Fluence Energy (FLNC) 10-Q 13 May 22 2022 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Mar. 31, 2022	May 11, 2022
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-40978
Entity Registrant Name	Fluence Energy, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	87-1304612
Entity Address, Address Line One	4601 Fairfax Drive
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Arlington
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22203
City Area Code	(833)
Local Phone Number	358-3623
Title of 12(b) Security	Class A common stock, $0.00001 par value
Trading Symbol	FLNC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Central Index Key	0001868941
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false
Class A common stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		55,170,050
Common Class B-1
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		117,173,390

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($)	Mar. 31, 2022	Sep. 30, 2021
Current assets
Cash and cash equivalents	$ 651,948,000	$ 36,829,000
Restricted cash	70,740,000	1,240,000
Trade receivables, net of allowances ($86 and $90 at March 31, 2022 and September 30, 2021, respectively)	126,234,000	46,664,000
Unbilled receivables	81,300,000	101,975,000
Receivables from related parties	37,034,000	33,362,000
Advances to suppliers	49,270,000	9,741,000
Inventory, net	351,985,000	389,787,000
Other current assets	47,409,000	41,917,000
Total current assets	1,415,920,000	661,515,000
Non-current assets
Property and equipment, net	8,496,000	8,206,000
Intangible assets, net	34,439,000	36,057,000
Goodwill	9,168,000	9,176,000
Deferred income tax asset	1,184,000	1,184,000
Advances to suppliers	26,250,000	0
Debt issuance cost	2,954,000	222,000
Other non-current assets	2,525,000	1,315,000
Total non-current assets	85,016,000	56,160,000
Total assets	1,500,936,000	717,675,000
Current liabilities
Accounts payable	121,620,000	158,366,000
Deferred revenue	222,815,000	71,365,000
Borrowing from line of credit	0	50,000,000
Borrowing from related parties	0	50,000,000
Personnel related liabilities	15,935,000	12,861,000
Accruals and provisions	217,125,000	186,143,000
Payables and deferred revenue with related parties	176,673,000	227,925,000
Taxes payable	17,275,000	12,892,000
Other current liabilities	3,334,000	1,941,000
Total current liabilities	774,777,000	771,493,000
Non-current liabilities
Personnel related liabilities	397,000	1,607,000
Accruals and provisions	305,000	774,000
Total non-current liabilities	702,000	2,381,000
Total liabilities	775,479,000	773,874,000
Commitments and contingencies (See Note 12)
Mezzanine equity (0 and 18,493,275 units issued and outstanding as of March 31, 2022 and September 30, 2021, respectively)		117,235,000
Stockholders’ Equity / Members’ Deficit
Members’ capital contributions		106,152,000
Preferred stock, $0.00001 per share, 10,000,000 shares authorized; no shares issued and outstanding as of March 31, 2022	0
Additional paid-in capital	289,428,000
Accumulated other comprehensive loss	(2,000)	(285,000)
Accumulated deficit	(47,990,000)	(279,301,000)
Total stockholder's equity attributable to Fluence Energy, Inc	241,437,000
Total stockholder's equity attributable to Members' deficit		(173,434,000)
Non-controlling interest	484,020,000
Total stockholders' equity	725,457,000
Total liabilities, stockholders’ equity, members’ deficit, and mezzanine equity	1,500,936,000	$ 717,675,000
Class A common stock
Stockholders’ Equity / Members’ Deficit
Common stock	0
Class B-1 common stock
Stockholders’ Equity / Members’ Deficit
Common stock	1,000
Class B-2 common stock
Stockholders’ Equity / Members’ Deficit
Common stock	$ 0

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (PARENTHETICAL) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Trade receivable, allowance for credit loss	$ 86	$ 90
Mezzznine equity, shares issued (in shares)	0
Mezzanine equity, shares outstanding (in shares)		18,493,275
Preferred stock, par value (in usd per share)	$ 0.00001
Preferred stock, shares authorized (in shares)	10,000,000
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Class A common stock
Common stock, par value (in usd per share)	$ 0.00001
Common stock, shares authorized (in shares)	1,200,000,000
Common stock, shares issued (in shares)	54,143,275
Common stock, shares outstanding (in shares)	54,143,275
Class B-1 common stock
Common stock, par value (in usd per share)	$ 0.00001
Common stock, shares authorized (in shares)	300,000,000
Common stock, shares issued (in shares)	117,173,390
Common stock, shares outstanding (in shares)	117,173,390
Class B-2 common stock
Common stock, par value (in usd per share)	$ 0.00001
Common stock, shares authorized (in shares)	300,000,000
Common stock, shares issued (in shares)	0
Common stock, shares outstanding (in shares)	0

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Total revenue	$ 342,724	$ 98,133	$ 517,611	$ 214,366
Cost of goods and services	357,472	97,118	585,508	208,552
Gross (loss) profit	(14,748)	1,015	(67,897)	5,814
Operating expenses:
Research and development	13,340	8,367	24,098	12,511
Sales and marketing	6,191	5,180	19,250	9,921
General and administrative	25,237	8,276	56,438	14,998
Depreciation and amortization	1,493	1,162	2,920	2,232
Interest expense	676	386	1,358	475
Other income (expense), net	1,109	(667)	283	(511)
Loss before income taxes	(60,576)	(23,023)	(171,678)	(34,834)
Income tax expense	128	509	486	1,194
Net loss	(60,704)	(23,532)	(172,164)	(36,028)
Less: Net loss attributable to the non-controlling interest	(41,519)	(23,532)	(124,174)	(36,028)
Net loss attributable to Fluence Energy, Inc.	$ (19,185)		$ (47,990)
Weighted average number of Class A common shares outstanding
Weighted average number of Class A common shares outstanding, basic (in shares)	54,143,275		54,143,275
Weighted average number of Class A common shares outstanding, diluted (in shares)	54,143,275		54,143,275
Loss per share of Class A common stock
Loss per share of Class A common stock, basic (in usd per share)	$ (0.35)		$ (0.89)
Loss per share of Class A common stock, diluted (in usd per share)	$ (0.35)		$ (0.89)
Foreign currency translation gain (loss), net of income tax (expense) benefit of $0 in each period	$ (20)	122	$ 279	(729)
Total other comprehensive income (loss)	(20)	122	279	(729)
Total comprehensive loss	(60,724)	(23,410)	(171,885)	(36,757)
Comprehensive loss attributable to non-controlling interest	(41,533)	(23,410)	(124,103)	(36,757)
Total comprehensive loss attributable to Fluence Energy, Inc.	(19,191)		(47,782)
Consolidated Entities, Excluding Affiliated Entities
Total revenue	115,798	67,886	142,852	165,714
Affiliated Entity
Total revenue	$ 226,926	$ 30,247	$ 374,759	$ 48,652

