Compensation Committee of the Board established the performance assessment criteria for the relative TSR PSUs as the TSR of the Company relative to the TSR of the Russell 2000, with the award calibration being 100% plus or minus 0.5 x the difference between the Company’s TSR and the Russell 2000 Index composite TSR. The award is capped at 200% of the target number of PSUs, and the award is further capped at 100% of the target number of PSUs if the Company’s absolute TSR over the performance period is negative. The Company’s TSR is calculated by subtracting the Company’s beginning stock price (defined as the average closing price of the Company’s common stock over the 60 consecutive trading days ending on October 31, 2022) from the ending stock price (defined as the average closing price of the Company’s common stock over the 60 consecutive trading days ending on October 31, 2025), adding any dividends during the period, and then dividing the result by the Company’s beginning stock price. Given that the performance period is still open, the Company has reserved shares equal to 200% of the target number of PSUs, subject to performance during the remaining performance period as well as vesting based on continued service until December 5, 2025 (the third anniversary of the grant date). 2) Time-vesting RSUs. The time-vesting RSUs granted during the year ended October 31, 2023 will vest at a rate of one -third of the total number of RSUs on each of the first three anniversaries of the date of grant. Fiscal Year 2022 Long Term Incentive Plan: On December 10, 2021, the Board approved a Long-Term Incentive Plan for fiscal year 2022 (the “FY 2022 LTI Plan”) as a sub-plan consisting of awards made under the 2018 Incentive Plan. The participants in the FY 2022 LTI Plan are members of senior management. The FY 2022 LTI Plan consists of two award components: 1) Relative TSR PSU awards. The PSUs granted during the year ended October 31, 2022 will be earned over the performance period ending on October 31, 2024, but will remain subject to a continued service-based vesting requirement until the third anniversary of the date of grant. The performance measure for the relative TSR performance units is the TSR of the Company relative to the TSR of the Russell 2000 from November 1, 2021 through October 31, 2024. The Compensation Committee established the performance assessment criteria for the relative TSR PSUs as the TSR of the Company relative to the TSR of the Russell 2000, with the award calibration being 100% plus or minus 0.5 x the difference between the Company’s TSR and the Russell 2000 Index composite TSR. The award is capped at 200% of the target number of PSUs, and the award is further capped at 100% of the target number of PSUs if the Company’s absolute TSR over the performance period is negative. The Company’s TSR is calculated by subtracting the Company’s beginning stock price (defined as the average closing price of the Company’s common stock over the 20 consecutive trading days ending on October 31, 2021) from the ending stock price (defined as the average closing price of the Company’s common stock over the 20 consecutive trading days ending on October 31, 2024), adding any dividends during the period, and then dividing the result by the Company’s beginning stock price. Given that the performance period is still open, the Company has reserved shares equal to 200% of the target number of PSUs, subject to performance during the remaining performance period as well as vesting based on continued service until December 10, 2024 (the third anniversary of the grant date). 2) Time-vesting restricted stock units. The time-vesting RSUs granted during the year ended October 31, 2022 will vest at a rate of one -third of the total number of RSUs on each of the first three anniversaries of the date of grant. Fiscal Year 2021 Long Term Incentive Plan: On November 24, 2020, the Board approved a Long-Term Incentive Plan for fiscal year 2021 (the “FY 2021 LTI Plan”) as a sub-plan consisting of awards made under the 2018 Incentive Plan. The participants in the FY 2021 LTI Plan are members of senior management. The FY 2021 LTI Plan consists of three award components: 1) Relative TSR PSU awards. The PSUs granted during the year ended October 31, 2021 were earned over the performance period ended on October 31, 2023, but remained subject to a continued service-based vesting requirement until the third anniversary of the date of grant (November 24, 2023). The performance measure for the relative TSR PSUs was the TSR of the Company relative to the TSR of the Russell 2000 from November 1, 2020 through October 31, 2023. The Compensation Committee established the performance assessment criteria for the relative TSR PSUs as the TSR of the Company relative to the TSR of the Russell 2000, with the award calibration being 100% plus or minus 0.5 x the difference between the Company’s TSR and the Russell 2000 Index composite TSR. The award was capped at 200% of the target number of PSUs, and the award was further capped at 100% of the target number of PSUs if the Company’s absolute TSR over the performance period was negative. The Company’s TSR was calculated by subtracting the Company’s beginning stock price (defined as the average closing price of the Company’s common stock over the 20 consecutive trading days ending on October 30, 2020) from the ending stock price (defined as the average closing price of the Company’s common stock over the 20 consecutive trading days ending on October 31, 2023), adding any dividends during the period, and then dividing the result by the Company’s beginning stock price. On November 17, 2023, based on the calculations described above, the Compensation Committee certified awards at 73.541% of the target amount, subject to continued service until November 24, 2023 (the third anniversary of the grant date). 2) Absolute TSR PSU awards. The performance measure for the absolute TSR PSUs was an increase in the Company’s stock price during the performance period of November 1, 2020 through October 31, 2023, with the award calibration being based on a specified percentage increase in the price of the Company’s common stock over the average closing price of the Company’s common stock over the 20 consecutive trading days ending on October 30, 2020, which was $2.27 . Specifically, a 25% increase would earn 50% of the target award, a 50% increase would earn 100% of the target award and a 100% increase would earn 200% of the target award. Each price hurdle was required to be met and was met for 20 consecutive trading days during the performance period. The Compensation Committee certified achievement of a 150% increase during fiscal year 2021, resulting in an award percentage of 200% . As a result, the Company reserved shares equal to 200% of the target number of PSUs, subject to continued service until November 24, 2023 (the third anniversary of the grant date). 3) Time-vesting restricted stock units. The time-vesting RSUs granted during the year ended October 31, 2021 vest at a rate of one -third of the total number of RSUs on each of the first three anniversaries of the date of grant. Other Equity Incentive Plans The Company’s 2006 and 2010 Equity Incentive Plans remain in effect only to the extent of awards outstanding under the plans as of October 31, 2023. Share-Based Compensation Share-based compensation was reflected in the Consolidated Statements of Operations and Comprehensive Loss as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended October 31, ​ 2023 2022 ​ 2021 Cost of revenues ​ $ 1,502 ​ $ 706 ​ $ 493 Administrative and selling expense ​ ​ 8,657 ​ ​ 5,418 ​ ​ 3,593 Research and development expense ​ ​ 1,429 ​ ​ 456 ​ ​ 111 ​ ​ $ 11,588 ​ $ 6,580 ​ $ 4,197 ​ Restricted Stock Units Including Performance Based Awards The following table summarizes our RSU and PSU activity for the year ended October 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ Restricted Stock Units ​ Shares Weighted-Average Fair Value Outstanding as of October 31, 2022 ​ ​ 2,520,881 ​ $ 7.93 Granted - PSUs ​ ​ 1,124,953 ​ ​ 5.50 Granted - time-vesting RSUs ​ ​ 4,538,236 ​ ​ 3.36 Vested ​ ​ (1,207,881) ​ ​ 5.39 Forfeited ​ ​ (433,051) ​ ​ 5.01 Outstanding as of October 31, 2023 ​ ​ 6,543,138 ​ $ 5.06 ​ On December 5, 2022, 2,249,890 RSUs were awarded to senior management under the FY 2023 LTI Plan, which included 1,124,953 PSUs and 1,124,937 time-based vesting RSUs. The PSUs were valued based on a Monte-Carlo Simulation, and the estimated fair value of the relative TSR PSUs was $5.50 per share. The PSUs and time-based vesting RSUs are expensed over the three-year service period. In addition to the awards granted to senior management, during the year ended October 31, 2023, the Board also granted a total of 3,413,299 time-based vesting RSU awards to certain salaried employees to promote ownership of the Company’s equity and retention. The time-based vesting RSUs granted during the year ended October 31, 2023 vest at a rate of one PSUs are issued assuming participants achieve 100% target performance. The Company also reserves additional shares assuming the maximum performance targets are met. As of October 31, 2023, the Company had reserved an additional 210,190 shares for potential issuance under the FY 2021 LTI Plan, an additional 175,548 shares for potential issuance under the FY 2022 LTI Plan and an additional 1,095,657 shares for potential issuance under the FY 2023 LTI Plan. RSU and PSU expense is based on the fair value of the award at the date of grant and is amortized over the vesting period, which is generally over 3 or 4 years. As of October 31, 2023, total unrecognized compensation cost related to RSUs and PSUs was $17.0 million, which is expected to be recognized over approximately the next two years on a weighted-average basis. Stock Awards During the years ended October 31, 2023, 2022 and 2021, we awarded 103,631, 76,848 and 31,889 shares, respectively, of fully vested, unrestricted common stock to the independent members of our Board as a component of Board compensation, which resulted in recognizing $0.2 million, $0.2 million and $0.3 million of expense for the years ended October 31, 2023, 2022 and 2021, respectively. Employee Tax-Deferred Savings Plans We offer a 401(k) plan (the “401(k) Plan”) to all full time employees that provides for tax-deferred salary deductions for eligible employees (beginning the first month following an employee’s hire date). Employees may choose to make voluntary contributions of their annual compensation to the 401(k) Plan, limited to an annual maximum amount as set periodically by the U.S. Internal Revenue Service (“IRS”). Employee contributions are fully vested when made. Under the 401(k) Plan, there is no option available to the employee to receive or purchase our common stock. Matching contributions of 2% under the 401(k) Plan aggregated $1.1 million, $0.5 million, and $0.4 million for the years ended October 31, 2023, 2022, and 2021, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Oct. 31, 2023
Income Taxes
Income Taxes	Note 16. Income Taxes The components of loss before income taxes for the years ended October 31, 2023, 2022, and 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 U.S. ​ $ (95,910) ​ $ (145,439) ​ $ (96,959) Foreign ​ (11,565) ​ (974) ​ (4,064) Loss before income taxes ​ $ (107,475) ​ $ (146,413) ​ $ (101,023) ​ The Company recorded an income tax provision totaling $0.6 million, $0.8 million and $0 for the years ended October 31, 2023, 2022 and 2021, respectively. The income tax expense primarily relates to foreign income taxes in South Korea. Franchise tax expense, which is included in administrative and selling expenses, was $0.9 million, $1.0 million and $0.5 million for the years ended October 31, 2023, 2022 and 2021, respectively. The reconciliation of the federal statutory income tax rate to our effective income tax rate for the years ended October 31, 2023, 2022 and 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 Statutory federal income tax rate (21.0) % (21.0) % (21.0) % Increase (decrease) in income taxes resulting from: ​ ​ ​ ​ ​ State taxes, net of Federal benefits (3.2) % (3.6) % (5.2) % Foreign withholding tax 0.5 % 0.6 % 0.2 % Net operating loss expiration, impairment and true-ups 6.1 % 8.7 % 3.6 % Nondeductible expenditures 2.1 % 1.4 % 1.9 % Change in tax rates 2.8 % 0.3 % (1.3) % Fair value adjustment on warrants — % — % 3.3 % Other, net 0.6 % 0.7 % — % Deferred only adjustment (0.1) % (0.1) % 0.8 % Valuation allowance 12.7 % 13.6 % 17.9 % Effective income tax rate 0.5 % 0.6 % 0.2 % ​ Our deferred tax assets and liabilities consisted of the following as of October 31, 2023 and 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 Deferred tax assets: ​ ​ Compensation and benefit accruals ​ $ 6,026 ​ $ 8,523 Bad debt and other allowances ​ 1,945 ​ 2,453 Capital loss and tax credit carry-forwards ​ 14,701 ​ 14,310 Net operating losses (domestic and foreign) ​ 139,900 ​ 123,825 Deferred license revenue ​ 1,148 ​ 1,548 Accumulated depreciation ​ 14,051 ​ 20,229 Grant revenue ​ 323 ​ 475 Excess business interest ​ 6,406 ​ 10,424 Operating lease liabilities ​ 1,879 ​ 2,085 Capitalized research and development ​ ​ 9,729 ​ ​ — Mark-to-market ​ ​ 987 ​ ​ — Other ​ 4 ​ — Gross deferred tax assets: ​ 197,099 ​ 183,872 Valuation allowance ​ (193,477) ​ (180,048) Deferred tax assets after valuation allowance ​ 3,622 ​ 3,824 Deferred tax liability: ​ ​ ​ ​ In process research and development ​ (2,293) ​ (2,475) Right of use assets ​ (1,600) ​ (1,809) Other ​ (9) ​ — Net deferred tax liability ​ $ (280) ​ $ (460) ​ We continually evaluate our deferred tax assets as to whether it is “more likely than not” that the deferred tax assets will be realized. In assessing the realizability of our deferred tax assets, management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies. Based on the projections for future taxable income over the periods in which the deferred tax assets are realizable, management believes the deferred tax assets are not more likely than not to be realized. As a result, we recorded a valuation allowance against our net deferred tax assets. As of October 31, 2023, we had $481.5 million of federal net operating loss (“NOL”) carryforwards that expire in the years 2024 to 2038 and $516.4 million of state NOL carryforwards that expire in the years 2024 through 2041. Additionally, we had $11.7 million of state tax credits available that will expire from tax years 2024 to 2040. During the 2020 tax year, the Company experienced an “ownership change” as defined by Internal Revenue Code Section 382. As a result, the utilization of federal and state NOLs generated prior to October of 2020 is subject to limitation and a reduction was made in fiscal year 2020 to the carrying balance of the federal and state NOLs to reflect the future limitation on utilization. The Company has updated its analysis of potential ownership changes through October 31, 2023 and concluded that no additional ownership changes have occurred subsequent to October 2020. In addition, the acquisition of Versa Inc. in fiscal year 2013 triggered a Section 382 ownership change at the level of Versa Inc. which will limit the future usage of some of the federal and state NOLs that we acquired in that transaction. Accordingly, a valuation allowance has been recorded against the deferred tax asset associated with these attributes to reflect the future limitation on utilization. The Company’s financial statements reflect expected future tax consequences of uncertain tax positions that the Company has taken or expects to take on a tax return (including a decision whether to file or not file a return in a particular jurisdiction) presuming the taxing authorities’ full knowledge of the position and all relevant facts. The Company did not have any unrecognized tax benefits as of October 31, 2023 and 2022. It is our policy to record interest and penalties on unrecognized tax benefits as income taxes; however, because of our significant NOLs, no provision for interest or penalties has been recorded. We file income tax returns in the U.S. and certain states, primarily Connecticut and California, as well as income tax returns required internationally for South Korea and Germany. We are open to examination by the IRS and various states in which we file for fiscal year 2003 to the present.