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENISVE LOSS (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Foreign currency translation gain (loss), income tax (expense) benefit	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY, MEMBERS'' DEFICIT, AND MEZZANINE EQUITY (UNAUDITED) - USD ($)	Total	Class A	Members’ capital contributions	Common StockClass A	Common StockClass B	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income	Non-Controlling interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, LLC	$ (17,225,000)		$ 99,872,000				$ (117,298,000)	$ 201,000
Beginning balance, LLC (in units) at Sep. 30, 2020			7,920,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(36,028,000)						(36,028,000)
Total other comprehensive income (loss)	(729,000)							(729,000)
Ending Balance, LLC at Mar. 31, 2021	(53,982,000)		$ 99,872,000				(153,326,000)	(528,000)
Ending balance, LLC (in units) at Mar. 31, 2021			7,920,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, LLC	(30,572,000)		$ 99,872,000				(129,794,000)	(650,000)
Beginning balance, LLC (in units) at Dec. 31, 2020			7,920,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(23,532,000)						(23,532,000)
Total other comprehensive income (loss)	122,000							122,000
Ending Balance, LLC at Mar. 31, 2021	(53,982,000)		$ 99,872,000				(153,326,000)	(528,000)
Ending balance, LLC (in units) at Mar. 31, 2021			7,920,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, LLC	(53,982,000)		$ 99,872,000				(153,326,000)	(528,000)
Beginning Balance, LLC	(173,434,000)		106,152,000			$ 0	(279,301,000)	(285,000)
Beginning balance at Sep. 30, 2021	117,235,000		117,235,000
Increase (Decrease) in Temporary Equity [Roll Forward]
Effect of the Transactions			(117,235,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(172,164,000)
Total other comprehensive income (loss)	279,000
Effect of the Transactions	(117,235,000)		$ (106,152,000)	$ 0	$ (1,000)	24,091,000	(279,301,000)	(75,000)	$ 31,899,000
Effect of the Transactions (in shares)				18,493,275	117,173,390
Issuance of Class A Common stock in IPO, net of issuance costs	935,762,000					295,740,000			640,022,000
Issuance of Class A Common stock in IPO, net of issuance costs (in shares)				35,650,000
Activity under stock compensation plan	17,779,000					17,779,000			0
Ending balance (in shares) at Mar. 31, 2022		54,143,275		54,143,275	117,173,390
Ending balance at Mar. 31, 2022	725,457,000			$ 0	$ 1,000	289,428,000	(47,990,000)	(2,000)	484,020,000
Beginning balance (in shares) at Dec. 31, 2021				54,143,275	117,173,390
Beginning balance at Dec. 31, 2021	778,100,000			$ 0	$ 1,000	281,347,000	(28,805,000)	4,000	525,553,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(60,704,000)						(19,185,000)		(41,519,000)
Total other comprehensive income (loss)	(20,000)							(6,000)	(14,000)
Activity under stock compensation plan	8,081,000					8,081,000			0
Ending balance (in shares) at Mar. 31, 2022		54,143,275		54,143,275	117,173,390
Ending balance at Mar. 31, 2022	$ 725,457,000			$ 0	$ 1,000	$ 289,428,000	$ (47,990,000)	$ (2,000)	$ 484,020,000

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY, MEMBERS'' DEFICIT, AND MEZZANINE EQUITY (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement of Stockholders' Equity [Abstract]
Other comprehensive loss, tax	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (172,164)	$ (36,028)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,920	2,232
Amortization of debt issuance costs	343	0
Stock based compensation expense	27,605	0
Benefit on loss contracts	(6,261)	(1,858)
Changes in operating assets and liabilities:
Trade receivables	(79,570)	(22,287)
Unbilled receivables	20,675	(8,223)
Receivables from related parties	(3,672)	17,402
Advances to suppliers	(65,779)	(13,184)
Inventory, net	37,802	(304,707)
Other current assets	(7,391)	(2,554)
Other non-current assets	135	4
Accounts payable	(30,426)	58,851
Payables and deferred revenue with related parties	(51,252)	95,541
Deferred revenue	151,450	85,060
Current accruals and provisions	37,243	50,232
Taxes payable	4,383	(4,566)
Other current liabilities	373	457
Other non-current liabilities	(1,679)	488
Cash settled for stock based compensation	(5,731)	0
Net cash used in operating activities	(140,996)	(83,140)
Investing activities
Purchase of equity securities	(1,124)	0
Cash paid for business acquisition	0	(18,000)
Purchase of property and equipment	(1,271)	(2,227)
Net cash used in investing activities	(2,395)	(20,227)
Financing activities
Proceeds from issuance of Class A common stock sold in the IPO, net of underwriting discounts	947,991	0
Payment of IPO costs	(10,330)	0
Payment of transaction cost related to issuance of membership units	(6,320)	0
Payment of debt issuance costs	(3,297)	0
Repayment of promissory notes – related parties	(50,000)	0
Borrowing from line of credit	0	38,000
Repayment to line of credit	(50,000)	0
Other	0	2,236
Net cash provided by financing activities	828,044	40,236
Effect of exchange rate changes on cash and cash equivalents	(34)	(791)
Net increase (decrease) in cash and cash equivalents	684,619	(63,922)
Cash, cash equivalents, and restricted cash as of the beginning of the period	722,688	31,129
Cash, cash equivalents, and restricted cash as of the end of the period	38,069	95,051
Supplemental Cash Flows Information
Interest Paid	503	271
Cash paid for income taxes	614	4,124
Reclassification of deferred offering costs to additional paid-in capital	$ 1,899	$ 0