Loss Per Share

Loss Per Share	12 Months Ended
	Oct. 31, 2023
Loss Per Share
Loss Per Share	Note 17. Loss Per Share Basic earnings (loss) per common share (“EPS”) are generally calculated as income (loss) available to common stockholders divided by the weighted average number of common shares outstanding. Diluted EPS is generally calculated as income (loss) available to common stockholders divided by the weighted average number of common shares outstanding plus the dilutive effect of common share equivalents. The calculation of basic and diluted EPS for the years ended October 31, 2023, 2022 and 2021 was as follows (amounts in thousands, except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended October 31, ​ ​ 2023 ​ ​ 2022 2021 Numerator ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to FuelCell Energy, Inc. ​ $ (107,568) ​ $ (142,722) ​ $ (101,055) ​ Series B preferred stock dividends ​ ​ (3,200) ​ ​ (3,200) ​ ​ (3,200) ​ Net loss attributable to common stockholders ​ $ (110,768) ​ $ (145,922) ​ $ (104,255) ​ Denominator ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding – basic ​ ​ 419,747,796 ​ ​ 383,139,140 ​ ​ 334,742,346 ​ Effect of dilutive securities (1) ​ ​ — ​ ​ — ​ ​ — ​ Weighted average common shares outstanding – diluted ​ ​ 419,747,796 ​ ​ 383,139,140 ​ ​ 334,742,346 ​ Net loss to common stockholders per share – basic ​ $ (0.26) ​ $ (0.38) ​ $ (0.31) ​ Net loss to common stockholders per share – diluted (1) ​ $ (0.26) ​ $ (0.38) ​ $ (0.31) ​ (1) Due to the net loss to common stockholders in each of the years presented above, diluted earnings per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive. As of October 31, 2023, 2022 and 2021, potentially dilutive securities excluded from the diluted loss per share calculation are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ October 31, ​ 2023 2022 ​ 2021 May 2017 Offering – Series C Warrants ​ ​ - ​ ​ - ​ ​ 950,102 Outstanding options to purchase common stock ​ ​ 18,291 ​ ​ 20,231 ​ ​ 22,388 Unvested Restricted Stock Units ​ ​ 6,543,138 ​ ​ 2,520,881 ​ ​ 2,543,541 5% Series B Cumulative Convertible Perpetual Preferred Stock ​ ​ 37,837 ​ ​ 37,837 ​ ​ 37,837 Total potentially dilutive securities ​ ​ 6,599,266 ​ ​ 2,578,949 ​ ​ 3,553,868 ​

Restricted Cash

Restricted Cash	12 Months Ended
	Oct. 31, 2023
Restricted Cash
Restricted Cash	Note 18. Restricted Cash As of October 31, 2023 and 2022, there was $49.6 million and $23.0 million, respectively, of restricted cash and cash equivalents pledged as performance security, reserved for future debt service requirements, and reserved for letters of credit for certain banking requirements and contracts. The allocation of restricted cash is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Cash Restricted for Outstanding Letters of Credit (1) ​ $ 14,152 ​ $ 4,993 Cash Restricted for PNC Sale-Leaseback Transactions ​ ​ — ​ ​ 5,010 Cash Restricted for Crestmark Sale-Leaseback Transactions ​ ​ 2,901 ​ ​ 2,894 Bridgeport Fuel Cell Park Project Debt Service and Performance Reserves ​ ​ — ​ ​ 8,746 Debt Service and Performance Reserves related to OpCo Financing Facility ​ ​ 19,698 ​ ​ — Debt Service and Performance Reserves related to the Senior and Subordinated Back Leverage Loan Facilities ​ ​ 9,294 ​ ​ — Other ​ ​ 3,579 ​ ​ 1,346 Total Restricted Cash ​ ​ 49,624 ​ ​ 22,989 Restricted Cash and Cash Equivalents – Short-Term (2) ​ ​ (5,159) ​ ​ (4,423) Restricted Cash and Cash Equivalents – Long-Term ​ $ 44,465 ​ $ 18,566 (1) Letters of credit outstanding as of October 31, 2023 expire on various dates through August 2028. (2) Short-term restricted cash and cash equivalents are amounts expected to be released and categorized as unrestricted cash within twelve months of the balance sheet date.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Oct. 31, 2023
Commitments and Contingencies
Commitments and Contingencies	Note 19. Commitments and Contingencies Service Agreements Under the provisions of its service agreements, the Company provides services to maintain, monitor, and repair customer power plants to meet minimum operating levels. Under the terms of such service agreements, the particular power plant must meet a minimum operating output during defined periods of the term. If minimum output falls below the contract requirement, the Company may be subject to performance penalties and/or may be required to repair or replace the customer’s fuel cell module(s). Power Purchase Agreements Under the terms of the Company’s PPAs, customers agree to purchase power from the Company’s fuel cell power plants at negotiated rates. Electricity rates are generally a function of the customers’ current and estimated future electricity pricing available from the grid. As owner or lessee of the power plants, the Company is responsible for all operating costs necessary to maintain, monitor and repair the power plants. Under certain agreements, the Company is also responsible for procuring fuel, generally natural gas or biogas, to run the power plants. In addition, under the terms of some of the PPAs, the Company may be subject to a performance penalty if the Company does not meet certain performance requirements. Project Fuel Exposure ​ Certain of our PPAs for project assets in our generation operating portfolio and project assets under construction expose us to fluctuating fuel price risks as well as the risk of being unable to procure the required amounts of fuel and the lack of alternative available fuel sources. We seek to mitigate our fuel risk using strategies including: (i) fuel cost reimbursement mechanisms in our PPAs to allow for pass through of fuel costs (full or partial) where possible, which we have done with our 14.9 MW operating project in Bridgeport, CT; (ii) procuring fuel under fixed price physical supply contracts with investment grade counterparties, which we have done for twenty years for our Tulare BioMAT project, the initial seven years of the eighteen year PPA for our LIPA Yaphank Project, six years of the twenty year PPA for our 14.0 MW Derby project, and the initial two years of the twenty year hydrogen power purchase agreement for our Toyota project; and (iii) potentially entering into future financial hedges with investment grade counterparties to offset potential negative market fluctuations. ​ There are currently three projects with fuel sourcing risk, which are the Toyota project, which requires procurement of RNG, and our Derby, CT 14.0 MW and 2.8 MW projects, both of which require natural gas for which there is no pass-through mechanism. A two-year (through May of 2025) fuel supply contract has been executed for the Toyota project. Six-year (through October 2029) fuel supply contracts have been executed for the 14.0 MW and 2.8 MW projects in Derby, CT. The Company will look to extend the duration of these contracts should market and credit conditions allow. If the Company is unable to secure fuel on favorable economic terms, it may result in impairment charges to the Derby project assets and further charges for the Toyota project asset. ​ The Company recorded a derivative gain during the year ended October 31, 2023 of $4.1 million as a result of net settling certain natural gas purchases under a previous normal purchase normal sale contract designation which resulted in a change to mark-to-market accounting. The Company has recorded the derivative asset within other assets on the Consolidated Balance Sheets. ​ Other As of October 31, 2023, the Company had unconditional purchase commitments aggregating $102.2 million, for materials, supplies and services in the normal course of business. Legal Proceedings From time to time, the Company is involved in legal proceedings, including, but not limited to, regulatory proceedings, claims, mediations, arbitrations and litigation, arising out of the ordinary course of its business (“Legal Proceedings”). Although the Company cannot assure the outcome of such Legal Proceedings, management presently believes that the result of such Legal Proceedings, either individually, or in the aggregate, will not have a material adverse effect on the Company’s consolidated financial statements, and no material amounts have been accrued in the Company’s consolidated financial statements with respect to these matters.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Oct. 31, 2023
Supplemental Cash Flow Information
Supplemental Cash Flow Information	Note 20. Supplemental Cash Flow Information The following represents supplemental cash flow information (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended October 31, ​ 2023 2022 2021 Cash interest paid ​ $ 3,088 ​ $ 1,556 ​ $ 5,765 Income taxes paid ​ 6 ​ 2 ​ 6 Noncash financing and investing activity: ​ ​ ​ ​ ​ ​ Noncash reclassifications between inventory and project assets ​ 1,987 ​ 1,260 ​ 7,052 Noncash reclassifications from inventory to fixed assets ​ ​ — ​ ​ 1,552 ​ ​ — Noncash reclassifications from other assets to project assets ​ ​ — ​ ​ 2,375 ​ ​ — Director stock compensation ​ 225 ​ 305 ​ 275 Accrued noncontrolling interest distribution ​ ​ 148 ​ ​ — ​ ​ — Addition of operating lease liabilities ​ 1,952 ​ — ​ 1,459 Addition of operating lease right-of-use assets ​ 1,952 ​ — ​ 1,459 Reclassification to equity of warrant liability for warrant exercises ​ — ​ — ​ 21,170 Noncash reduction in basis of project assets ​ ​ 6,330 ​ ​ — ​ ​ — Accrued purchase of fixed assets, cash paid to be paid in subsequent period ​ 1,646 ​ 4,396 ​ 1,537 Accrued purchase of project assets, cash to be paid in subsequent period ​ 4,515 ​ 6,444 ​ 6,707 ​

Nature of Business and Basis of

Nature of Business and Basis of Presentation (Policies)	12 Months Ended
	Oct. 31, 2023
Nature of Business and Basis of Presentation
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation Headquartered in Danbury, Connecticut, FuelCell Energy, Inc. (together with its subsidiaries, the “Company” “FuelCell Energy,” “we,” “us,” or “our”) is a global leader in delivering environmentally responsible distributed baseload energy platform solutions through our proprietary fuel cell technology. Today, we offer commercial technology that produces clean electricity, heat, clean hydrogen, and water and is also capable of recovering and capturing carbon for utilization and/or sequestration, depending on product configuration and application. We also continue to invest in product development and commercializing technologies that are expected to add new capabilities to our platforms’ abilities to deliver hydrogen and long duration hydrogen-based energy storage through our solid oxide technologies, as well as further enhance our existing platforms’ carbon capture solutions. ​ FuelCell Energy is focused on advancing sustainable clean energy technologies that address some of the world’s most critical challenges around energy access, security, resilience, reliability, affordability, safety and environmental stewardship. As a leading global manufacturer of proprietary fuel cell technology platforms, FuelCell Energy is uniquely positioned to serve customers worldwide with sustainable products and solutions for industrial and commercial businesses, utilities, governments, municipalities, and communities. ​ The consolidated financial statements include our accounts, those of our wholly-owned subsidiaries, and those of our consolidated variable interest entities. All intercompany accounts and transactions have been eliminated. Certain reclassifications have been made to the prior year amounts to conform to the presentation for the year ended October 31, 2023. Interest income for the years ended October 31, 2022 and 2021, which was previously included within Other income (expense), net has been reclassified to Interest income in the Consolidated Statements of Operations and Comprehensive Loss.
Liquidity	Liquidity Our principal sources of cash have been proceeds from the sale of our products and projects, electricity generation revenues, research and development and service agreements with third parties, sales of our common stock through public equity offerings, and proceeds from debt, project financing and tax monetization transactions. We have utilized this cash to accelerate the commercialization of our solid oxide platforms, develop new capabilities to separate and capture carbon, develop and construct project assets, invest in capital improvements and expansion of our operations, perform research and development, pay down existing outstanding indebtedness, and meet our other cash and liquidity needs. As of October 31, 2023, unrestricted cash and cash equivalents totaled $250.0 million compared to $458.1 million as of October 31, 2022. During the year ended October 31, 2023, the Company invested in United States (U.S.) Treasury Securities. The amortized cost of the U.S. Treasury Securities outstanding totaled $103.8 million as of October 31, 2023 compared to $0 as of October 31, 2022 and is classified as Investments - short-term on the Consolidated Balance Sheets. The maturity dates for the outstanding U.S. Treasury Securities range from November 9, 2023 to January 23, 2024. The Company, from time to time, offers and sells shares under its Open Market Sale Agreement (as defined in Note 12. “Stockholders’ Equity and Warrant Liabilities”). During the fiscal year ended October 31, 2023, approximately 44.3 million shares were sold under the Open Market Sale Agreement resulting in gross proceeds of approximately $99.7 million. See Note 12. “Stockholders’ Equity and Warrant Liabilities” for additional information regarding the Open Market Sale Agreement. ​ During the third quarter of fiscal year 2023, the Company (through one of its indirect subsidiaries) entered into a project financing facility (which is referred to as the “OpCo Financing Facility”) in the amount of $80.5 million, which was partially used to extinguish certain existing debt, to partially repay other existing debt, and to repurchase project assets under sale-leaseback transactions, resulting in $46.1 million of net proceeds. See Note 11. “Debt” for additional information regarding the OpCo Financing Facility. ​ During the fourth quarter of fiscal year 2023, the Company (through one of its indirect subsidiaries) entered into two related term loan facilities (which are referred to herein as the “Senior Back Leverage Loan Facility” and the “Subordinated Back Leverage Loan Facility”) in the aggregate amount of $20.0 million. See Note 11. “Debt” for additional information regarding the Senior Back Leverage Loan Facility and the Subordinated Back Leverage Loan Facility . ​ During the fourth quarter of fiscal year 2023, the Company closed on a tax equity financing transaction with Franklin Park 2023 FCE Tax Equity Fund, LLC (“Franklin Park”), a subsidiary of Franklin Park Infrastructure, LLC, for two fuel cell power plant installations -- the 14.0 MW Derby Fuel Cell Project and the 2.8 MW SCEF Fuel Cell Project, both located in Derby, Connecticut (collectively the “Derby Projects”). Franklin Park’s tax equity commitment with respect to the Derby Projects totals $30.2 million. Of this amount, approximately $9.1 million was received on October 31, 2023. In connection with the closing of this tax equity financing transaction, the Company paid closing costs of approximately $1.8 million, which included appraisal fees, title insurance expenses and legal and consulting fees. The balance of this commitment will be funded to the Company upon substantial completion of the Derby Projects. Net of estimated additional fees of $0.5 million, the Company anticipates additional funding of approximately $20.6 million. We believe that our unrestricted cash and cash equivalents, expected receipts from our contracted backlog, funds received upon the maturity of U.S. Treasury Securities, and release of short-term restricted cash less expected disbursements over the next twelve months will be sufficient to allow the Company to meet its obligations for at least one year from the date of issuance of these financial statements. ​ To date, we have not achieved profitable operations or sustained positive cash flow from operations. The Company’s future liquidity, for fiscal year 2024 and in the long-term, will depend on its ability to (i) timely complete current projects in process within budget, (ii) increase cash flows from its generation operating portfolio, including by meeting conditions required to timely commence operation of new projects, operating its generation operating portfolio in compliance with minimum performance guarantees and operating its generation operating portfolio in accordance with revenue expectations, (iii) obtain financing for project construction and manufacturing expansion, (iv) obtain permanent financing for its projects once constructed, (v) increase order and contract volumes, which would lead to additional product sales, service agreements and generation revenues, (vi) obtain funding for and receive payment for research and development under current and future Advanced Technologies contracts, (vii) successfully commercialize its solid oxide, hydrogen and carbon capture platforms, (viii) implement capacity expansion for solid oxide product manufacturing, (ix) implement the product cost reductions necessary to achieve profitable operations, (x) manage working capital and the Company’s unrestricted cash balance and (xi) access the capital markets to raise funds through the sale of debt and equity securities, convertible notes, and other equity-linked instruments. We are continually assessing different means by which to accelerate the Company’s growth, enter new markets, commercialize new products, and enable capacity expansion. Therefore, from time to time, the Company may consider and enter into agreements for one or more of the following: negotiated financial transactions, minority investments, collaborative ventures, technology sharing, transfer or other technology license arrangements, joint ventures, partnerships, acquisitions or other business transactions for the purpose(s) of geographic or manufacturing expansion and/or new product or technology development and commercialization, including hydrogen production through our carbonate and solid oxide platforms and storage and carbon capture, sequestration and utilization technologies. Our business model requires substantial outside financing arrangements and satisfaction of the conditions of such arrangements to construct and deploy our projects to facilitate the growth of our business. The Company has invested capital raised from sales of its common stock to build out its project portfolio. The Company has also utilized and expects to continue to utilize a combination of long-term debt and tax equity financing (e.g., sale-leaseback transactions, partnership flip transactions and the monetization and/or transfer of eligible investment and production tax credits) to finance its project asset portfolio as these projects commence commercial operations, particularly in light of the passage of the Inflation Reduction Act in August 2022. The Company may also seek to undertake private placements of debt securities to finance its project asset portfolio. The proceeds of any such financing, if obtained, may allow the Company to reinvest capital back into the business and to fund other projects. We may also seek to obtain additional financing in both the debt and equity markets in the future. If financing is not available to us on acceptable terms if and when needed, or on terms acceptable to us or our lenders, if we do not satisfy the conditions of our financing arrangements, if we spend more than the financing approved for projects, if project costs exceed an amount that the Company can finance, or if we do not generate sufficient revenues or obtain capital sufficient for our corporate needs, we may be required to reduce or slow planned spending, reduce staffing, sell assets, seek alternative financing and take other measures, any of which could have a material adverse effect on our financial condition and operations .
Cash and Cash Equivalents	Cash and Cash Equivalents All cash equivalents consist of investments in money market funds with original maturities of three months or less at the date of acquisition. We place our temporary cash equivalent investments with high credit quality financial institutions.
Inventories and Advance Payments to Vendors	Inventories and Advance Payments to Vendors Inventories consist principally of raw materials and work-in-process. Cost is determined using the first-in, first-out cost method. Included in our inventory balance are used modules that are brought back into inventory upon installation of new modules. When a new module is installed, a determination is made as to whether the used module has remaining useful life or should be scrapped and materials recycled. Modules that are deemed to have remaining useful life are put into inventory at an estimated value based on the expected remaining life of the module and its projected output. In certain circumstances, we will make advance payments to vendors for future inventory deliveries. These advance payments are recorded as Other current assets on the Consolidated Balance Sheets. Inventories are reviewed to determine net realizable value. This review includes analyzing inventory levels of individual parts considering the current design of our products and production requirements as well as the expected inventory requirements for maintenance on installed power platforms.
Investments - Short-Term	Investments – Short-Term The Company invests in U.S. Treasury Securities which are held-to-maturity and are recorded at amortized cost.
Allowance for Doubtful Accounts and Credit Losses	Allowance for Doubtful Accounts and Credit Losses The Company had no allowance for doubtful accounts or credit losses as of October 31, 2023 and 2022. Uncollectible accounts receivable are charged against the allowance for doubtful accounts when all collection efforts have failed and it is deemed unlikely that the amount will be recovered. The Company would record a specific reserve for individual accounts when the Company becomes aware of specific customer circumstances such as in the case of a bankruptcy filing or the deterioration in the customer’s operating results or financial position.
Project Assets	Project Assets Project assets consist of capitalized costs for fuel cell projects in various stages of development, including those projects with respect to which we have entered into power purchase agreements (“PPAs”) and those projects with respect to which we expect to secure long-term contracts. Such development costs are generally incurred prior to entering into a definitive sales or long-term financing agreement for the project. Project assets also include capitalized costs for fuel cell projects which are the subject of sale-leaseback transactions with Crestmark Equipment Finance, a division of MetaBank (“Crestmark”). Project asset costs include costs for developing and constructing a complete turn-key fuel cell project. Development costs can include legal, consulting, permitting, interconnect, and other similar costs. To the extent we enter into a definitive sales agreement, we expense project assets to cost of sales after the respective project asset is sold to a customer and all revenue recognition criteria have been met.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost, less accumulated depreciation which is recorded based on the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are amortized on the straight-line method over the shorter of the estimated useful lives of the assets or the term of the lease. When property, plant or equipment is sold or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in operations for the period.
Goodwill and Indefinite-Lived Intangibles	Goodwill and Indefinite-Lived Intangibles Goodwill represents the excess of the aggregate purchase price over the fair value of the net assets acquired in a business combination and is reviewed for impairment at least annually. The intangible asset represents indefinite-lived in-process research and development (“IPR&D”) for cumulative research and development efforts associated with the development of solid oxide fuel cell stationary power generation and is also reviewed at least annually for impairment. Accounting Standards Codification (“ASC”) Topic 350: Intangibles - Goodwill and Other The Company completed its annual impairment analysis of goodwill and IPR&D as of July 31, 2023. The goodwill and IPR&D asset are both held by the Company’s Versa Power Systems, Inc. (“Versa Inc.”) reporting unit. Goodwill and the IPR&D asset are also reviewed for possible impairment whenever changes in conditions indicate that the fair value of a reporting unit or IPR&D asset is more likely than not below its respective carrying value. No impairment charges were recorded with respect to goodwill or the IPR&D asset during the fiscal years ended October 31, 2023, 2022 and 2021.
Impairment of Long-Lived Assets (including Project Assets)	Impairment of Long-Lived Assets (including Project Assets) Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. If events or changes in circumstances indicate that the carrying amount of the asset group may not be recoverable, we compare the carrying amount of the asset group to the future undiscounted net cash flows, excluding debt service costs, expected to be generated by the asset group and its ultimate disposition. If the sum of the undiscounted cash flows is less than the carrying value, the impairment to be recognized is measured by the amount by which the carrying amount of the asset group exceeds its fair value.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in accordance with ASC Topic 606: Revenue from Contracts with Customers A contract is accounted for when there has been approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Performance obligations under a contract are identified based on the goods or services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. In certain instances, the Company has concluded distinct goods or services should be accounted for as a single performance obligation that is a series of distinct goods or services that have the same pattern of transfer to the customer. To the extent a contract includes multiple promised goods or services, the Company must apply judgment to determine whether the customer can benefit from the goods or services either on their own or together with other resources that are readily available to the customer (the goods or services are capable of being distinct) and if the promise to transfer the goods or services to the customer is separately identifiable from other promises in the contract (the goods or services are distinct in the context of the contract). If these criteria are not met, the promised goods or services are accounted for as a single performance obligation. The transaction price is determined based on the consideration that the Company will be entitled to in exchange for transferring goods or services to the customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price, generally utilizing the expected value method. Determining the transaction price requires judgment. If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price basis. Standalone selling price is determined by the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price by taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. Performance obligations are satisfied either over time or at a point in time as discussed in further detail below. In addition, the Company’s contracts with customers generally do not include significant financing components or non-cash consideration. The Company has elected practical expedients in the accounting guidance that allow for revenue to be recorded in the amount that the Company has a right to invoice, if that amount corresponds directly with the value to the customer of the Company’s performance to date, and that allow the Company not to disclose related unsatisfied performance obligations. The Company records any amounts that are billed to customers in excess of revenue recognized as deferred revenue and revenue recognized in excess of amounts billed to customers as unbilled receivables. Revenue streams are classified as follows: Product. Service. Generation. Advanced Technologies. See below for a discussion of revenue recognition under ASC 606 by disaggregated revenue stream. Completed project assets Contracts for the sale of completed project assets include the sale of the project asset, the assignment of the service agreement, and the assignment of the PPA. The relative stand-alone selling price is estimated and is used as the basis for allocation of the contract consideration. Revenue is recognized upon the satisfaction of the performance obligations, which includes the transfer of control of the project asset to the customer, which is when the contract is signed and the PPA is assigned to the customer. See below for further discussion regarding revenue recognition for service agreements. Contractual payments related to the sale of the project asset and assignment of the PPA are generally received up-front. Payment terms for service agreements are generally ratable over the term of the agreement. Module sales Contracts for module sales represent the sale of a completed fuel cell module at a contracted selling price. These contracts are on a per unit basis and revenue is recognized as each unit is completed and ready to ship and the performance obligation is satisfied. Payment terms for module sales are generally based on milestones achieved through the manufacturing timeline of the module. Service agreements Service agreements represent a single performance obligation whereby the Company performs all required maintenance and monitoring functions, including replacement of modules, to ensure the power platform(s) under the service agreement generate a minimum power output. To the extent the power platform(s) under service agreements do not achieve the minimum power output, certain service agreements include a performance guarantee penalty. Performance guarantee penalties represent variable consideration, which is estimated for each service agreement based on past experience, using the expected value method. The consideration for each service agreement is recognized over time using costs incurred to date relative to total estimated costs at completion to measure progress. The Company reviews its cost estimates on service agreements on an annual basis and records any changes in estimates on a cumulative catch-up basis. Loss accruals for service agreements are recognized to the extent that the estimated remaining costs to satisfy the performance obligation exceed the estimated remaining unrecognized consideration. Estimated losses are recognized in the period in which losses are identified. Payment terms for service agreements are generally ratable over the term of the agreement. Advanced Technologies contracts Advanced Technologies contracts include the promise to perform research and development services and, as such, this represents one performance obligation. Revenue from most government sponsored Advanced Technologies projects is recognized as direct costs are incurred plus allowable overhead less cost share requirements, if any. Revenue is only recognized to the extent the contracts are funded. Revenue recognition for research performed under the EMTEC Joint Development Agreement (as defined elsewhere herein) falls into the practical expedient category where revenue is recorded consistent with the amounts the Company has the right to invoice. Payments are based on costs incurred for government sponsored Advanced Technologies projects and payments under the EMTEC Joint Development Agreement are based on contractual rates for time spent and material costs incurred. Generation revenue For certain project assets where customers purchase electricity from the Company under PPAs, the Company has determined that these agreements should be accounted for as operating leases pursuant to ASC 842, Leases
Variable Interest Entities and Noncontrolling Interests	Variable Interest Entities and Noncontrolling Interests The Company has entered into tax equity financing transactions with certain participating companies for three partnerships (as further described in Note 3. “Tax Equity Financings and Investment Tax Credit Sale”) as of October 31, 2023. These transactions are structured as “partnership flips.” A “partnership flip” is a structure commonly used by tax equity investors in financing renewable energy projects. The Company has determined, under the power and benefits criterion of ASC 810, Consolidations
Sale-Leaseback Accounting	Sale-Leaseback Accounting The Company, through certain wholly-owned subsidiaries, has entered into sale-leaseback transactions for commissioned project assets where we have entered into a PPA with a customer who is both the site host and end user of the power. Due to the Company not meeting criteria to account for the transfer of the project assets as a sale since the leases include a repurchase right, sale accounting is precluded. Accordingly, the Company uses the financing method to account for these transactions. Under the financing method of accounting for a sale-leaseback, the Company does not derecognize the project assets and does not recognize as revenue any of the sale proceeds received from the lessor that contractually constitutes payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as finance obligations and leaseback payments made by the Company are allocated between interest expense and a reduction to the finance obligation. Interest on the finance obligation is calculated using the Company’s incremental borrowing rate at the inception of the arrangement on the outstanding finance obligation. While we receive financing for the related project asset, we have not recognized revenue on the sale-leaseback transactions. Instead, revenue is recognized with respect to the related PPAs in accordance with the Company’s accounting policies for recognizing generation revenue.
Lease Accounting	Lease Accounting Right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the present value of the Company’s obligation to make lease payments arising from the lease over the lease term at the commencement date of the lease. As most of the Company’s leases do not provide an implicit rate, the Company estimated the incremental borrowing rate based on the information available at the date of adoption in determining the present value of lease payments and used the implicit rate when readily determinable. The Company determined incremental borrowing rates through market sources for secured borrowings including relevant industry rates. The Company’s operating lease ROU assets also include any lease pre-payments and exclude lease incentives. Certain of the Company’s leases include variable payments, which may vary based upon changes in facts or circumstances after the start of the lease. The Company excludes variable payments from lease ROU assets and lease liabilities to the extent not considered in-substance fixed, and instead, expenses variable payments as incurred. Variable lease expense and lease expense for short term contracts are not material components of lease expense. The Company’s leases generally have remaining lease terms of 1 to 26 years, some of which include options to extend leases. The exercise of lease renewal options is at the Company’s sole discretion and the Company’s lease ROU assets and liabilities reflect only the options the Company is reasonably certain that it will exercise. We do not have leases with residual value guarantees or similar covenants.
Service Expense Recognition	Service Expense Recognition We warranty our products for a specific period of time against manufacturing or performance defects. Our U.S. warranty is generally limited to a term of 15 months after shipment or 12 months after acceptance of our products. We accrue for estimated future warranty costs based on historical experience. We also provide for a specific accrual if there is a known issue requiring repair during the warranty period. In addition to the standard product warranty, we have entered into service agreements with certain customers to provide monitoring, maintenance and repair services for fuel cell power platforms. Under the terms of these service agreements, the power platform must meet a minimum operating output during the term. If the minimum output falls below the contract requirement, we may be subject to performance penalties or may be required to repair and/or replace the customer’s fuel cell module(s). The Company records loss accruals for service agreements when the estimated cost of future module exchanges and maintenance and monitoring activities exceeds the remaining unrecognized contract value. Estimates for future costs on service agreements are determined by a number of factors, including the estimated remaining life of the module(s), used replacement modules available and future operating plans for the power platform. Our estimates are performed on a contract by contract basis and include cost assumptions based on what we anticipate the service requirements will be to fulfill obligations for each contract. At the end of our service agreements, customers are expected to either renew the service agreement or, based on the Company’s rights to title of the module, the module will be returned to the Company as the platform is no longer being maintained.
Research and Development Costs	Research and Development Costs We perform both customer-sponsored research and development projects based on contractual agreements with customers and company-sponsored research and development projects. Costs incurred for customer-sponsored projects include manufacturing and engineering labor, applicable overhead expenses, materials to build and test prototype units and other costs associated with customer-sponsored research and development contracts. Costs incurred for customer-sponsored projects are recorded as cost of Advanced Technologies contract revenues in the Consolidated Statements of Operations and Comprehensive Loss. Costs incurred for company-sponsored research and development projects consist primarily of labor, overhead, materials to build and test prototype units and consulting fees. These costs are recorded as research and development expenses in the Consolidated Statements of Operations and Comprehensive Loss.
Concentrations	Concentrations We contract with a concentrated number of customers for the sale of our products, for service agreements, for power purchase agreements and for Advanced Technologies contracts. For the years ended October 31, 2023, 2022 and 2021, our top customers accounted for 68%, 74% and 61%, respectively, of our total annual consolidated revenue. The percent of consolidated revenues from our top customers for the years ended October 31, 2023, 2022 and 2021, respectively, are presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 Korea Southern Power Company (KOSPO) 31 % 6 % 12 % Korea Fuel Cell Co., Ltd (KFC) ​ 16 % 46 % — % Connecticut Light and Power 13 % 14 % 20 % ExxonMobil Technology and Engineering Company (f/k/a ExxonMobil Research and Engineering Company) (EMTEC) 8 % 8 % 29 % Total 68 % 74 % 61 %
Derivatives	Derivatives ​ We do not use derivatives for speculative or trading purposes. The Company has an interest rate swap that is adjusted to fair value on a quarterly basis. The estimated fair value is based on Level 2 inputs including primarily the floating Secured Overnight Financing Rate (“SOFR”) rate available to swap dealers. The valuation methodology involves comparison of (i) the sum of the present value of all quarterly variable rate payments based on a reset rate using the floating SOFR curve and (ii) the sum of the present value of all quarterly fixed rate payments on the notional amount, which is equivalent to the outstanding principal amount of the loan. ​ The Company has recorded a natural gas purchase contract at fair value which was the result of the net settling of certain natural gas purchases under a contract that was previously designated as normal purchase normal sale which resulted in a change to mark-to-market accounting. The fair value will be adjusted on a quarterly basis. The estimated fair value is based on Level 2 inputs including future prices available to commodity brokers and risk-free rates which are based on Federal reserve yields. The valuation methodology involves utilizing the industry-convention energy swap model.
Use of Estimates	Use of Estimates The preparation of financial statements and related disclosures in conformity with accounting principles generally accepted in the U.S. (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Estimates are used in accounting for, among other things, revenue recognition, lease right-of-use assets and liabilities, excess, slow-moving and obsolete inventories, product warranty accruals, loss accruals on service agreements, share-based compensation expense, allowance for doubtful accounts, depreciation and amortization, impairment of goodwill and in-process research and development intangible assets, impairment of long-lived assets (including project assets), valuation of derivatives and contingencies. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Due to the inherent uncertainty involved in making estimates, actual results in future periods may differ from those estimates.
Foreign Currency Translation	Foreign Currency Translation The translation of the financial statements of FCE Korea Ltd., FCES GmbH and Versa Power Systems Ltd. results in translation gains or losses, which are recorded in Accumulated other comprehensive loss within Stockholders’ equity on the accompanying Consolidated Balance Sheets. We are also subject to foreign currency transaction gains and losses as certain transactions are denominated in foreign currencies. We recognized net foreign currency transaction losses of $(0.4) thousand, $(0.9) million and $(0.9) million for the years ended October 31, 2023, 2022 and 2021, respectively. These amounts have been included in Other income (expense), net in the Consolidated Statements of Operations and Comprehensive Loss.
Recently Adopted Accounting Guidance and Recent Accounting Guidance Not Yet Effective	Recently Adopted Accounting Guidance There is no recently adopted accounting guidance applicable to the Company’s financial statements . Recent Accounting Guidance Not Yet Effective In November 2023, the Financial Accounting Standards Board (“FASB”) issued guidance to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. In addition, the guidance enhances interim disclosure requirements, clarifies circumstances in which an entity can disclose multiple segment measures of profit or loss, provides new segment disclosure requirements for entities with a single reportable segment and contains other disclosure requirements. The purpose of the guidance is to enable investors to better understand an entity’s overall performance and assess potential future cash flows. The guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. We are currently evaluating the impact that the new guidance will have on our consolidated financial statements.