Organization and Operations

Organization and Operations	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Operations	Organization and Operations Fluence Energy, Inc., a Delaware corporation (“the Company”), was formed on June 21, 2021. We conduct our business operations through Fluence Energy, LLC and its direct and indirect subsidiaries. Fluence Energy, LLC was formed on June 30, 2017 as a joint venture between Siemens Industry, Inc. (“Siemens Industry”), an indirect subsidiary of Siemens AG (“Siemens”), and AES Grid Stability, LLC (“AES Grid Stability”), an indirect subsidiary of the AES Corporation (“AES”), and commenced operations on January 1, 2018. We refer to Siemens Industry and AES Grid Stability as the “Founders” in this Quarterly Report on Form 10-Q (this “Report”). Fluence Energy, LLC, along with its wholly owned subsidiaries, is primarily engaged in the construction and sale of battery-based energy storage products and providing operational services and artificial intelligence (AI)-enabled digital applications (“Fluence IQ”) for renewables and storage throughout the world, including the Americas, EMEA, and Asia Pacific regions. Except where the context clearly indicates otherwise, “Fluence,” “we,” “us,” “our” or the “Company” refers to Fluence Energy, Inc. and its wholly owned subsidiaries. The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer. The Company’s CODM reviews financial information on a condensed consolidated basis for purposes of making operating decisions, allocating resources, and evaluating financial performance. As such, the Company has determined that it operates in one operating segment, which corresponds to one reportable segment. QFH’s Investment in Fluence Energy, LLC On December 27, 2020, Fluence Energy, LLC entered into an agreement with QIA Florence Holdings LLC (“QFH” or the “Blocker Company”) for a $125.0 million investment. QFH was issued 18,493,275 Class B units of Fluence Energy, LLC. QFH is an affiliate of the Qatar Investment Authority (“QIA”), the sovereign wealth fund of Qatar, and its subsidiaries and affiliates. At September 30, 2021, the investment was recognized at carrying value within mezzanine equity on the consolidated balance sheets. As part of the transactions related to our initial public offering closed on November 1, 2021, QFH elected to convert their Class B units to the common stock of Fluence Energy Inc., which is a conversion available to all of the holders of Fluence Energy, LLC Class A and Class B units. Accordingly, as of March 31, 2022, no mezzanine equity is recorded on the condensed consolidated balance sheets. Initial Public Offering and Related Transactions On November 1, 2021, the Company completed an initial public offering (the “IPO”) and a series of organization transactions (collectively with the IPO, the “Transactions”), in which the Company issued and sold 35,650,000 shares of its Class A common stock, par value $0.00001 per share, at the public offering price of $28.00 per share, which includes the exercise by the underwriters of their option to purchase an additional 4,650,000 shares of the Company’s Class A common stock. The net proceeds to the Company from the IPO were $935.8 million, after deducting underwriting discounts and offering expenses paid by the Company. Immediately following the consummation of the Transactions: • Fluence Energy, Inc. became a holding company. As the sole managing member of Fluence Energy, LLC, Fluence Energy, Inc. controls the business and affairs of Fluence Energy, LLC and its direct and indirect subsidiaries; • Fluence Energy, Inc. owns, directly or indirectly, 54,143,275 LLC Interests in Fluence Energy, LLC, representing approximately 31.6% of the economic interest in Fluence Energy, LLC; • the Founders own 117,173,390 LLC Interests in Fluence Energy, LLC, representing approximately 68.4% of the economic interest in Fluence Energy, LLC; • the investors in our IPO own 35,650,000 shares of Class A common stock of Fluence Energy, Inc., representing approximately 65.8% of the economic interest in Fluence Energy, Inc.; Qatar Holding LLC, the owner of the original Blocker Company owns 18,493,275 shares of Class A common stock of Fluence Energy, Inc., representing approximately 34.2% of the economic interest in Fluence Energy, Inc.; and • the Founders own 117,173,390 shares of Class B-1 common stock of Fluence Energy, Inc. Refer to Note 19 - Subsequent Events