Nature of Business, Basis of _2

Nature of Business, Basis of Presentation and Significant Accounting Policies (Tables)	12 Months Ended
	Oct. 31, 2023
Nature of Business and Basis of Presentation
Schedule of percent of consolidated revenues	The percent of consolidated revenues from our top customers for the years ended October 31, 2023, 2022 and 2021, respectively, are presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 Korea Southern Power Company (KOSPO) 31 % 6 % 12 % Korea Fuel Cell Co., Ltd (KFC) ​ 16 % 46 % — % Connecticut Light and Power 13 % 14 % 20 % ExxonMobil Technology and Engineering Company (f/k/a ExxonMobil Research and Engineering Company) (EMTEC) 8 % 8 % 29 % Total 68 % 74 % 61 %

Investments - Short-Term (Table

Investments - Short-Term (Tables)	12 Months Ended
	Oct. 31, 2023
Investments - Short-Term
Schedule of investments in held-to-maturity securities	The following table summarizes the amortized cost basis and fair value (based on quoted market prices) as of October 31, 2023 (in thousands). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Gross unrealized ​ Gross unrealized ​ ​ cost ​ gains ​ losses Fair value U.S. Treasury Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2023 ​ $ 103,760 $ 1 $ — $ 103,761

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Oct. 31, 2023
Inventories
Schedule of components of Inventories	Inventories (short and long-term) as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Raw materials ​ $ 36,200 ​ $ 30,624 Work-in-process (1) ​ ​ 55,585 ​ ​ 67,834 Inventories ​ ​ 91,785 ​ ​ 98,458 Inventories – current ​ ​ (84,456) ​ ​ (90,909) Inventories – long-term (2) ​ $ 7,329 ​ $ 7,549 (1) Work-in-process includes the standard components of inventory used to build the typical modules or module components that are intended to be used in future project asset construction or power platform orders or for use under the Company’s service agreements. (2) Long-term inventory includes modules that are contractually required to be segregated for use as replacement modules for a specific project asset .

Project Assets (Tables)

Project Assets (Tables)	12 Months Ended
	Oct. 31, 2023
Project Assets
Summary of Project Assets	Project assets as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ Estimated ​ 2023 2022 Useful Life Project Assets – Operating ​ $ 213,753 ​ $ 154,736 ​ 4-20 years Accumulated depreciation ​ ​ (46,263) ​ ​ (29,546) ​ ​ Project Assets – Operating, net ​ ​ 167,490 ​ ​ 125,190 ​ ​ Project Assets – Construction in progress ​ ​ 90,576 ​ ​ 107,696 ​ 7-20 years Project Assets, net ​ $ 258,066 ​ $ 232,886 ​ ​

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Oct. 31, 2023
Property, Plant and Equipment.
Schedule of property plant and equipment	Property, plant and equipment as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ Estimated ​ ​ 2023 ​ 2022 ​ Useful Life Land ​ $ 524 ​ $ 524 ​ — Building and improvements ​ 21,430 ​ 21,216 10‑26 years Machinery, equipment and software ​ 136,554 ​ 108,656 3‑8 years Furniture and fixtures ​ 5,211 ​ 4,354 10 years Construction in progress ​ 33,950 ​ 26,484 — ​ ​ 197,669 ​ 161,234 ​ ​ Accumulated depreciation ​ (108,001) ​ (103,097) Property, plant and equipment, net ​ $ 89,668 ​ $ 58,137

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Oct. 31, 2023
Goodwill and Intangible Assets
Summary of Intangible Assets	The following tables summarize the Company’s intangible assets as of October 31, 2023 and 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2023 Gross Amount Accumulated Amortization Net Amount In-Process Research and Development ​ $ 9,592 ​ $ — ​ $ 9,592 Bridgeport PPA ​ ​ 12,320 ​ ​ (5,836) ​ ​ 6,484 Total ​ $ 21,912 ​ $ (5,836) ​ $ 16,076 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of October 31, 2022 Gross Amount Accumulated Amortization Net Amount In-Process Research and Development ​ $ 9,592 ​ $ — ​ $ 9,592 Bridgeport PPA ​ ​ 12,320 ​ ​ (4,539) ​ ​ 7,781 Total ​ $ 21,912 ​ $ (4,539) ​ $ 17,373

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Oct. 31, 2023
Accrued Liabilities
Schedule of Accrued Liabilities	Accrued liabilities as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Accrued payroll and employee benefits (1) ​ $ 7,752 ​ $ 8,534 Consideration payable to a customer (2) ​ ​ 3,958 ​ ​ — Accrued service agreement and PPA costs (3) ​ ​ 10,742 ​ ​ 11,340 Accrued legal, taxes, professional and other ​ ​ 3,861 ​ ​ 7,541 Accrued liabilities ​ $ 26,313 ​ $ 27,415 (1) The balance in this account represents accrued payroll, payroll taxes and accrued bonus for both periods. The decrease in the account balance relates to a decrease in accrued bonus as of October 31, 2023. (2) The balance represents the net amount due to Toyota as an accrued liability which will be reduced over time based on the performance under the terms of the Toyota HPPA. (3) Accrued service agreement costs include loss accruals on service contracts of $9.5 million as of October 31, 2023, which increased from $7.3 million as of October 31, 2022. The increase is the result of changes in estimates regarding timing of future module exchanges and future module replacement costs. The accruals for performance guarantees on service agreements and PPAs decreased from $4.1 million as of October 31, 2022 to $1.2 million as of October 31, 2023 .

Leases (Tables)

Leases (Tables)	12 Months Ended
	Oct. 31, 2023
Leases
Summary of Undiscounted Maturities of Operating Lease and Finance Lease Liabilities	As of October 31, 2023, undiscounted maturities of operating lease and finance lease liabilities are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Leases Finance Leases Due Year 1 ​ $ 1,052 ​ $ 16 Due Year 2 ​ ​ 1,276 ​ ​ — Due Year 3 ​ ​ 1,262 ​ ​ — Due Year 4 ​ ​ 1,292 ​ ​ — Due Year 5 ​ ​ 1,267 ​ ​ — Thereafter ​ ​ 12,718 ​ ​ — Total undiscounted lease payments ​ ​ 18,867 ​ ​ 16 Less imputed interest ​ ​ (9,276) ​ ​ (4) Total discounted lease payments ​ $ 9,591 ​ $ 12 ​

Debt (Tables)

Debt (Tables)	12 Months Ended
	Oct. 31, 2023
Debt
Schedule of Debt	Debt as of October 31, 2023 and 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Connecticut Green Bank Loan ​ $ — ​ $ 4,800 Connecticut Green Bank Loan (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 3,507 Liberty Bank Term Loan Agreement (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 5,382 Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project) ​ ​ — ​ ​ 5,382 Connecticut Green Bank Loan (Subordinated Back Leverage Loan Facility) ​ ​ 8,000 ​ ​ — Liberty Bank Loan (Senior Back Leverage Loan Facility) ​ ​ 5,876 ​ ​ — Amalgamated Bank Loan (Senior Back Leverage Loan Facility) ​ ​ 5,873 ​ ​ — Finance obligation for sale-leaseback transactions ​ ​ 18,814 ​ ​ 56,625 State of Connecticut Loan ​ ​ 6,908 ​ ​ 7,774 Finance lease obligations ​ ​ 12 ​ ​ 57 OpCo Financing Facility ​ ​ 77,510 ​ ​ — Deferred finance costs ​ ​ (3,526) ​ ​ (1,152) Total debt and finance obligations ​ ​ 119,467 ​ ​ 82,375 Current portion of long-term debt and finance obligations ​ ​ (10,067) ​ ​ (13,198) Long-term debt and finance obligations ​ $ 109,400 ​ $ 69,177
Aggregate Annual Principal Payments under Loan Agreements and Finance Lease Obligations	Aggregate annual principal payments under our loan agreements, finance obligation, and finance lease obligations for the years subsequent to October 31, 2023 are as follows (in thousands): ​ ​ ​ ​ ​ Year 1 $ 10,712 Year 2 ​ 12,534 Year 3 ​ 12,475 Year 4 ​ 8,487 Year 5 ​ 9,858 Thereafter (1) ​ 59,858 ​ ​ $ 113,924 (1) The annual principal payments included above only include sale-leaseback payments whereas the difference between debt outstanding as of October 31, 2023 and the annual principal payments represent accreted interest and amounts included in the finance obligation that exceed required principal payments.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Oct. 31, 2023
Segment Information
Revenues By Geographic Area	Revenues, by geographic location (based on the customer’s ordering location) for the years ended October 31, 2023, 2022 and 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 United States ​ $ 63,289 ​ $ 60,290 ​ $ 58,393 South Korea ​ 58,432 ​ 68,341 ​ 8,161 Europe ​ 1,673 ​ 1,853 ​ 3,031 Total ​ $ 123,394 ​ $ 130,484 ​ $ 69,585

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Oct. 31, 2023
Benefit Plans
Schedule of Share-Based Compensation Reflected in Consolidated Statement of Operations and Comprehensive Loss	Share-based compensation was reflected in the Consolidated Statements of Operations and Comprehensive Loss as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended October 31, ​ 2023 2022 ​ 2021 Cost of revenues ​ $ 1,502 ​ $ 706 ​ $ 493 Administrative and selling expense ​ ​ 8,657 ​ ​ 5,418 ​ ​ 3,593 Research and development expense ​ ​ 1,429 ​ ​ 456 ​ ​ 111 ​ ​ $ 11,588 ​ $ 6,580 ​ $ 4,197
Summary of RSA and RSU Activity	The following table summarizes our RSU and PSU activity for the year ended October 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ Restricted Stock Units ​ Shares Weighted-Average Fair Value Outstanding as of October 31, 2022 ​ ​ 2,520,881 ​ $ 7.93 Granted - PSUs ​ ​ 1,124,953 ​ ​ 5.50 Granted - time-vesting RSUs ​ ​ 4,538,236 ​ ​ 3.36 Vested ​ ​ (1,207,881) ​ ​ 5.39 Forfeited ​ ​ (433,051) ​ ​ 5.01 Outstanding as of October 31, 2023 ​ ​ 6,543,138 ​ $ 5.06

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Oct. 31, 2023
Income Taxes
Schedule of Components of Loss Before Income Taxes	The components of loss before income taxes for the years ended October 31, 2023, 2022, and 2021 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 U.S. ​ $ (95,910) ​ $ (145,439) ​ $ (96,959) Foreign ​ (11,565) ​ (974) ​ (4,064) Loss before income taxes ​ $ (107,475) ​ $ (146,413) ​ $ (101,023)
Schedule of Reconciliation of Federal Statutory Income Tax Rate To Effective Income Tax Rate	The reconciliation of the federal statutory income tax rate to our effective income tax rate for the years ended October 31, 2023, 2022 and 2021 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 Statutory federal income tax rate (21.0) % (21.0) % (21.0) % Increase (decrease) in income taxes resulting from: ​ ​ ​ ​ ​ State taxes, net of Federal benefits (3.2) % (3.6) % (5.2) % Foreign withholding tax 0.5 % 0.6 % 0.2 % Net operating loss expiration, impairment and true-ups 6.1 % 8.7 % 3.6 % Nondeductible expenditures 2.1 % 1.4 % 1.9 % Change in tax rates 2.8 % 0.3 % (1.3) % Fair value adjustment on warrants — % — % 3.3 % Other, net 0.6 % 0.7 % — % Deferred only adjustment (0.1) % (0.1) % 0.8 % Valuation allowance 12.7 % 13.6 % 17.9 % Effective income tax rate 0.5 % 0.6 % 0.2 %
Schedule of Deferred Tax Assets and Liabilities	Our deferred tax assets and liabilities consisted of the following as of October 31, 2023 and 2022 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 Deferred tax assets: ​ ​ Compensation and benefit accruals ​ $ 6,026 ​ $ 8,523 Bad debt and other allowances ​ 1,945 ​ 2,453 Capital loss and tax credit carry-forwards ​ 14,701 ​ 14,310 Net operating losses (domestic and foreign) ​ 139,900 ​ 123,825 Deferred license revenue ​ 1,148 ​ 1,548 Accumulated depreciation ​ 14,051 ​ 20,229 Grant revenue ​ 323 ​ 475 Excess business interest ​ 6,406 ​ 10,424 Operating lease liabilities ​ 1,879 ​ 2,085 Capitalized research and development ​ ​ 9,729 ​ ​ — Mark-to-market ​ ​ 987 ​ ​ — Other ​ 4 ​ — Gross deferred tax assets: ​ 197,099 ​ 183,872 Valuation allowance ​ (193,477) ​ (180,048) Deferred tax assets after valuation allowance ​ 3,622 ​ 3,824 Deferred tax liability: ​ ​ ​ ​ In process research and development ​ (2,293) ​ (2,475) Right of use assets ​ (1,600) ​ (1,809) Other ​ (9) ​ — Net deferred tax liability ​ $ (280) ​ $ (460)

Loss Per Share (Tables)