Summary of Significant Accounti

Summary of Significant Accounting Policies and Estimates	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies and Estimates	Summary of Significant Accounting Policies and Estimates Principles of Accounting and Consolidation As the sole managing member of Fluence Energy, LLC, Fluence Energy, Inc. operates and controls all the business and affairs of Fluence Energy, LLC and, through Fluence Energy, LLC and its direct and indirect subsidiaries, conducts the Company’s business. Fluence Energy, LLC is a variable interest entity, of which the Fluence Energy, Inc. beneficially owns a 31.6% interest as of March 31, 2022. For accounting purposes, Fluence Energy, Inc. is considered the primary beneficiary and therefore consolidates the results of Fluence Energy, LLC and its direct and indirect subsidiaries. Prior to the IPO, Fluence Energy, Inc. had no operations and had no asset or liabilities. Accordingly, financial results, balances, and other information included herein for periods prior to the IPO are reflective of Fluence Energy, LLC. The accompanying condensed consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and under the rules of the U.S. Securities and Exchange Commission (the “SEC”). The accompanying condensed consolidated financial statements include the accounts of Fluence Energy Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Non-Controlling Interest The non-controlling interest on the condensed consolidated statements of operations and comprehensive loss represents the portion of earnings or loss attributable to the economic interest in Fluence Energy, LLC, held by the Founders. For the six months ended March 31, 2022, the net loss of Fluence Energy, LLC prior to the date of the Transactions has been attributed to the non-controlling interest, and the net loss of Fluence Energy, LLC subsequent to the date of the Transactions has been allocated between Fluence Energy, Inc. and the non-controlling interest based on the respective ownership percentages of Fluence Energy, LLC held by Fluence Energy, Inc. and the Founders. Non-controlling interest on the condensed consolidated balance sheets represents the portion of net assets of the Fluence Energy, LLC attributable to the Founders, based on the portion of the LLC Interests owned by such shareholders. As of March 31, 2022, the non-controlling interest was 68.4%. Unaudited Interim Financial Information The accompanying condensed consolidated financial statements as of March 31, 2022, and for the three and six months ended March 31, 2022 and 2021 are unaudited. These financial statements should be read in conjunction with the Company’s audited financial statements included in our 2021 Annual Report. In our opinion, such unaudited financial statements reflect all adjustments, including normal recurring items, that are necessary for the fair statement of the Company’s financial position as of March 31, 2022, the results of its operations for the three and six months ended March 31, 2022 and 2021, and its cash flows for the six months ended March 31, 2022 and 2021. The financial data and other information disclosed in these notes related to the three and six months ended March 31, 2022 and 2021 are also unaudited. The results for the three and six months ended March 31, 2022 and 2021 are not necessarily indicative of results for the full year ending September 30, 2022 and 2021, any other interim periods, or any future year or period. The balance sheet as of September 30, 2021 included herein was derived from the audited financial statements as of that date. Certain disclosures have been condensed or omitted from the interim financial statements. For a complete description of our significant accounting policies, refer to Note 2 - Summary of Significant Accounting Policies and Estimates to the audited consolidated financial statements included in our 2021 Annual Report. We include herein certain updates to those policies. Reclassification Certain prior year amounts have been reclassified from “Cost of goods and services” to “Sales and marketing” and “General and administrative” to conform to current period presentation on the condensed consolidated statements of operations and comprehensive loss. Cash, Cash Equivalents, and Restricted Cash Cash and cash equivalents include cash on-hand and highly liquid investments readily convertible to cash, with an original maturity of 90 days or less when purchased. Cash restricted for use as a result of financing or other obligations is classified separately as restricted cash on the Company’s condensed consolidated balance sheets. The following table provides a reconciliation of cash, cash equivalents, and restricted cash as shown in the Company’s condensed consolidated statements of cash flows. in thousands March 31, 2022 March 31, 2021 Cash and cash equivalents $ 651,948 $ 29,883 Restricted cash 70,740 1,246 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 722,688 $ 31,129 Restricted cash consisted of the following: in thousands March 31, 2022 March 31, 2021 Collateral for credit card program $ 1,422 $ 925 Collateral for outstanding bank guarantees 69,318 321 Total restricted cash $ 70,740 $ 1,246 Fair Value Measurements The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs and to minimize the use of unobservable inputs. The following fair value hierarchy, defined by ASC 820, Fair Value Measurements , is used to classify assets and liabilities based on the observable inputs and unobservable inputs used to value the assets and liabilities: Level 1—Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2—Pricing inputs are other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 2 inputs include those financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted prices, time value, volatility factors, and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Level 3—Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value from the perspective of a market participant. The Company does not have significant recurring Level 3 fair value measurements. The Company’s cash equivalents include term deposits with original maturity of less than three months and are recorded at amortized cost. Fair value of cash equivalents approximates the carrying amount using Level 2 inputs. The carrying amounts of trade receivables, accounts payable and short-term debt obligations approximate fair values due to their short maturities using Level 2 inputs. Loss per Share Basic net loss per share of Class A common stock is computed by dividing net loss attributable to Class A common stockholders by the weighted average number of shares of Class A common stock outstanding during the period. Diluted net loss per share of Class A common stock is computed by adjusting the net loss available to Class A common stockholders and the weighted-average shares of Class A common stock outstanding to give effect to potentially dilutive securities. Shares of our Class B-1 and Class B-2 common stock are not entitled to receive any distributions or dividends and have no rights to convert into Class A common stock. When a common unit of Fluence Energy, LLC is exchanged for, at the Company’s election, cash or Class A common stock by a Founder who holds shares of our Class B-1 or Class B-2 common stock, such Founder will be required to surrender a share of Class B-1 or Class B-2 common stock, as the case may be, which we will cancel for no consideration. In the event of cash settlement, the Company is required to issue new shares of Class A common stock and use the proceeds from the sale of these newly-issued shares of Class A common stock to fully fund the cash settlement. Therefore, we did not include shares of our Class B-1 or Class B-2 common stock in the computation of basic loss per share. As we have incurred losses for all periods presented, diluted loss per share is equal to basic loss per share because the effect of potentially dilutive securities would be antidilutive. The potentially dilutive securities that were excluded consist of 117,173,390 Class B-1 common shares, 11,286,991 outstanding stock options, 2,167,290 outstanding phantom units, and 979,608 outstanding restricted stock units as of March 31, 2022. All earnings prior to and up to November 1, 2021, the date of completion of the IPO, were entirely allocable to non-controlling interest and, as a result, loss per share information is not applicable for reporting periods prior to this date. Consequently, only the net loss allocable to Fluence Energy, Inc. from the period subsequent to November 1, 2021 is included in the net loss attributable to the stockholders of Class A common stock for the six months ended March 31, 2022. Basic and diluted net loss per share of Class A common stock for the three and six months ended March 31, 2022, respectively, have been computed as follows: In thousands, except share and per share amounts Three Months Ended March 31, 2022 Six Months Ended March 31, 2022 Net loss $ (60,704) $ (172,164) Less: Net loss attributable to the non-controlling interest (41,519) (124,174) Net loss attributable to Fluence Energy, Inc. $ (19,185) $ (47,990) Weighted average number of Class A common shares outstanding, basic and diluted 54,143,275 54,143,275 Loss per share of Class A common stock, basic and diluted $ (0.35) $ (0.89) Recent Accounting Standards Adopted No new accounting standards were adopted during the six months ended March 31, 2022. Recent Accounting Standards Not Yet Adopted The following table presents accounting standards not yet adopted: Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2016-02, Leases (Topic 842) In February 2016, the Financial Accounting Standard Board (“FASB”) issued ASU 2016-02, which supersedes existing guidance on accounting for leases in ASC 840, Leases . This standard requires all leases to be recognized on the consolidated balance sheet. FASB has issued several amendments to ASU 2016-02, including ASU 2018-11, Leases (Topic 842) : Targeted Improvements that introduced an additional transition method permitting an entity to initially apply the new lease standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ASU 2016-02 includes optional practical expedients intended to reduce the cost and complexity to implement the new lease standard, such as an option to maintain the current lease classification for all existing lease arrangements and the option to use hindsight in evaluating lessee options to extend or terminate a lease. Early application is permitted. As an emerging growth company (an “EGC”), the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2021. The Company’s existing lease population is mainly comprised of operating leases for office space. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2016-13, Financial Instruments—Credit Losses (Topic 326) In February 2016, FASB issued ASU 2016-13, which updates the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (“CECL”) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowance for losses. There are various transition methods available upon adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2019-12, Income Taxes (Topic 740) : Simplifying the Accounting for Income Taxes In December 2019, FASB issued ASU 2019-12, which removes certain exceptions related to the approach for intraperiod tax allocations, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. The guidance also clarifies and simplifies other areas of ASC 740. Certain amendments must be applied on a prospective basis, certain amendments must be applied on a retrospective basis, and certain amendments must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings/(deficit) in the period of adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting December 15, 2021, and for interim periods beginning after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting (Topic 848) In March 2020, FASB issued ASU 2020-04, which provides optional expedients and exceptions for applying U.S. GAAP to transactions affected by reference rate (e.g., LIBOR) reform if certain criteria are met, for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The ASU is effective as of March 12, 2020 through December 31, 2022. The Company is currently evaluating transactions or contract modifications occurring as a result of reference rate reform and determining whether to apply the optional guidance on an ongoing basis. The ASU is currently not expected to have a material impact on our consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Our revenue is primarily derived from sales of our energy storage products. The following table presents the Company’s revenue disaggregated by geographical region. Revenues are attributed to regions based on location of customers. In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Americas (North, Central and South America) $ 257,492 $ 67,965 $ 399,325 $ 112,117 APAC (Asia Pacific) 21,250 25,540 38,059 87,938 EMEA (Europe, Middle-East and Africa) 63,982 4,628 80,227 14,311 Total $ 342,724 $ 98,133 $ 517,611 $ 214,366 Deferred Revenue Deferred revenue represents the excess billings over the amount of revenue recognized to date. Deferred revenue from related parties is included in payables and deferred revenue with related parties on the Company’s condensed consolidated balance sheets. The following table provides information about deferred revenue from contracts with customers: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Deferred revenue beginning of period $ 145,765 $ 154,450 $ 71,365 $ 123,841 Additions 138,135 120,473 191,562 167,988 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (61,085) (66,022) (40,112) (82,928) Deferred revenue end of period $ 222,815 $ 208,901 $ 222,815 $ 208,901 In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Deferred revenue from related parties beginning of period $ 200,085 $ 44,281 $ 220,122 $ 11,425 Additions 120,097 70,903 153,078 103,831 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (148,716) (3,105) (201,734) (3,177) Deferred revenue from related parties end of period $ 171,466 $ 112,079 $ 171,466 $ 112,079 Customer and Supplier Concentration For the six months ended March 31, 2022, the Company had one customer that accounted for approximately 70% of total revenue. For the six months ended March 31, 2021, our top three customers, in the aggregate, accounted for approximately 77% of total revenue. The Company has a limited number of suppliers of batteries, which is a major component of energy storage products. Remaining Performance Obligations The Company’s remaining performance obligations (“backlog”) represent the unrecognized revenue value of its contract commitments, which include deferred revenue and amounts that will be billed and recognized as revenue in future periods. The Company’s backlog may vary significantly each reporting period based on the timing of major new contract commitments and the backlog may fluctuate with currency movements. In addition, the Company’s customers have the right, under some circumstances, to terminate contracts or defer the timing of its services and their payments to the Company. As of March 31, 2022, the Company had a total of $2,150.1 million of remaining performance obligations related to our contractual commitments, of which we expect to recognize 91% in revenue in the next five years and the remainder after five years. Variable Consideration As of March 31, 2022 and September 30, 2021, the transaction prices of our active energy solution contracts have been reduced to reflect variable consideration of $52.1 million and $52.8 million, respectively.