Loss Per Share (Tables)	12 Months Ended
	Oct. 31, 2023
Loss Per Share
Schedule of Calculation of Basic and Diluted Loss Per Share	The calculation of basic and diluted EPS for the years ended October 31, 2023, 2022 and 2021 was as follows (amounts in thousands, except share and per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended October 31, ​ ​ 2023 ​ ​ 2022 2021 Numerator ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss attributable to FuelCell Energy, Inc. ​ $ (107,568) ​ $ (142,722) ​ $ (101,055) ​ Series B preferred stock dividends ​ ​ (3,200) ​ ​ (3,200) ​ ​ (3,200) ​ Net loss attributable to common stockholders ​ $ (110,768) ​ $ (145,922) ​ $ (104,255) ​ Denominator ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average common shares outstanding – basic ​ ​ 419,747,796 ​ ​ 383,139,140 ​ ​ 334,742,346 ​ Effect of dilutive securities (1) ​ ​ — ​ ​ — ​ ​ — ​ Weighted average common shares outstanding – diluted ​ ​ 419,747,796 ​ ​ 383,139,140 ​ ​ 334,742,346 ​ Net loss to common stockholders per share – basic ​ $ (0.26) ​ $ (0.38) ​ $ (0.31) ​ Net loss to common stockholders per share – diluted (1) ​ $ (0.26) ​ $ (0.38) ​ $ (0.31) ​ (1) Due to the net loss to common stockholders in each of the years presented above, diluted earnings per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive. As of October 31, 2023, 2022 and 2021, potentially dilutive securities excluded from the diluted loss per share calculation are as follows:
Schedule of Potentially Dilutive Securities Excluded from the Diluted Loss Per Share Calculation	As of October 31, 2023, 2022 and 2021, potentially dilutive securities excluded from the diluted loss per share calculation are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ October 31, ​ 2023 2022 ​ 2021 May 2017 Offering – Series C Warrants ​ ​ - ​ ​ - ​ ​ 950,102 Outstanding options to purchase common stock ​ ​ 18,291 ​ ​ 20,231 ​ ​ 22,388 Unvested Restricted Stock Units ​ ​ 6,543,138 ​ ​ 2,520,881 ​ ​ 2,543,541 5% Series B Cumulative Convertible Perpetual Preferred Stock ​ ​ 37,837 ​ ​ 37,837 ​ ​ 37,837 Total potentially dilutive securities ​ ​ 6,599,266 ​ ​ 2,578,949 ​ ​ 3,553,868 ​

Restricted Cash (Tables)

Restricted Cash (Tables)	12 Months Ended
	Oct. 31, 2023
Restricted Cash
Summary of Allocation of Restricted Cash	The allocation of restricted cash is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ October 31, ​ 2023 2022 Cash Restricted for Outstanding Letters of Credit (1) ​ $ 14,152 ​ $ 4,993 Cash Restricted for PNC Sale-Leaseback Transactions ​ ​ — ​ ​ 5,010 Cash Restricted for Crestmark Sale-Leaseback Transactions ​ ​ 2,901 ​ ​ 2,894 Bridgeport Fuel Cell Park Project Debt Service and Performance Reserves ​ ​ — ​ ​ 8,746 Debt Service and Performance Reserves related to OpCo Financing Facility ​ ​ 19,698 ​ ​ — Debt Service and Performance Reserves related to the Senior and Subordinated Back Leverage Loan Facilities ​ ​ 9,294 ​ ​ — Other ​ ​ 3,579 ​ ​ 1,346 Total Restricted Cash ​ ​ 49,624 ​ ​ 22,989 Restricted Cash and Cash Equivalents – Short-Term (2) ​ ​ (5,159) ​ ​ (4,423) Restricted Cash and Cash Equivalents – Long-Term ​ $ 44,465 ​ $ 18,566 (1) Letters of credit outstanding as of October 31, 2023 expire on various dates through August 2028. (2) Short-term restricted cash and cash equivalents are amounts expected to be released and categorized as unrestricted cash within twelve months of the balance sheet date.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Oct. 31, 2023
Supplemental Cash Flow Information
Schedule of Cash Flow, Supplemental Disclosures	The following represents supplemental cash flow information (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended October 31, ​ 2023 2022 2021 Cash interest paid ​ $ 3,088 ​ $ 1,556 ​ $ 5,765 Income taxes paid ​ 6 ​ 2 ​ 6 Noncash financing and investing activity: ​ ​ ​ ​ ​ ​ Noncash reclassifications between inventory and project assets ​ 1,987 ​ 1,260 ​ 7,052 Noncash reclassifications from inventory to fixed assets ​ ​ — ​ ​ 1,552 ​ ​ — Noncash reclassifications from other assets to project assets ​ ​ — ​ ​ 2,375 ​ ​ — Director stock compensation ​ 225 ​ 305 ​ 275 Accrued noncontrolling interest distribution ​ ​ 148 ​ ​ — ​ ​ — Addition of operating lease liabilities ​ 1,952 ​ — ​ 1,459 Addition of operating lease right-of-use assets ​ 1,952 ​ — ​ 1,459 Reclassification to equity of warrant liability for warrant exercises ​ — ​ — ​ 21,170 Noncash reduction in basis of project assets ​ ​ 6,330 ​ ​ — ​ ​ — Accrued purchase of fixed assets, cash paid to be paid in subsequent period ​ 1,646 ​ 4,396 ​ 1,537 Accrued purchase of project assets, cash to be paid in subsequent period ​ 4,515 ​ 6,444 ​ 6,707 ​

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands						1 Months Ended	3 Months Ended	11 Months Ended	12 Months Ended			16 Months Ended
	Oct. 31, 2023 USD ($) loanfacility shares	Jul. 12, 2023 shares	May 19, 2023 USD ($)	Aug. 04, 2021 USD ($)	Jun. 11, 2021 USD ($)	Aug. 31, 2021 USD ($) MW	Oct. 31, 2023 USD ($) loanfacility Plant MW shares	Apr. 30, 2022 USD ($) $ / shares shares	Oct. 31, 2023 USD ($) loanfacility Plant $ / shares MW shares	Oct. 31, 2022 USD ($) $ / shares shares	Oct. 31, 2021 USD ($) shares	Oct. 31, 2023 USD ($) loanfacility $ / shares shares	Jul. 07, 2022 USD ($)
Nature of Business and Basis of Presentation
Cash and cash equivalents, unrestricted	$ 249,952						$ 249,952		$ 249,952	$ 458,055		$ 249,952
Investments - short-term	$ 103,760						$ 103,760		103,760			$ 103,760
Proceeds from the issuance of debt									$ 100,500		$ 10,175
Number of Term Loan Facilities | loanfacility	2						2		2			2
Allowance for doubtful accounts or credit losses	$ 0						$ 0		$ 0	0		$ 0
Impairment of goodwill									$ 0	0	0
Percentage of electricity output provided to customers									100%
Extended Product Warranty Description									We warranty our products for a specific period of time against manufacturing or performance defects. Our U.S. warranty is generally limited to a term of 15 months after shipment or 12 months after acceptance of our products.
Extended product warranty period after shipment									15 months
Extended product warranty period after acceptance of products									12 months
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax									$ (400)	(900)	$ (900)
Senior Back Leverage Loan Facility
Nature of Business and Basis of Presentation
Gross proceeds from debt							20,000
Maximum
Nature of Business and Basis of Presentation
Operating and finance lease, remaining lease term									26 years
Minimum
Nature of Business and Basis of Presentation
Operating and finance lease, remaining lease term									1 year
US Treasury Securities
Nature of Business and Basis of Presentation
Investments - short-term	103,800						103,800		$ 103,800	$ 0		103,800
OpCo Financing Facility
Nature of Business and Basis of Presentation
Proceeds from the issuance of debt			$ 77,600						80,500
Net proceeds from issuance debt									46,100
Unrestricted cash			46,100
Funds Released from Restricted Cash			$ 11,200
East West Bank Partnership Flip Transaction
Nature of Business and Basis of Presentation
Capacity Of Plant | MW						7.4
Closing costs				$ 800
Tax Equity Financing Commitment						$ 15,000							$ 12,000
Remaining amount of draw				$ 12,000
Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Closing costs							$ 1,800		$ 1,800
Number of Fuel Cell Power Plants, Tax Equity Financing Transaction | Plant							2		2
Tax Equity Financing Commitment	30,200						$ 30,200		$ 30,200			$ 30,200
Tax equity financing transaction, commitment amount received	$ 9,100								$ 9,100
Common Stock
Nature of Business and Basis of Presentation
Stock issued during period shares new issues | shares									44,320,825	38,396,904	69,074,573
Common Stock | 2022 Open Market Sale Agreement | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC
Nature of Business and Basis of Presentation
Shares sold during the period | shares									44,300,000			62,800,000
Average sale price per share | $ / shares									$ 2.25			$ 2.66
Gross proceeds from issuance of common stock									$ 99,700			$ 166,800
Shares remaining under the plan | shares	32,200,000						32,200,000		32,200,000			32,200,000
Common Stock | 2022 Open Market Sale Agreement | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC | Maximum
Nature of Business and Basis of Presentation
Stock issued during period shares new issues | shares		95,000,000
Common Stock | 2021 Open Market Sale Agreement | Jefferies LLC and Barclays Capital Inc.
Nature of Business and Basis of Presentation
Aggregate offering price					$ 500,000
Average sale price per share | $ / shares								$ 7.79		$ 6.07
Stock issued during period shares new issues | shares								64,000,000		19,900,000
Gross proceeds from issuance of common stock								$ 498,100		$ 120,800
Derby Project
Nature of Business and Basis of Presentation
Proceeds from License Fees Received							$ 500
Derby Project | Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Percentage of Cash and Tax Allocations to be Received									95%
Remaining amount of draw	$ 20,600						$ 20,600		$ 20,600			$ 20,600
Derby Project 14.0 Mega Watt | Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Capacity Of Plant | MW							14		14
Derby Project 2.8 Mega Watt | Tax equity financing transactions with Franklin Park
Nature of Business and Basis of Presentation
Capacity Of Plant | MW							2.8		2.8
Variable interest entity ("VIE")
Nature of Business and Basis of Presentation
Cash and cash equivalents, unrestricted	$ 4,797						$ 4,797		$ 4,797	$ 2,149		$ 4,797

Nature of Business, Basis of _3

Nature of Business, Basis of Presentation and Significant Accounting Policies - Percent of Customer Consolidated Revenues (Details) - Sales Revenue Net Member - Customer Concentration Risk Member	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Korea Southern Power Company [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Significant customer revenue percentage	31%	6%	12%
Korea Fuel Cell Co. Limited [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Significant customer revenue percentage	16%	46%
Connecticut Light And Power. [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Significant customer revenue percentage	13%	14%	20%
ExxonMobil Technology and Engineering Company [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Significant customer revenue percentage	8%	8%	29%
Top Customers [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Significant customer revenue percentage	68%	74%	61%

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Details)			1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 20, 2021 USD ($) item	Oct. 29, 2021 USD ($)	May 31, 2023 USD ($)	Apr. 30, 2022 USD ($)	Oct. 31, 2023 USD ($)	Oct. 31, 2022 USD ($) item	Oct. 31, 2021 USD ($)	Oct. 31, 2019 USD ($)	Aug. 25, 2023 USD ($)	Aug. 24, 2023 USD ($)	Jul. 31, 2023 item	Dec. 31, 2022 item	Dec. 19, 2022 USD ($)	Dec. 18, 2022 USD ($)	Apr. 29, 2022 USD ($)	Apr. 28, 2022 USD ($)
Disaggregation Of Revenue [Line Items]
Percentage of electricity output provided to customers					100%
Contract asset					$ 42,100,000	$ 20,700,000
Long-term					25,800,000	9,700,000
Contract liability					3,100,000	25,400,000
Consideration payable					6,300,000
Long term					6,000,000
Sale of investment tax credit					6,300,000
Transferred to accounts receivable					12,900,000	5,300,000
Revenues					123,394,000	130,484,000	$ 69,585,000
Research and development expenses					61,021,000	34,529,000	11,315,000
POSCO Energy Settlement Agreement
Disaggregation Of Revenue [Line Items]
Number of modules | item	2
Stand alone selling price per sale module	$ 3,000,000
Extended warranty term	7 years
Stand alone selling price per warranty module	$ 650,000
Settlement agreement variable consideration from contract with customer						$ 13,100,000
Number of additional modules expired without exercised | item												14
Option to purchase warranty module units | item						20
Settlement agreement number of module units sold | item	20					20
Option to purchase additional warranty module units | item	14
Modules units, order placed | item	20
Revenues					9,100,000
Emre joint development agreement
Disaggregation Of Revenue [Line Items]
Revenues			$ 2,500,000		300,000
Research costs reimbursement amount									$ 67,000,000	$ 60,000,000			$ 60,000,000	$ 50,000,000	$ 50,000,000	$ 45,000,000
Research and development expenses								$ 45,000,000
Milestone payment received						$ 5,000,000
Milestone based payments				$ 5,000,000
Investment Amount		$ 5,000,000
Emre joint development agreement | Rotterdam Project
Disaggregation Of Revenue [Line Items]
Investment amount						5,000,000
Remaining balance						2,500,000
Investment Amount						5,000,000
Product
Disaggregation Of Revenue [Line Items]
Revenues					19,589,000	60,000,000
Remaining performance obligations					0
Service and License
Disaggregation Of Revenue [Line Items]
Revenues					49,084,000	12,786,000	19,791,000
Remaining performance obligations					140,800,000
Generation
Disaggregation Of Revenue [Line Items]
Revenues					37,508,000	36,186,000	24,027,000
Remaining performance obligations					63,900,000
Advanced Technologies
Disaggregation Of Revenue [Line Items]
Revenues					17,213,000	$ 21,512,000	$ 25,767,000
Remaining performance obligations					15,300,000
KFC/Posco International Company (PE Group)
Disaggregation Of Revenue [Line Items]
Amount Recognized Under The Settlement Agreement					13,100,000
Revenues					$ 10,500,000
KFC/Posco International Company (PE Group) | LTSA | Noeul
Disaggregation Of Revenue [Line Items]
Number of modules transfer | item											16
Posco Energy | LTSA | Noeul
Disaggregation Of Revenue [Line Items]
Number of modules transfer | item											16

Tax Equity Financings and Inv_2

Tax Equity Financings and Investment Tax Credit Sale (Details)										1 Months Ended		3 Months Ended		12 Months Ended
	Oct. 31, 2023 USD ($)	Dec. 16, 2022 USD ($) MW	Dec. 15, 2022 MW	Oct. 04, 2022 MW	Jul. 07, 2022 USD ($)	May 15, 2022 USD ($)	Dec. 13, 2021 USD ($)	Oct. 18, 2021	Aug. 04, 2021 USD ($)	Nov. 30, 2021 USD ($) MW	Aug. 31, 2021 USD ($) MW	Oct. 31, 2023 USD ($) Plant MW	Apr. 30, 2022 USD ($)	Oct. 31, 2023 USD ($) Plant MW	Oct. 31, 2022 USD ($)	Oct. 31, 2021 USD ($)	Jan. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Tax Equity Financing
Net (loss) income attributable to noncontrolling interest														$ (488,000)	$ (4,510,000)	$ 30,000
Accrued performance obligation	$ 3,958,000											$ 3,958,000		3,958,000
Groton Project [Member]
Tax Equity Financing
Capacity of plant | MW		6	7.4
Payment of amendment fee		$ 1,200,000
Net (loss) income attributable to noncontrolling interest														$ (2,500,000)	0
Percentage of cash and tax allocations to be received														95%
East West Bank Partnership Flip Transaction
Tax Equity Financing
Capacity of plant | MW											7.4
Tax equity financing commitment					$ 12,000,000						$ 15,000,000
Tax equity financing, Aggregate fee					500,000
Tax equity financing, Withdrawal right, Percent of return of investment								101%
Initial draw									$ 3,000,000
Closing costs									800,000
Remaining amount of draw									$ 12,000,000
Fee for extension of commercial operation deadline						$ 400,000
Net (loss) income attributable to noncontrolling interest																$ (30,000)
Percentage reflecting conditional withdrawal for loss attributable to non controlling interest																1%
East West Bank Partnership Flip Transaction | Groton Project [Member]
Tax Equity Financing
Tax equity financing, Aggregate fee		$ 500,000
REI Partnership Flip Transaction
Tax Equity Financing
Capacity of plant | MW										7.4
Tax equity financing commitment										$ 12,400,000			$ 11,900,000
Amount of Refund													$ 500,000
Amount of distribution															$ 300,000
Percentage of annual interest rate															2.73%
Initial draw							$ 3,200,000
Closing costs							$ 400,000
Remaining amount of draw																	$ 9,200,000	$ 9,200,000
Legal and advisory fees															$ 400,000
Net (loss) income attributable to noncontrolling interest														$ 2,000,000	$ (4,500,000)
Percentage of cash and tax allocations to be received										95%
Percentage of amount payable										10.30%
Tax equity financing transactions with Franklin Park
Tax Equity Financing
Number of Fuel Cell Power Plants, Tax Equity Financing Transaction | Plant												2		2
Tax equity financing commitment	30,200,000											$ 30,200,000		$ 30,200,000
Tax equity financing transaction, commitment amount received	9,100,000													9,100,000
Closing costs												1,800,000		1,800,000
Tax equity financing transactions with Franklin Park | Derby Project
Tax Equity Financing
Estimated additional fees														500,000
Additional funding														20,600,000
Remaining amount of draw	20,600,000											$ 20,600,000		$ 20,600,000
Percentage of cash and tax allocations to be received														95%
Tax equity financing transactions with Franklin Park | Derby Project 14.0 Mega Watt
Tax Equity Financing
Capacity of plant | MW												14		14
Tax equity financing transactions with Franklin Park | Derby Project 2.8 Mega Watt
Tax Equity Financing
Capacity of plant | MW												2.8		2.8
Toyota Investment Tax Credit Sale | REI
Tax Equity Financing
Project's qualified ITCs	8,400,000
Purchase amount of ITCs	7,100,000
Eligible capital expenditure ITC rate per $1 purchased ITCs	0.85
Transaction costs	400,000
Accrued performance obligation	$ 6,300,000											$ 6,300,000		$ 6,300,000
First Anniversary of Project Achieving Commercial Operations [Member] | East West Bank Partnership Flip Transaction
Tax Equity Financing
Tax equity financing commitment, Contributions					4,000,000
Second Anniversary of Project Achieving Commercial Operations [Member] | East West Bank Partnership Flip Transaction
Tax Equity Financing
Tax equity financing commitment, Contributions					4,000,000
Third Anniversary of Project Achieving Commercial Operations [Member] | East West Bank Partnership Flip Transaction
Tax Equity Financing
Tax equity financing commitment, Contributions					$ 4,000,000
Maximum | East West Bank Partnership Flip Transaction | Groton Project [Member]
Tax Equity Financing
Capacity of plant | MW				7.4

Investments - Short-Term (Detai

Investments - Short-Term (Details) - U.S. Treasury Securities $ in Thousands	Oct. 31, 2023 USD ($)
Investments in United States Treasury Securities
Amortized cost	$ 103,760
Gross unrealized gains	1
Fair value	$ 103,761
Weighted average yield to maturity	5.45%

Inventories - Components of Inv

Inventories - Components of Inventories (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Inventories
Raw materials	$ 36,200	$ 30,624
Work-in-process	55,585	67,834
Inventories	91,785	98,458
Inventories - current	(84,456)	(90,909)
Inventories - long-term	$ 7,329	$ 7,549

Project Assets - Summary of Pro

Project Assets - Summary of Project Assets (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Project Assets [Line Items]
Accumulated depreciation	$ (46,263)	$ (29,546)
Project Assets, net	258,066	232,886
Project Assets - Operating
Project Assets [Line Items]
Project Assets, gross	213,753	154,736
Project Assets - Operating, net	$ 167,490	125,190
Project Assets - Operating | Minimum
Project Assets [Line Items]
Project assets estimated useful life	4 years
Project Assets - Operating | Maximum
Project Assets [Line Items]
Project assets estimated useful life	20 years
Project Assets - Construction in progress
Project Assets [Line Items]
Project Assets, gross	$ 90,576	$ 107,696
Project Assets - Construction in progress | Minimum
Project Assets [Line Items]
Project assets estimated useful life	7 years
Project Assets - Construction in progress | Maximum
Project Assets [Line Items]
Project assets estimated useful life	20 years
Project Assets BOP And Site Construction
Project Assets [Line Items]
Project assets estimated useful life	20 years
Project Assets Modules | Minimum
Project Assets [Line Items]
Project assets estimated useful life	4 years
Project Assets Modules | Maximum
Project Assets [Line Items]
Project assets estimated useful life	7 years

Project Assets - Additional Inf

Project Assets - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2018 project MW	Jul. 31, 2017 project MW	Oct. 31, 2022 USD ($) MW	Oct. 31, 2021 USD ($)	Oct. 31, 2023 USD ($) project item MW	Oct. 31, 2022 USD ($) item	Oct. 31, 2021 USD ($)
Project Assets [Line Items]
Number of project assets | item					9	8
Impairment charges					$ 2,400
Long Term Project Assets			$ 232,886		$ 258,066	$ 232,886
Total number of projects | project					3
Sale leaseback transaction, net book value			125,200		$ 167,500	125,200
Long-term project assets construction in progress			107,700		90,600	107,700
Project asset depreciation					19,000	14,200	$ 13,700
Hartford
Project Assets [Line Items]
Impairment charges			$ 800
Power Purchase Agreement | NEW YORK
Project Assets [Line Items]
Total Power to be purchased | MW		39.8
Number of projects executed | project	1
Impairment charges				$ 1,800
Total number of projects | project	3	3
Power purchased | MW	7.4
Number of projects not executed | project	2
Triangle Street Project
Project Assets [Line Items]
Impairment charges				400
Long Term Project Assets				5,600			$ 5,600
Toyota Project
Project Assets [Line Items]
Amount of charges for the difference between carrying value of the project asset less the carrying value of inventory components						$ 22,100
Non-recoverable costs charged off as cost of revenue					$ 22,900
Impairment charges				$ 2,800
Power capacity under construction phase | MW					2.3
CT RFP-1, Hartford, CT | Hartford
Project Assets [Line Items]
Capacity Of Plant | MW			7.4
SCEF - Hartford, CT | Hartford
Project Assets [Line Items]
Capacity Of Plant | MW			1

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 197,669	$ 161,234
Accumulated depreciation	(108,001)	(103,097)
Property, plant and equipment, net	89,668	58,137
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	524	524
Building and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 21,430	21,216
Building and Improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Building and Improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	26 years
Machinery, Equipment and Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 136,554	108,656
Machinery, Equipment and Software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Machinery, Equipment and Software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	8 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 5,211	4,354
Estimated Useful Life	10 years
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 33,950	$ 26,484

Property, Plant and Equipment -

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Property, Plant and Equipment.
impairment charge	$ 0	$ 1,000	$ 0
Depreciation expense	$ 5,100	$ 5,800	$ 4,900

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Goodwill And Intangible Assets [Line Items]
Goodwill	$ 4,075	$ 4,075
Intangible assets, net	16,076	17,373
Amortization expenses	1,300
Impairment of goodwill	0	0	$ 0
Versa & Bridgeport Fuel Cell Project Acquisitions
Goodwill And Intangible Assets [Line Items]
Intangible assets, net	16,100	17,400
Versa Acquisition
Goodwill And Intangible Assets [Line Items]
Goodwill	4,100	4,100
Bridgeport Fuel Cell, LLC
Goodwill And Intangible Assets [Line Items]
Amortization expenses	$ 1,300	$ 1,300	$ 1,300

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Finite Lived Intangible Assets [Line Items]
Gross Amount	$ 21,912	$ 21,912
Accumulated Amortization	(5,836)	(4,539)
Net Amount	16,076	17,373
Bridgeport PPA
Finite Lived Intangible Assets [Line Items]
Gross Amount	12,320	12,320
Accumulated Amortization	(5,836)	(4,539)
Net Amount	6,484	7,781
In Process Research And Development
Finite Lived Intangible Assets [Line Items]
Gross Amount	9,592	9,592
Net Amount	$ 9,592	$ 9,592

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Accrued Liabilities
Accrued payroll and employee benefits	$ 7,752	$ 8,534
Consideration payable to a customer	3,958
Accrued service agreement and PPA costs	10,742	11,340
Accrued legal, taxes, professional and other	3,861	7,541
Accrued liabilities	$ 26,313	$ 27,415

Accrued Liabilities - Schedul_2

Accrued Liabilities - Schedule of Accrued Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	Oct. 31, 2023	Oct. 31, 2022
Accrued Liabilities
loss accruals on service contracts	$ 9.5	$ 7.3
accruals for performance guarantees	$ 1.2	$ 4.1

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Lessee Lease Description [Line Items]
Operating lease right-of-use assets, net	$ 8,352	$ 7,189
Operating lease liability	9,591
Operating lease expense	$ 1,486	1,521	$ 1,545
Operating lease, weighted average remaining lease term	17 years
Operating lease, weighted average discount rate	7%
Operating lease, payments	$ 1,226	$ 1,438	$ 1,226

Leases - Summary of Undiscounte

Leases - Summary of Undiscounted Maturities of Operating Lease and Finance Lease Liabilities (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Operating Leases
Due Year 1	$ 1,052
Due Year 2	1,276
Due Year 3	1,262
Due Year 4	1,292
Due Year 5	1,267
Thereafter	12,718
Total undiscounted lease payments	18,867
Less imputed interest	(9,276)
Total discounted lease payments	9,591
Finance Leases
Due Year 1	16
Total undiscounted lease payments	16
Less imputed interest	(4)
Total discounted lease payments	$ 12	$ 57
Finance Lease Liability Statement Of Financial Position Extensible List	Other Liabilities Noncurrent	Other Liabilities Noncurrent

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Debt Instrument [Line Items]
Finance lease obligations	$ 12	$ 57
Finance Lease Liability Statement Of Financial Position Extensible List	Other Liabilities Noncurrent	Other Liabilities Noncurrent
Deferred finance costs	$ (3,526)	$ (1,152)
Total debt and finance obligations	119,467	82,375
Current portion of long-term debt and finance obligations	(10,067)	(13,198)
Long-term debt and finance obligations	109,400	69,177
Connecticut Green Bank Loan
Debt Instrument [Line Items]
Long-term Line of Credit		4,800
Connecticut Green Bank Loan (Bridgeport Fuel Cell Project)
Debt Instrument [Line Items]
Long-term Line of Credit		3,507
Liberty Bank Term Loan Agreement (Bridgeport Fuel Cell Project)
Debt Instrument [Line Items]
Long-term Line of Credit		5,382
Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project)
Debt Instrument [Line Items]
Long-term Line of Credit		5,382
Connecticut Green Bank Loan (Senior Back-Leverage Financing)
Debt Instrument [Line Items]
Long-term Line of Credit	8,000
Liberty Bank Loan (Senior Back-Leverage Financing)
Debt Instrument [Line Items]
Long-term Line of Credit	5,876
Amalgamated Bank Loan (Senior Back-Leverage Financing)
Debt Instrument [Line Items]
Long-term Line of Credit	5,873
Finance obligation for sale-leaseback transactions
Debt Instrument [Line Items]
Long-term Line of Credit	18,814	56,625
State of Connecticut Loan
Debt Instrument [Line Items]
Long-term Line of Credit	6,908	$ 7,774
OpCo Financing Facility
Debt Instrument [Line Items]
Long-term Line of Credit	$ 77,510

Debt - Aggregate Annual Princip

Debt - Aggregate Annual Principal Payments under Loan Agreements and Finance Lease Obligations (Details) $ in Thousands	Oct. 31, 2023 USD ($)
Debt
Year 1	$ 10,712
Year 2	12,534
Year 3	12,475
Year 4	8,487
Year 5	9,858
Thereafter	59,858	[1]
Debt and Finance Leases, Future Minimum Payments Due	$ 113,924
[1] The annual principal payments included above only include sale-leaseback payments whereas the difference between debt outstanding as of October 31, 2023 and the annual principal payments represent accreted interest and amounts included in the finance obligation that exceed required principal payments.

Debt - OpCo Financing Facility

Debt - OpCo Financing Facility (Details)		12 Months Ended
	May 19, 2023 USD ($) project	Oct. 31, 2023 USD ($)	Oct. 31, 2021 USD ($)	May 22, 2023
Debt Instrument [Line Items]
Number of leased projects ownership reacquired | project	3
Payments of debt issuance costs		$ 3,469,000	$ 363,000
Proceeds from the issuance of debt		100,500,000	$ 10,175,000
Bridgeport Fuel Cell Project
Debt Instrument [Line Items]
Encumbrance amount	$ 11,400,000
Bridgeport Fuel Cell Project | Liberty Bank, Fifth Third Bank and Connecticut Green Bank
Debt Instrument [Line Items]
Repayments of debt	11,400,000
Pfizer Project
Debt Instrument [Line Items]
Future payments included in financing obligation for the remaining lease	15,700,000
Riverside Regional Water Quality Control Plant Project
Debt Instrument [Line Items]
Future payments included in financing obligation for the remaining lease	3,700,000
Santa Rita Jail Project
Debt Instrument [Line Items]
Future payments included in financing obligation for the remaining lease	$ 2,800,000
OpCo Financing Facility
Debt Instrument [Line Items]
Number of projects serving as security | project	6
Payments of debt issuance costs	$ 2,900,000
Funds released from restricted and unrestricted reserve account	7,300,000
Capital expenditure reserve funded out of debt	14,500,000
Funds Released from Restricted Cash	11,200,000
Proceeds from debt, distributed to company	34,900,000
Unrestricted cash	46,100,000
Capital Expenditure Reserve	$ 29,000,000
Debt Instrument, Period After Closing To Enter Hedge Transaction	30 days
Gain from fair value adjustment of debt		3,300,000
Threshold annual operating expense budget as percent of base case model, approval from lenders	115%
Annual operating expense budget approval from lenders, lending percent	50%
Trailing period for debt service coverage ratio	12 months
Debt service coverage ratio, testing frequency	6 months
Quarterly principal payment	$ 675,000
Proceeds from the issuance of debt	77,600,000	80,500,000
Long-term line of credit		77,510,000
OpCo Financing Facility | Sale-leaseback Arrangements with PNC
Debt Instrument [Line Items]
Repayments of debt	$ 15,000,000
OpCo Financing Facility | Interest Rate Swap | First four years
Debt Instrument [Line Items]
Net interest rate				6.366%
OpCo Financing Facility | Interest Rate Swap | Thereafter
Debt Instrument [Line Items]
Net interest rate				6.866%
OpCo Financing Facility | LIPA Yaphank Solid Waste Management Project
Debt Instrument [Line Items]
Extension term of gas agreement	3 years
Period to exercise option to purchase member interest in tax equity partnership	6 months
OpCo Financing Facility | Maximum
Debt Instrument [Line Items]
Notional amount of hedge	105%
OpCo Financing Facility | Minimum
Debt Instrument [Line Items]
Notional amount of hedge	75%
Debt service coverage ratio	1.20%
OpCo Financing Facility | Letter of credit
Debt Instrument [Line Items]
Term to maintain debt service coverage ratio	6 months
Line of credit facility, maximum borrowing capacity	$ 6,500,000
OpCo Financing Facility | Senior Term Loan
Debt Instrument [Line Items]
Principal amortization period	17 years
Debt instrument term	7 years
Line of credit facility, maximum borrowing capacity	$ 80,500,000
Debt service coverage ratio	1.30%
Debt instrument, face amount	$ 80,500,000
OpCo Financing Facility | Senior Term Loan | Applicable interest period one
Debt Instrument [Line Items]
Interest period	1 month
OpCo Financing Facility | Senior Term Loan | Applicable interest period two
Debt Instrument [Line Items]
Interest period	3 months
OpCo Financing Facility | Senior Term Loan | Applicable interest period three
Debt Instrument [Line Items]
Interest period	6 months
OpCo Financing Facility | Senior Term Loan | SOFR rate
Debt Instrument [Line Items]
Initial interest period	3 months
OpCo Financing Facility | Senior Term Loan | SOFR rate | First four years
Debt Instrument [Line Items]
Interest rate, basis points	2.50%
OpCo Financing Facility | Senior Term Loan | SOFR rate | Thereafter
Debt Instrument [Line Items]
Interest rate, basis points	3%
OpCo Financing Facility | Senior Term Loan | Base rate | First four years
Debt Instrument [Line Items]
Interest rate, basis points	1.50%
OpCo Financing Facility | Senior Term Loan | Base rate | Thereafter
Debt Instrument [Line Items]
Interest rate, basis points	2%
OpCo Financing Facility | Senior Term Loan | Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of hedge				100%
Interest rate				3.716%
Connecticut Green Bank Notes
Debt Instrument [Line Items]
Repayments of debt	$ 1,800,000	$ 1,800,000
PNC Energy Capital, LLC
Debt Instrument [Line Items]
Repayments of debt	$ 7,300,000