Business Combinations

Business Combinations	6 Months Ended
	Mar. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Business Combinations	Business Combinations During October 2020, the Company acquired the assets and assumed the liabilities of a US based software and digital intelligence platform. The acquisition has offered new capabilities, amplified and extended the Company’s energy storage product line, enabling customers to maximize the value of energy storage and renewables while accelerating grid decarbonization. The acquisition price of $18.0 million was fully paid with cash, and was adjusted for an immaterial amount to account for changes in net working capital adjustments. The acquisition represents a business combination under ASC 805 Business Combinations. The Company has included the financial results of the acquisition in its consolidated financial statements from the date of acquisition. Transaction costs associated with the acquisition were not significant and were expensed as incurred. The following table summarizes the aggregate fair values and estimated useful lives of the assets acquired and liabilities assumed, as of the date of the acquisition. In thousands Fair Value Estimated Useful Life Intangible assets - Developed technology $ 12,600 12 years Intangible assets - Customer relationships 780 6 years Property and equipment 171 Various Goodwill 4,449 Cash paid for acquisition $ 18,000 The fair value of developed technology was determined using the multi-period excess earnings method as developed technology is considered to be the primary revenue-generating identifiable intangible asset acquired in the acquisition. The fair value assigned to assets acquired and liabilities assumed are based on management’s estimates and assumptions. The goodwill is primarily attributed to the expanded market opportunities when integrating the acquired entity’s technology with the Company’s technology and the assembled workforce. The excess of the acquisition price over the fair value of assets acquired and liabilities assumed was recorded to goodwill. The Company expects such goodwill to be deductible for income tax purposes. Purchase accounting adjustments related to the acquisition have been completed.

Inventory, Net

Inventory, Net	6 Months Ended
	Mar. 31, 2022
Inventory Disclosure [Abstract]
Inventory, Net	Inventory, Net Inventory consisted of the following: In thousands March 31, 2022 September 30, 2021 Cost Provision Net Cost Provision Net Cubes, batteries, and other equipment (a) $ 345,650 $ (31) $ 345,619 $ 402,157 $ (12,980) $ 389,177 Shipping containers and spare parts 7,493 (1,127) 6,366 1,857 (1,247) 610 Total $ 353,143 $ (1,158) $ 351,985 $ 404,014 $ (14,227) $ 389,787 (a) Provision at September 30, 2021 included a $13.0 million loss recognized during fiscal year 2021 for inventory damaged in transit related to the 2021 cargo loss incident. During the six months ended March 31, 2022, $13.0 million of inventory was written off against the provision. Refer to Note 12 - Commitments and Contingencies for a detailed discussion of the 2021 cargo loss incident.

Other Current Assets

Other Current Assets	6 Months Ended
	Mar. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Current Assets	Other Current Assets Other current assets consisted of the following amounts: In thousands March 31, 2022 September 30, 2021 Taxes recoverable 26,574 14,049 Prepaid expenses 2,874 2,480 Advance payments 4,919 3,601 Receivable from insurance (a) 2,500 10,000 Deferred equity issuance costs — 7,103 Prepaid insurance 4,190 — Other 6,352 4,684 Total $ 47,409 $ 41,917 (a) Receivable from insurance represents insurance recoveries that are probable of collection related to the 2021 cargo loss incident. The Company collected $7.5 million receivable from insurance during the six months ended March 31, 2022. Refer to Note 12 - Commitments and Contingencies for a detailed discussion of the 2021 cargo loss incident.

Intangible Assets, Net

Intangible Assets, Net	6 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	Intangible Assets, Net Intangible assets are stated at amortized cost and consist of the following: In thousands March 31, 2022 September 30, 2021 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Patents and licenses $ 33,003 $ (10,444) $ 22,559 $ 32,982 $ (9,207) $ 23,775 Developed technology (a) 12,600 (1,575) 11,025 12,600 (1,050) 11,550 Other (a) 1,093 (238) 855 894 (162) 732 Total $ 46,696 $ (12,257) $ 34,439 $ 46,476 $ (10,419) $ 36,057 (a) The developed technology intangible assets and other intangible assets included $12.6 million and $0.8 million, respectively, related to the business acquisition discussed in Note 4 - Business Combinations. Intangible assets are amortized over their estimated useful lives on a straight-line basis. Total amortization expense for the three months ended March 31, 2022 and 2021 was $0.9 million and $0.9 million, respectively. Total amortization expense for the six months ended March 31, 2022 and 2021 was $1.8 million and $1.7 million, respectively.

Goodwill

Goodwill	6 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill No impairment was recognized for the six months ended March 31, 2022 and 2021, respectively. The following table presents the goodwill activity: In thousands Six Months Ended March 31, 2022 2021 Goodwill, Beginning of the period $ 9,176 $ 4,731 Foreign currency adjustment (8) 19 Acquisition related goodwill (a) — 4,449 Goodwill, End of the period $ 9,168 $ 9,199 (a) Refer to Note 4 - Business Combination for a further discussion of acquisition related goodwill.