Debt - Back Leverage Financing

Debt - Back Leverage Financing (Details) - USD ($) $ in Thousands		3 Months Ended
	Aug. 18, 2023	Oct. 31, 2023
Senior Back Leverage Loan Facility
Debt Instrument [Line Items]
Gross proceeds from debt		$ 20,000
Back Leverage Financing
Debt Instrument [Line Items]
Gross proceeds from debt	$ 20,000
Payments of debt issuance costs	400
Net proceeds from debt	19,600
Payment to fund DSCR Reserve Accounts	1,700
Payment to fund O&M Reserve Accounts	6,500
Proceeds from debt, distributed to company	11,100
Output shortfall payments	1,300
Unrestricted cash	$ 6,800
Trailing period for debt service coverage ratio	12 months
Term to acquire interest at flip point	90 days
Back Leverage Financing | Minimum
Debt Instrument [Line Items]
Debt service coverage ratio	1.10%
Back Leverage Financing | Senior Back Leverage Loan Facility
Debt Instrument [Line Items]
Debt instrument term	10 years
Basis points	2.75
Excess cashflow available to borrower (as a percent)	50%
Term following commercial operations date and termination of the Amended and Restated PPA	20 years
Term of interest only period	84 months
Back Leverage Financing | Senior Back Leverage Loan Facility | Step Down Date
Debt Instrument [Line Items]
Interest rate (as a percent)	8%
Back Leverage Financing | Senior Back Leverage Loan Facility | After the Step Down Date
Debt Instrument [Line Items]
Floor rate (as a percent)	5%
Back Leverage Financing | Senior Back Leverage Loan Facility | Prepayment on or prior to the second anniversary
Debt Instrument [Line Items]
Prepayment fee (as percentage)	3%
Back Leverage Financing | Senior Back Leverage Loan Facility | Prepayment after second anniversary of the closing date but on or prior to the fourth anniversary
Debt Instrument [Line Items]
Prepayment fee (as percentage)	2%
Back Leverage Financing | Senior Back Leverage Loan Facility | Prepayment after fourth anniversary of the closing date but on or prior to the seventh anniversary
Debt Instrument [Line Items]
Prepayment fee (as percentage)	1%
Back Leverage Financing | Senior Back Leverage Loan Facility | Minimum
Debt Instrument [Line Items]
Debt service coverage ratio	1.20%
Back Leverage Financing | Senior Back Leverage Loan Facility | Maximum | After the Step Down Date
Debt Instrument [Line Items]
Interest rate (as a percent)	8%
Back Leverage Financing | Subordinated Back Leverage Loan Facility
Debt Instrument [Line Items]
Debt instrument term	7 years
Back Leverage Financing | Liberty Lender
Debt Instrument [Line Items]
Payment to fund DSCR Reserve Accounts	$ 830
Payment to fund O&M Reserve Accounts	$ 3,250
Interest rate (as a percent)	6.75%
Back Leverage Financing | Liberty Lender | Term Loan Facility
Debt Instrument [Line Items]
Loan provided by lender (as a percentage)	50%
Back Leverage Financing | Amalgamated Lender
Debt Instrument [Line Items]
Payment to fund DSCR Reserve Accounts	$ 830
Payment to fund O&M Reserve Accounts	$ 3,250
Annual carbon emissions price multiplier	12.66
Back Leverage Financing | Amalgamated Lender | Carbon Offset Event Continuing
Debt Instrument [Line Items]
Interest rate (as a percent)	7.32%
Back Leverage Financing | Amalgamated Lender | Carbon Offset Event Non Continuing
Debt Instrument [Line Items]
Interest rate (as a percent)	6.07%
Back Leverage Financing | Amalgamated Lender | Term Loan Facility
Debt Instrument [Line Items]
Loan provided by lender (as a percentage)	50%
Back Leverage Financing | Senior Back Leverage Lenders
Debt Instrument [Line Items]
Payment to fund DSCR Reserve Accounts	$ 300
Back Leverage Financing | Senior Back Leverage Lenders | Term Loan Facility
Debt Instrument [Line Items]
Term loan facility	12,000
Back Leverage Financing | Subordinated Back Leverage Lenders | Term Loan Facility
Debt Instrument [Line Items]
Term loan facility	$ 8,000

Debt - Other Instruments (Detai

Debt - Other Instruments (Details)

1 Months Ended

12 Months Ended

Aug. 18, 2023 USD ($)

May 19, 2023 USD ($) MW

Dec. 07, 2020 USD ($)

Nov. 30, 2020 USD ($)

Apr. 30, 2023 USD ($) position

Jan. 31, 2019 USD ($) position

Nov. 30, 2015 USD ($)

Oct. 31, 2015 USD ($) position

Oct. 31, 2023 USD ($)

Oct. 31, 2022 USD ($)

Oct. 31, 2021 USD ($)

Oct. 31, 2020 USD ($)

Debt Instrument [Line Items]

Repayments of long term debt

$ 47,830,000

$ 9,544,000

$ 98,642,000

Orion Energy Partners Investment Agent, LLC Credit Facility

Debt Instrument [Line Items]

Repayments Of Debt

$ 87,300,000

Debt instrument prepayment premium

4,000,000

$ 14,900,000

Remaining deferred finance expense

7,100,000

Orion Energy Partners Investment Agent, LLC Credit Facility | Senior Secured Credit Facility

Debt Instrument [Line Items]

Long-term line of credit

$ 200,000,000

Orion Energy Partners Investment Agent, LLC Credit Facility | Maximum

Debt Instrument [Line Items]

Debt instrument prepayment premium

$ 4,000,000

Connecticut Green Bank Loan (Bridgeport Fuel Cell Project)

Debt Instrument [Line Items]

Long-term line of credit

3,507,000

Connecticut Green Bank Loan (Bridgeport Fuel Cell Project) | Subordinated Credit Agreement

Debt Instrument [Line Items]

Repayment of long term loan

$ 3,500,000

Liberty Bank Term Loan Agreement (Bridgeport Fuel Cell Project)

Debt Instrument [Line Items]

Long-term line of credit

5,382,000

Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project)

Debt Instrument [Line Items]

Long-term line of credit

5,382,000

Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project) | Senior credit agreement

Debt Instrument [Line Items]

Repayment of long term loan

$ 8,400,000

Fifth Third Bank Term Loan Agreement (Bridgeport Fuel Cell Project) | Senior credit agreement | Bridgeport Fuel Cell, LLC

Debt Instrument [Line Items]

Capacity Of Plant | MW

14.9

Connecticut Green Bank Loan

Debt Instrument [Line Items]

Repayments of long term debt

4,800,000

Long-term line of credit

4,800,000

Subordinated Credit Agreement | Connecticut Green Bank Loans | Bridgeport Fuel Cell, LLC

Debt Instrument [Line Items]

Capacity Of Plant | MW

14.9

Back Leverage Financing | Liberty Lender

Debt Instrument [Line Items]

Interest rate (as a percent)

6.75%

Connecticut Green Bank Loans

Debt Instrument [Line Items]

Repayments Of Debt

$ 3,000,000

Finance obligation for sale-leaseback transactions

Debt Instrument [Line Items]

Long-term line of credit

18,814,000

56,625,000

Finance obligations for sale leaseback agreements

Debt Instrument [Line Items]

Future payments included in financing obligation for the remaining lease

$ 9,100,000

Purchase right percentage of projected assets at fair market value

31%

Finance obligations for sale leaseback agreements | PNC Energy Capital, LLC

Debt Instrument [Line Items]

Long-term line of credit

$ 18,800,000

56,600,000

State of Connecticut Loan

Debt Instrument [Line Items]

Long-term line of credit

$ 6,908,000

$ 7,774,000

Debt instrument, face amount

$ 10,000,000

$ 10,000,000

Interest rate (as a percent)

2%

Debt instrument term

15 years

Debt instrument, payment terms, period principal payments are deferred

4 years

Debt instrument, date of first required payment

Dec. 01, 2019

Amount of loan forgiveness

$ 2,000,000

Loans Forgiveness Terms

if the Company created 165 full-time positions and retained 538 full-time positions for two consecutive years (as amended from time to time, the “Employment Obligation”) as measured on October 28, 2017 (as amended from time to time, the “Target Date”). The Assistance Agreement was subsequently amended in April 2017 to extend the Target Date by two years to October 28, 2019.

Number of full time positions required to be created | position

91

165

Number of full time positions required to be retained | position

538

538

538

Consecutive term for average number of employees

24 months

24 months

2 years

Principal payable number of employee under employee obligation target

$ 14,225

Number of minimum full time positions required to be maintained | position

91

Number of minimum full time positions required to be maintained including additional employment positions | position

629

Additional credits to be earned

$ 2,000,000

Debt Instrument, Period After Employment Period For Submission Of Job Audit

90 days

State of Connecticut Loan | Maximum

Debt Instrument [Line Items]

Amount of loan forgiveness

$ 5,000,000

Stockholders' Equity and Warr_2

Stockholders' Equity and Warrant Liabilities - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands									11 Months Ended	12 Months Ended			16 Months Ended
	Jul. 12, 2023	Jul. 12, 2022	Jun. 11, 2021	Dec. 07, 2020	Dec. 04, 2020	Nov. 22, 2019	Oct. 31, 2019	May 03, 2017	Apr. 30, 2022	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2023	Oct. 11, 2023	Oct. 10, 2023	Apr. 08, 2021	Apr. 07, 2021
Stockholders' Equity Note
Number of incremental common stock shares approved															500,000,000	162,500,000
Common stock, shares authorized										1,000,000,000	500,000,000		1,000,000,000	1,000,000,000	500,000,000	500,000,000	337,500,000
Drew down to fully repay debt outstanding										$ 100,500		$ 10,175
Class of warrants or rights charge												$ 16,000
Reclassification of estimated fair value of warrant liability to additional paid in capital				$ 21,200
Common Stock
Stockholders' Equity Note
Stock issued during period shares new issues										44,320,825	38,396,904	69,074,573
Common Stock | Series C Warrants
Stockholders' Equity Note
Stock issued during period shares new issues											0	14,026
Net proceeds from common stock and warrants												$ 300
Orion Energy Partners Investment Agent, LLC Credit Facility | Exercise Price 0.242
Stockholders' Equity Note
Exercise price of warrants or rights				$ 0.242
Class of warrants or rights purchase				2,700,000
Class of warrants or rights issued value				$ 600
Orion Credit Agreement | Initial Funding Warrants
Stockholders' Equity Note
Class of warrants or rights issued							6,000,000
Exercise price of warrants or rights							$ 0.310
Orion Credit Agreement | Second Funding Warrants
Stockholders' Equity Note
Class of warrants or rights issued						14,000,000
Orion Credit Agreement | Second Funding Warrants | Exercise Price 0.242
Stockholders' Equity Note
Class of warrants or rights issued						8,000,000
Exercise price of warrants or rights						$ 0.242
Orion Credit Agreement | Second Funding Warrants | Exercise Price 0.620
Stockholders' Equity Note
Class of warrants or rights issued						6,000,000
Exercise price of warrants or rights						$ 0.620
2022 Open Market Sale Agreement | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC
Stockholders' Equity Note
Percentage of sales commission		2%
2022 Open Market Sale Agreement | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC | Common Stock
Stockholders' Equity Note
Shares sold during the period										44,300,000			62,800,000
Gross proceeds from issuance of common stock										$ 99,700			$ 166,800
Gross proceeds from sale of common stock										97,400			162,700
Payments of commissions										$ 2,300			$ 4,100
Average sale price per share										$ 2.25			$ 2.66
Shares remaining under the plan										32,200,000			32,200,000
2022 Open Market Sale Agreement | Maximum | Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC | Common Stock
Stockholders' Equity Note
Stock issued during period shares new issues	95,000,000
2021 Open Market Sale Agreement | Jefferies LLC and Barclays Capital Inc. | Common Stock
Stockholders' Equity Note
Stock issued during period shares new issues									64,000,000		19,900,000
Gross proceeds from issuance of common stock									$ 498,100		$ 120,800
Gross proceeds from sale of common stock									488,100		2,400
Payments of commissions									$ 10,000		$ 118,300
Aggregate offering price			$ 500,000
Percentage of sales commission			2%
Average sale price per share									$ 7.79		$ 6.07
Underwriting Agreement
Stockholders' Equity Note
Stock issued to underwriters					19,822,219
Sale of stock, number of shares issued in transaction					14,696,320
Sale of stock, price per share					$ 6.50
Stock issued during period shares new issues					25,000,000
Gross proceeds from sale of common stock					$ 162,500
Underwriting discounts and commissions					$ 0.2275
Net proceeds from issuance of common stock					$ 156,400
Underwriting Agreement | Maximum
Stockholders' Equity Note
Option to purchase additional common stock shares					5,177,781
Underwriting Public offering | Series C Warrants
Stockholders' Equity Note
Class of warrants or rights issued								1,000,000
Warrants issued, price per share								$ 19.20
Class of warrant or right term								5 years

Redeemable Preferred Stock (Det

Redeemable Preferred Stock (Details) - $ / shares	1 Months Ended	12 Months Ended
	Mar. 31, 2005	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Class Of Stock [Line Items]
Preferred stock, par value		$ 0.01
Maximum
Class Of Stock [Line Items]
Preferred stock, shares authorized		250,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares authorized	105,875	105,875
Preferred stock, dividend rate, percentage	5%	5%	5%	5%

Redeemable Preferred Stock - Re

Redeemable Preferred Stock - Redeemable Series B Preferred Stock (Details) - Series B Preferred Stock - USD ($) $ / shares in Units, $ in Thousands	Oct. 31, 2023	Oct. 31, 2022	Mar. 31, 2005
Class Of Stock [Line Items]
Preferred stock, shares authorized	105,875		105,875
Preferred stock, liquidation preference per share	$ 1,000
Preferred stock shares outstanding	64,020	64,020
Temporary equity, carrying amount, attributable to parent	$ 59,857	$ 59,857
Preferred stock, shares issued	64,020	64,020