Current Accruals and Provisions

Current Accruals and Provisions	6 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Current Accruals and Provisions	Current Accruals and Provisions Accruals mainly represent not yet invoiced milestones for inventory such as batteries, cubes, and inverters. According to master supply agreements between the Company and suppliers of the inventory, vendor bills are issued according to contracted billing schedules with some milestones invoiced after delivery, upon full installation and commissioning of the equipment at substantial completion and final completion project stages. Current accruals and provisions consisted of the following: In thousands March 31, 2022 September 30, 2021 Accruals $ 193,262 $ 155,963 Provisions for expected project losses 23,863 30,180 Total $ 217,125 $ 186,143

Short-term Debt

Short-term Debt	6 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Short-term Debt	Short-term Debt Revolving Credit Facility On November 1, 2021, we entered into a revolving credit facility (the “Revolver”), by and among Fluence Energy, LLC, as the borrower, Fluence Energy, Inc., as a parent guarantor, the subsidiary guarantors party thereto, the lenders party thereto and JP Morgan Chase Bank, N.A., as administrative agent and collateral agent. The Revolver is secured by a (i) first priority pledge of the equity securities of Fluence Energy, LLC and its subsidiaries and (ii) first priority security interests in, and mortgages on, substantially all tangible and intangible personal property and material fee-owned real property of Fluence Energy, LLC, the parent guarantor and each subsidiary guarantor party thereto, in each case, subject to customary exceptions and limitations. The initial aggregate amount of commitments is $190.0 million from the lenders party thereto including JP Morgan Chase Bank, N.A., Morgan Stanley Senior Funding, Inc., Bank of America, N.A., Barclays Bank PLC, and five other banks. The maturity date of the Revolver is November 1, 2025. The interest rate is either (i) the Adjusted LIBOR or Adjusted EURIBO Rate (each as defined in the Revolver) plus 3.0% or (ii) the Alternate Base Rate (as defined in the Revolver) plus 2.0% (subject to customary LIBOR replacement provisions and alternative benchmark rates including customary spread adjustments with respect to borrowings in foreign currency), at the option of Fluence Energy, LLC. Fluence Energy, LLC is required to pay to the lenders a commitment fee of 0.55% per annum on the average daily unused portion of the revolving commitments through maturity. The Revolver also provides for up to $190.0 million in letter of credit issuances, which will require customary issuance and administration fees, as well as a fronting fee payable to each issuer thereof and a letter of credit participation fee of 2.75% per annum payable to the lenders. The Revolver contains customary covenants for these types of financing, including, but not limited to, covenants that restrict our ability to incur additional indebtedness; incur liens; sell, transfer, or dispose of property and assets; make investments or acquisitions; make dividends, distributions or other restricted payments; and engage in affiliate transactions. The Revolver limits our ability to make certain payments, including dividends and distributions on Fluence Energy, LLC’s equity, Fluence Energy, Inc.’s equity and other restricted payments. In addition, we are required to maintain (i) minimum liquidity and gross revenue requirements, in each case, until consolidated EBITDA reaches $150.0 million for the most recent four fiscal quarters and we make an election, and (ii) thereafter, a maximum total leverage ratio and a minimum interest coverage ratio. Such covenants will be tested on a quarterly basis. As of March 31, 2022, we were in compliance with all such covenants or maintained availability above such covenant triggers. As of March 31, 2022, we had no borrowings under the Revolver. Line of Credit Prior to the IPO, the Company had an Uncommitted Line of Credit Agreement (“Line of Credit’) with Citibank, N.A. (“Citibank”) which allowed us to borrow an amount in aggregate not to exceed $50.0 million, with the expiration date on March 31, 2023. Outstanding borrowings from the Line of Credit were $50.0 million as of September 30, 2021. The weighted average annual interest rate of the borrowing was 2.83%. On November 1, 2021, the $50.0 million outstanding borrowings from the Line of Credit was paid off using the proceeds from our IPO, and the Line of Credit was canceled shortly thereafter. Refer to Note 13 — Related-Party Transactions for borrowings from related parties.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s provision for income taxes is based on the estimated annual effective tax rate, plus discrete items. Income tax expense was $0.1 million and $0.5 million for the three months ended March 31, 2022 and 2021, respectively. The effective tax rate for the three months ended March 31, 2022 and 2021 was (0.2)% and (2.2)%, respectively. For the three months ended March 31, 2022, the Company’s effective tax rate differs from the U.S. statutory tax rate of 21% primarily due to flow-through losses incurred prior to the IPO on November 1, 2021, flow-through losses attributable to the Founders, and valuation allowances. For the three months ended March 31, 2021, the Company’s effective tax rate differs from the U.S. statutory tax rate primarily due to foreign tax rate differentials, losses incurred by the partnership that flow through to the members, valuation allowances recorded on foreign deferred tax assets and foreign withholding taxes on royalties. Income tax expense was $0.5 million and $1.2 million for the six months ended March 31, 2022 and 2021, respectively. The effective tax rate for the six months ended March 31, 2022 and 2021 was (0.3)% and (3.4)%, respectively. For the six months ended March 31, 2022, the Company’s effective tax rate differs from the U.S. statutory tax rate of 21% primarily due to flow-through losses incurred prior to the IPO on November 1, 2021, flow-through losses attributable to the Founders, and valuation allowances. For the six months ended March 31, 2021, the Company’s effective tax rate differs from the U.S. statutory tax rate primarily due to foreign tax rate differentials, losses incurred by the partnership that flow through to the members, valuation allowances recorded on foreign deferred tax assets and foreign withholding taxes on royalties. The Company does not believe it has any significant uncertain tax positions and therefore has no unrecognized tax benefits as of March 31, 2022 and September 30, 2021, that if recognized, would affect the annual effective tax rate. As of March 31, 2022 and September 30, 2021, the Company had recorded a full valuation allowance against deferred tax assets of its German and Australian subsidiaries. Upon the IPO on November 1, 2021, Fluence Energy, Inc. became a holding company of Fluence Energy, LLC, and as a corporation, recorded deferred tax assets primarily related to its investment in the partnership. The Company determined that based on the weight of available evidence, including cumulative losses, it is more-likely-than-not that the net deferred tax assets of Fluence Energy, Inc. and Fluence Energy, LLC’s subsidiaries in Germany and Australia will not be realized and valuation allowances have been recorded against such deferred tax assets.

Commitment and Contingencies

Commitment and Contingencies	6 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments The Company has certain contractual obligations incurred in the normal course of business that require fixed and determinable payments in the future. These commitments include lease obligations and purchase commitments under master supply agreements. The Company did not have significant changes in lease contracts and purchase commitments during the six months ended March 31, 2022. During the six months ended March 31, 2022, the Company made a $60.0 million advance payment as a capacity guarantee pursuant to a purchase agreement with one of our suppliers, of which, $33.7 million and $26.3 million was recorded within “Current assets - Advances to suppliers” and “Non-current assets - Advances to suppliers”, respectively, on the condensed consolidated balance sheets. Warranties The Company is party to both assurance and service-type warranties for various lengths of time. The Company recognizes revenue for service type warranties over time using costs incurred relative to total expected costs as a measure of progress. For assurance-type warranties, the Company records an estimate of future warranty cost when the battery energy solution is transferred to the customer and the future costs of servicing the warranty are both probable and estimable. No material amount of costs for assurance type warranties have been incurred and we are not able to estimate an amount of probable future costs, thus no liability has been recorded. Legal Contingencies From time to time, the Company may be involved in litigation relating to claims that arise out of our operations and businesses and that cover a wide range of matters, including, among others, intellectual property matters, contract and employment claims, personal injury claims, product liability claims and warranty claims. The Company accrues for litigation and claims when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. It is reasonably possible that some matters could be decided unfavorably to the Company and could require the Company to pay damages or make expenditures in amounts that could be material. In aggregate, the Company estimates the range of potential losses, where estimable, related to reasonably possible material contingencies to be between $0 million and $5.0 million. The following discussion covers the Company’s potential loss contingencies as of March 31, 2022: 2021 Cargo Loss Incident On April 28, 2021, the Company was notified of an emergency aboard a vessel carrying Fluence inventory. This incident (the “Cargo Loss Incident”) resulted in damage to a portion of our cargo aboard the vessel. The Company has recorded $13.0 million provision to its inventory as of September 30, 2021 based on the net realizable value of cargo that was destroyed. During the six months ended March 31, 2022, $13.0 million of inventory was written off against the provision. In addition to the inventory losses, we have incurred and expect to incur incremental expenses related to the incident, primarily consisting of inspection costs, project cost overruns due to logistical changes, legal fees, fees to dispose of the damaged cargo, and additional cost to replace the damaged cargo. We received an aggregate of $10.0 million insurance proceeds related to non-disputed claims, $7.5 million of which was collected in October 2021 and the remaining $2.5 million was collected in April 2022. 2021 Overheating Event at Customer Facility On September 4, 2021, a 300 MW energy storage facility owned by one of our customers experienced an overheating event. Fluence served as the energy storage technology provider and installed the facility, which was completed in fiscal year 2021. No injuries were reported from the incident. Since then, the facility was taken offline as teams from Fluence, our customer, and the battery manufacturer investigate the incident. Our customer released initial findings in the second fiscal quarter of 2022 on what it contends is the root cause of the incident. At this time, Fluence cannot comment on or accept the customer’s stated findings, because Fluence’s investigation of the root cause remains ongoing, with continued participation by our customer and other parties involved. The customer’s stated findings, if ultimately confirmed and proven, could relate to certain scopes of work for which Fluence or its subcontractors could be responsible. The customer’s stated findings, however, could also relate to certain scopes of work for which other parties were responsible and/or relate to other causes. The customer has alleged that Fluence is liable for the incident but has not yet demanded a specific amount of compensation. Fluence has denied liability, pending completion of all investigations. No legal proceedings have been commenced. We are currently not able to estimate the impact, if any, that this incident may have on our reputation or financial results, or on the market adoption of our products.

Related-Party Transactions

Related-Party Transactions	6 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related-Party Transactions	Related-Party Transactions Related parties are represented by AES and Siemens, their respective subsidiaries and other entities under common control. As of March 31, 2022, AES and Siemens each holds 58,586,695 shares of Class B-1 common stock of the Company. Borrowings from Related Parties On August 11, 2021, the Company borrowed $25.0 million and $25.0 million from AES Grid Stability and Siemens Industry, respectively, in the form of subordinated promissory notes, each bearing an annual interest at 2.86%. The promissory notes were paid off in full on November 1, 2021 using proceeds from the IPO. Sales and Procurement Contracts with Related Parties Fluence signs battery-based energy storage product and related service contracts with AES, Siemens and their subsidiaries (collectively refer to as affiliates). The contract price in such contracts is similar to the price charged by us to third-party customers. Revenue from contracts with affiliates is included in “Revenue from related parties” on the Company’s condensed consolidated statements of operations and comprehensive loss. In addition, Fluence purchases material and supplies from its affiliates and records the costs in “Cost of goods and services” on the Company’s condensed consolidated statements of operations and comprehensive loss. Service Agreements with Affiliates Fluence and its affiliates have signed service agreements under which the affiliates provide certain management and administrative services to Fluence. The services include but are not limited to, treasury, information technology services, payroll and human resources services, sales and marketing services, and research and development. Cost of services are accrued monthly and included in “Payables and deferred revenue with related parties”, and “General and administrative”, “Sales and marketing”, or “Research and development” on the Company’s condensed consolidated balance sheets and statements of operations and comprehensive loss, respectively. Contract Performance Guarantees Fluence paid performance guarantee fees to its affiliates in exchange for guaranteeing Fluence’s performance obligation under certain contracts with Fluence’s customers, which are based on the affiliates’ weighted average cost for bank guarantees and their per annum cost of surety bonds with a reasonable markup. The guarantee fees are included in “Costs of goods and services” on Fluence’s condensed consolidated statements of operations and comprehensive loss. The following table presents the components of receivables from related parties and payables to related parties on the Company’s condensed consolidated balance sheets: In thousands March 31, 2022 September 30, 2021 Accounts receivable $ 4,732 $ 26,292 Unbilled receivables 32,302 7,070 Total receivables from related parties $ 37,034 $ 33,362 Accounts payable $ 881 $ 4,510 Deferred revenue 171,466 220,122 Accrued liabilities 4,326 3,293 Total payables and deferred revenue with related parties $ 176,673 $ 227,925 Unbilled receivables represent the excess of revenues recognized over billings to date on sales or service contracts with related parties. Deferred revenue represents the excess billings to date over the amount of revenue recognized to date on sales or service contracts with related parties. Receivables from related parties and payables and deferred revenue with related parties are unsecured and settlement of these balances occurs in cash. No provision has been made related to the receivables from related parties. The following table presents the related party transactions that are included the Company’s condensed consolidated statements of operations and comprehensive loss for the periods indicated: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Revenue $ 226,926 $ 30,247 $ 374,759 $ 48,652 Cost of goods and services (2,301) (8,059) (9,796) (8,486) Research and development expenses — (80) (45) (172) Sales and marketing expenses (468) (326) (1,075) (662) General and administrative expenses (171) (185) (1,362) (367) Refer to Note 15 — Supply Chain Financing for the related party guarantee associated with the supply chain financing.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Stock-Based Compensation The following table presents stock-based compensation expense by financial statement line item: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Cost of goods and services $ 749 $ — $ 4,277 $ — Research and development 1,524 — 3,337 — Sales and marketing (a) (1,987) — 4,454 — General and administrative 2,442 — 15,537 — Total $ 2,728 $ — $ 27,605 $ — (a) The reduction of stock based compensation expense for the three months ended March 31, 2022 was a result of the market-to-market adjustment of our liability classified awards which is driven by our stock price decrease during the three months ended March 31, 2022. As of September 30, 2021, the Company determined that achievement of the performance conditions related to awards granted under the 2020 Unit Option Plan and the 2020 Phantom Equity Incentive Plan (the “2020 Plans”) was not probable and therefore, no expense was recognized for unit options or phantom units during the fiscal year ended September 30, 2021. The completion of the IPO on November 1, 2021 resulted in achievement of the performance condition underlying awards granted under the 2020 Plans. Accordingly, previously unrecognized stock compensation expense was recognized during the six months ended March 31, 2022. During the three months ended March 31, 2022, the Company granted 362,280 restricted stock units (“RSUs”) under the 2021 Incentive Award Plan to certain employees and directors that vest ratably over a period of three years. The weighted average grant date fair value for the RSUs was $17.84. The Company also made a cash payment of $5.7 million to settle liability classified awards previously granted to the former CEO under the 2020 Plans during the three months ended March 31, 2022.