Redeemable Preferred Stock - Di

Redeemable Preferred Stock - Dividends, Liquidations and Conversion Rights (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2005	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Class Of Stock [Line Items]
Dividends declared		$ 3,200,000	$ 3,200,000	$ 3,200,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividends per share, declared		$ 50
Dividends, preferred stock, cash		$ 3,200,000	3,200,000
Cumulative unpaid dividends		800,000	800,000
Dividends declared		$ 3,200,000	$ 3,200,000	$ 3,200,000
Preferred stock, dividend rate, percentage	5%	5%	5%	5%
Preferred stock, liquidation preference per share		$ 1,000
Payment on junior shares		$ 0
Preferred Stock, Liquidation Preference, Value		$ 64,020,000	$ 64,020,000
Shares of common stock issued upon conversion		0.591
Stock conversion price		$ 1,692
Percent of conversion price to exceed to exercise conversion right		150%
Number of trading days		20 days
Number of consecutive trading days		30 days

Redeemable Preferred Stock - _2

Redeemable Preferred Stock - Redemption and Voting Rights (Details) - Series B Preferred Stock	12 Months Ended
	Oct. 31, 2023
Class Of Stock [Line Items]
Percentage of voting rights	50%
Consecutive number of years	2 years
Percentage of aggregate voting power	100%
Number of trading days	20 days
Number of consecutive trading days	30 days
Percentage of conversion price	105%
Discount on market price of shares of common stock	5%
Preferred stock, voting rights	no voting rights
Minimum
Class Of Stock [Line Items]
Percentage of consideration excluding cash payments for fractional shares	90%
Common Stock
Class Of Stock [Line Items]
Number of trading days	5 days
Number of consecutive trading days	10 days

Segment Information - Additiona

Segment Information - Additional Information (Details)	12 Months Ended
	Oct. 31, 2023 item
Segment Information
Number of identified business segment	1

Segment Information - Revenues

Segment Information - Revenues by Geographic Locations (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 123,394	$ 130,484	$ 69,585
United States
Segment Reporting Information [Line Items]
Total revenues	63,289	60,290	58,393
South Korea
Segment Reporting Information [Line Items]
Total revenues	58,432	68,341	8,161
Europe
Segment Reporting Information [Line Items]
Total revenues	$ 1,673	$ 1,853	$ 3,031

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Details)						12 Months Ended
	Nov. 17, 2023	May 22, 2023 shares	Dec. 05, 2022 USD ($) item shares	Dec. 10, 2021 item USD ($)	Nov. 24, 2020 item USD ($) $ / shares	Oct. 31, 2023 USD ($) shares	Oct. 31, 2022 USD ($) shares	Oct. 31, 2021 USD ($) shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted		0
Common stock issued, non-employee compensation (in shares)						103,631	76,848	31,889
Noninterest Expense Directors Fees | $						$ 200,000	$ 200,000	$ 300,000
Employer Matching Contribution Percentage						2%
Defined Contribution Plan, Cost Recognized | $						$ 1,100,000	$ 500,000	$ 400,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock or Unit Expense | $						$ 17,000,000
Restricted Stock or Unit Expense weighted average period						2 years
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Granted, Shares						1,124,953
Time Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Granted, Shares						4,538,236
Third Amended and Restated 2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized		18,333,333
Common stock, shares available for issuance						9,069,450
Amended and Restated 2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price as percentage of offering price		85%
ESOP, period for which sale of shares is restricted		6 months
Long Term Incentive Plan Fiscal 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of award components | item					3
Common stock, shares reserved for issuance						210,190
Long Term Incentive Plan Fiscal 2021 | Relative Total Shareholder Return Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percent of Performance Payout	73.541%
Award Calibration Percentage					100%
Variance from Award Calibration Percentage					50%
Award Cap, Percent					200%
Award Additional Cap, Percent					100%
Threshold Consecutive Trading Days | $					20
Long Term Incentive Plan Fiscal 2021 | Absolute Total Shareholder Return Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award Cap, Percent					200%
Threshold Consecutive Trading Days | $					20
Share Price | $ / shares					$ 2.27
Percent of increase in stock price								150%
Percent of target award earned								200%
Long Term Incentive Plan Fiscal 2021 | Absolute Total Shareholder Return Performance Shares | Stock Price Increase 25 Percent
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percent of increase in stock price					25%
Percent of target award earned					50%
Long Term Incentive Plan Fiscal 2021 | Absolute Total Shareholder Return Performance Shares | Stock Price Increase 50 Percent
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percent of increase in stock price					50%
Percent of target award earned					100%
Long Term Incentive Plan Fiscal 2021 | Absolute Total Shareholder Return Performance Shares | Stock Price Increase 100 Percent
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percent of increase in stock price					100%
Percent of target award earned					200%
Long Term Incentive Plan Fiscal 2021 | Time Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of warrants vesting								33%
Long Term Incentive Plan Fiscal 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of award components | item				2
Common stock, shares reserved for issuance						175,548
Long Term Incentive Plan Fiscal 2022 | Relative Total Shareholder Return Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award Calibration Percentage				100%
Variance from Award Calibration Percentage				50%
Award Cap, Percent				200%
Award Additional Cap, Percent				100%
Threshold Consecutive Trading Days | $				20
Long Term Incentive Plan Fiscal 2022 | Time Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of warrants vesting				33%
Long Term Incentive Plan Fiscal 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of award components | item			2
Common stock, shares reserved for issuance						1,095,657
Restricted Stock Awards and Units, Granted, Shares			2,249,890
Long Term Incentive Plan Fiscal 2023 | Relative Total Shareholder Return Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award Calibration Percentage			100%
Variance from Award Calibration Percentage			50%
Award Cap, Percent			200%
Award Additional Cap, Percent			100%
Threshold Consecutive Trading Days | $			60
Long Term Incentive Plan Fiscal 2023 | Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Granted, Shares			1,124,953
Percentage of Target Performance						100%
Long Term Incentive Plan Fiscal 2023 | Time Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of warrants vesting			33%
Restricted Stock Awards and Units, Granted, Shares			1,124,937
Long Term Incentive Plan Fiscal 2023 | Time Based Awards | Salaried Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of warrants vesting						33%
Restricted Stock Awards and Units, Granted, Shares						3,413,299
Long Term Incentive Plan Fiscal 2023 | Performance and Time Based Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock or Unit Expense weighted average period			3 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock awards, general vesting period						4 years
Maximum | Third Amended and Restated 2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares to be issued on exercise of stock options		1,833,333
Additional number of shares authorized		6,000,000
Number of shares authorized		18,333,333
Maximum | Third Amended and Restated 2018 Omnibus Incentive Plan | Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance						1,481,395
Maximum | Amended and Restated 2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares that can be purchased by individual participant		1,000
Additional number of shares authorized		500,000
Number of shares authorized		541,667
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock awards, general vesting period						3 years

Benefit Plans - Schedule of Sha

Benefit Plans - Schedule of Share-Based Compensation Reflected in Consolidated Statement of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 11,588	$ 6,580	$ 4,197
Costs of Revenues
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	1,502	706	493
Administrative and Selling Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	8,657	5,418	3,593
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 1,429	$ 456	$ 111

Benefit Plans - Summary of RSA

Benefit Plans - Summary of RSA and RSU Activity (Details) - $ / shares		12 Months Ended
	Dec. 05, 2022	Oct. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Outstanding, Shares, Beginning Balance		2,520,881
Restricted Stock Awards and Units, Vested, Shares		(1,207,881)
Restricted Stock Awards and Units, Forfeited, Shares		(433,051)
Restricted Stock Awards and Units, Outstanding, Shares, Ending Balance		6,543,138
Restricted Stock Awards and Units, Outstanding, Weighted-Average Fair Value, Beginning Balance		$ 7.93
Restricted Stock Awards and Units, Vested, Weighted-Average Fair Value		5.39
Restricted Stock Awards and Units, Forfeited, Weighted-Average Fair Value		5.01
Restricted Stock Awards and Units, Outstanding, Weighted-Average Fair Value, Ending Balance		$ 5.06
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Granted, Shares		1,124,953
Restricted Stock Awards and Units, Granted, Weighted-Average Fair Value	$ 5.50	$ 5.50
Time Based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Awards and Units, Granted, Shares		4,538,236
Restricted Stock Awards and Units, Granted, Weighted-Average Fair Value		$ 3.36

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Income Taxes
U.S.	$ (95,910)	$ (145,439)	$ (96,959)
Foreign	(11,565)	(974)	(4,064)
Loss before provision for income taxes	$ (107,475)	$ (146,413)	$ (101,023)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Income Taxes
Income tax expense (benefit)	$ 581	$ 819	$ 2
Franchise tax expense	900	$ 1,000	$ 500
federal net operating loss carryforwards	481,500
State NOL carryforwards	516,400
State tax credits	$ 11,700

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Federal Statutory Income Tax Rate To Effective Income Tax Rate (Details)	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Income Taxes
Statutory federal income tax rate	(21.00%)	(21.00%)	(21.00%)
State taxes, net of Federal benefits	(3.20%)	(3.60%)	(5.20%)
Foreign withholding tax	0.50%	0.60%	0.20%
Net operating loss expiration, impairment and true-ups	6.10%	8.70%	3.60%
Nondeductible expenditures	2.10%	1.40%	1.90%
Change in tax rates	2.80%	0.30%	(1.30%)
Fair value adjustment on warrants			3.30%
Other, net	0.60%	0.70%
Deferred only adjustment	(0.10%)	(0.10%)	0.80%
Valuation allowance	12.70%	13.60%	17.90%
Effective income tax rate	0.50%	0.60%	0.20%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Income Taxes
Deferred tax assets, Compensation and benefit accruals	$ 6,026	$ 8,523
Deferred tax assets, Bad debt and other allowances	1,945	2,453
Deferred tax assets, Capital loss and tax credit carry-forwards	14,701	14,310
Deferred tax assets, Net operating losses (domestic and foreign)	139,900	123,825
Deferred tax assets, Deferred license revenue	1,148	1,548
Deferred tax assets, Accumulated depreciation	14,051	20,229
Deferred tax assets, Grant revenue	323	475
Deferred tax assets, Excess business interest	6,406	10,424
Deferred tax assets, Operating lease liabilities	1,879	2,085
Deferred tax assets, Capitalized research and development	9,729
Deferred tax assets, Mark to market	987
Deferred tax assets, Other	4
Gross deferred tax assets:	197,099	183,872
Deferred tax assets, Valuation allowance	(193,477)	(180,048)
Deferred tax assets after valuation allowance	3,622	3,824
Deferred tax liability, In process research and development	(2,293)	(2,475)
Deferred tax liability Right of use assets	(1,600)	(1,809)
Deferred tax liability Other	(9)
Net deferred tax liability	$ (280)	$ (460)

Loss Per Share - Schedule of Ca

Loss Per Share - Schedule of Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Numerator
Net loss attributable to FuelCell Energy, Inc.	$ (107,568)	$ (142,722)	$ (101,055)
Series B preferred stock dividends	(3,200)	(3,200)	(3,200)
Net loss attributable to common stockholders	$ (110,768)	$ (145,922)	$ (104,255)
Denominator
Weighted average common shares outstanding - basic	419,747,796	383,139,140	334,742,346
Weighted average common shares outstanding - diluted	419,747,796	383,139,140	334,742,346
Net loss to common stockholders per share - basic	$ (0.26)	$ (0.38)	$ (0.31)
Net loss to common stockholders per share - diluted	$ (0.26)	$ (0.38)	$ (0.31)
Series B Preferred Stock
Numerator
Series B preferred stock dividends	$ (3,200)	$ (3,200)	$ (3,200)

Loss Per Share - Schedule of Po

Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from the Diluted Loss Per Share Calculation (Details) - shares	1 Months Ended	12 Months Ended
	Mar. 31, 2005	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from diluted loss per share calculation		6,599,266	2,578,949	3,553,868
Series B Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred stock, dividend rate, percentage	5%	5%	5%	5%
Series C Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from diluted loss per share calculation				950,102
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from diluted loss per share calculation		18,291	20,231	22,388
Unvested Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from diluted loss per share calculation		6,543,138	2,520,881	2,543,541
5% Series B Cumulative Convertible Perpetual Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from diluted loss per share calculation		37,837	37,837	37,837

Restricted Cash - Additional In

Restricted Cash - Additional Information (Details) - USD ($) $ in Millions	Oct. 31, 2023	Oct. 31, 2022
Restricted Cash
Restricted cash and cash equivalents	$ 49.6	$ 23

Restricted Cash - Summary of Al

Restricted Cash - Summary of Allocation of Restricted Cash (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Oct. 31, 2022
Debt Instrument [Line Items]
Cash Restricted For Outstanding Letters Of Credit	$ 14,152	$ 4,993
Cash Restricted for PNC Sale-Leaseback Transactions		5,010
Cash Restricted for Crestmark Sale-Leaseback Transactions	2,901	2,894
Bridgeport Fuel Cell Park Project Debt Service And Performance Reserves		8,746
Other	3,579	1,346
Total Restricted Cash	49,624	22,989
Restricted Cash and Cash Equivalents - Short-Term	(5,159)	(4,423)
Restricted cash and cash equivalents - long-term	44,465	$ 18,566
OpCo Financing Facility
Debt Instrument [Line Items]
Debt Service and Performance Reserves related to Financing	19,698
Senior And Subordinated Back-Leverage Loan Facilities
Debt Instrument [Line Items]
Debt Service and Performance Reserves related to Financing	$ 9,294

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
	Oct. 31, 2023 USD ($)	Oct. 31, 2023 USD ($) project MW
Commitments And Contingencies [Line Items]
Derivative gain, net | $		$ 4.1
Total number of projects | project		3
Recorded unconditional purchase obligation | $	$ 102.2	$ 102.2
Tulare Biomart Project
Commitments And Contingencies [Line Items]
Term for procuring fuel	20 years
LIPA project
Commitments And Contingencies [Line Items]
Term for procuring fuel	7 years
LIPA project | Maximum
Commitments And Contingencies [Line Items]
Term for procuring fuel	18 years
Toyota Project
Commitments And Contingencies [Line Items]
Fuel Supply Contract Term		2 years
Toyota
Commitments And Contingencies [Line Items]
Term for procuring fuel		2 years
Toyota | Maximum
Commitments And Contingencies [Line Items]
Term for procuring fuel		20 years
Derby Project
Commitments And Contingencies [Line Items]
Fuel Supply Contract Term		6 years
Derby Project 14.0 Mega Watt
Commitments And Contingencies [Line Items]
Operating power plant capacity		14
Term for procuring fuel		6 years
Derby Project 14.0 Mega Watt | Maximum
Commitments And Contingencies [Line Items]
Term for procuring fuel		20 years
Derby Project 2.8 Mega Watt
Commitments And Contingencies [Line Items]
Operating power plant capacity		2.8
Bridgeport
Commitments And Contingencies [Line Items]
Operating power plant capacity		14.9

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Schedule of Cash Flow, Supplemental Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Supplemental Cash Flow Information
Cash interest paid	$ 3,088	$ 1,556	$ 5,765
Income taxes paid	6	2	6
Noncash financing and investing activity:
Noncash reclassifications between inventory and project assets	1,987	1,260	7,052
Noncash reclassifications from inventory to fixed assets		1,552
Noncash reclassifications from other assets to project assets		2,375
Director stock compensation	225	305	275
Accrued noncontrolling interest distribution	148
Addition of operating lease liabilities	1,952		1,459
Addition of operating lease right-of-use assets	1,952		1,459
Reclassification to equity of warrant liability for warrant exercises			21,170
Noncash reduction in basis of project assets	6,330
Accrued purchase of fixed assets, cash paid to be paid in subsequent period	1,646	4,396	1,537
Accrued purchase of project assets, cash to be paid in subsequent period	$ 4,515	$ 6,444	$ 6,707

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (107,568)	$ (142,722)	$ (101,055)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Oct. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false