Supply Chain Financing

Supply Chain Financing	6 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Supply Chain Financing	Supply Chain Financing We have provided certain of our suppliers with access to a supply chain financing program through a third-party financing institution (the “SCF Bank”). This program allows us to seek extended payment terms with our suppliers and allows our suppliers to monetize their receivables prior to the payment due date, subject to a discount. Once a supplier elects to participate in the program and reaches an agreement with the SCF Bank, the supplier elects which individual invoices to sell to the SCF Bank. We then pay the SCF Bank on the invoice due date. We have no economic interest in a supplier’s decision to sell a receivable to the SCF Bank. The agreements between our suppliers and the SCF Bank are solely at their discretion and are negotiated directly between them. Our suppliers’ ability to continue using such agreements is primarily dependent upon the strength of our financial condition and guarantees issued by AES and Siemens. As of March 31, 2022, AES and Siemens issued guarantees of $50.0 million each, for a total of $100.0 million, to the SCF Bank on our behalf. As of March 31, 2022 and September 30, 2021, we had $52.1 million and $58.4 million of payables outstanding, respectively, subject to the program. All outstanding payments owed under the program are recorded within “Accounts payable” on the condensed consolidated balance sheets.

Subsequent Events

Subsequent Events	6 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Acquisition of Nispera AG In April 2022, Fluence acquired Nispera AG (“Nispera”), a Zurich-based provider of artificial intelligence (AI) and machine learning-enabled software-as-a-service (SaaS) targeting the renewable energy sector. The transaction included an all-cash buyout provision of approximately $30.0 million with respect to existing investors in Nispera, including members of Nispera’s management team, and the assumption of debt of approximately $2.6 million. In addition, Fluence issued 0.5 million shares of restricted stocks to Nispera’s management team that vest ratably over three years for retention purposes. 2022 Overheating Event at Customer Facility On April 18, 2022, a 10 MW energy storage facility in Chandler, Arizona owned by AES experienced an overheating event. Fluence served as the energy storage technology provider for the facility, which was completed in 2019, and Fluence currently provides maintenance services for the facility. There were no injuries. The facility has been taken offline as teams from Fluence, AES, and the battery manufacturer investigate the incident. We are currently not able to estimate the impact, if any, that this incident may have on our reputation or financial results, or on market adoption of our products.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Estimates (Policies)	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Accounting	The accompanying condensed consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and under the rules of the U.S. Securities and Exchange Commission (the “SEC”).
Consolidation	The accompanying condensed consolidated financial statements include the accounts of Fluence Energy Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Non-controlling Interest	The non-controlling interest on the condensed consolidated statements of operations and comprehensive loss represents the portion of earnings or loss attributable to the economic interest in Fluence Energy, LLC, held by the Founders. For the six months ended March 31, 2022, the net loss of Fluence Energy, LLC prior to the date of the Transactions has been attributed to the non-controlling interest, and the net loss of Fluence Energy, LLC subsequent to the date of the Transactions has been allocated between Fluence Energy, Inc. and the non-controlling interest based on the respective ownership percentages of Fluence Energy, LLC held by Fluence Energy, Inc. and the Founders. Non-controlling interest on the condensed consolidated balance sheets represents the portion of net assets of the Fluence Energy, LLC attributable to the Founders, based on the portion of the LLC Interests owned by such shareholders.
Reclassification	Certain prior year amounts have been reclassified from “Cost of goods and services” to “Sales and marketing” and “General and administrative” to conform to current period presentation on the condensed consolidated statements of operations and comprehensive loss.
Cash, Cash Equivalents, and Restricted Cash	Cash and cash equivalents include cash on-hand and highly liquid investments readily convertible to cash, with an original maturity of 90 days or less when purchased. Cash restricted for use as a result of financing or other obligations is classified separately as restricted cash on the Company’s condensed consolidated balance sheets.
Fair Value Measurements	The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs and to minimize the use of unobservable inputs. The following fair value hierarchy, defined by ASC 820, Fair Value Measurements , is used to classify assets and liabilities based on the observable inputs and unobservable inputs used to value the assets and liabilities: Level 1—Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2—Pricing inputs are other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 2 inputs include those financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted prices, time value, volatility factors, and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Level 3—Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value from the perspective of a market participant. The Company does not have significant recurring Level 3 fair value measurements. The Company’s cash equivalents include term deposits with original maturity of less than three months and are recorded at amortized cost. Fair value of cash equivalents approximates the carrying amount using Level 2 inputs. The carrying amounts of trade receivables, accounts payable and short-term debt obligations approximate fair values due to their short maturities using Level 2 inputs.
Loss per Share	Basic net loss per share of Class A common stock is computed by dividing net loss attributable to Class A common stockholders by the weighted average number of shares of Class A common stock outstanding during the period. Diluted net loss per share of Class A common stock is computed by adjusting the net loss available to Class A common stockholders and the weighted-average shares of Class A common stock outstanding to give effect to potentially dilutive securities. Shares of our Class B-1 and Class B-2 common stock are not entitled to receive any distributions or dividends and have no rights to convert into Class A common stock. When a common unit of Fluence Energy, LLC is exchanged for, at the Company’s election, cash or Class A common stock by a Founder who holds shares of our Class B-1 or Class B-2 common stock, such Founder will be required to surrender a share of Class B-1 or Class B-2 common stock, as the case may be, which we will cancel for no consideration. In the event of cash settlement, the Company is required to issue new shares of Class A common stock and use the proceeds from the sale of these newly-issued shares of Class A common stock to fully fund the cash settlement. Therefore, we did not include shares of our Class B-1 or Class B-2 common stock in the computation of basic loss per share. As we have incurred losses for all periods presented, diluted loss per share is equal to basic loss per share because the effect of potentially dilutive securities would be antidilutive. The potentially dilutive securities that were excluded consist of 117,173,390 Class B-1 common shares, 11,286,991 outstanding stock options, 2,167,290 outstanding phantom units, and 979,608 outstanding restricted stock units as of March 31, 2022.All earnings prior to and up to November 1, 2021, the date of completion of the IPO, were entirely allocable to non-controlling interest and, as a result, loss per share information is not applicable for reporting periods prior to this date. Consequently, only the net loss allocable to Fluence Energy, Inc. from the period subsequent to November 1, 2021 is included in the net loss attributable to the stockholders of Class A common stock for the six months ended March 31, 2022.
Recent Accounting Standards Adopted and Recent Accounting Standards Not Yet Adopted	Recent Accounting Standards Adopted No new accounting standards were adopted during the six months ended March 31, 2022. Recent Accounting Standards Not Yet Adopted The following table presents accounting standards not yet adopted: Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2016-02, Leases (Topic 842) In February 2016, the Financial Accounting Standard Board (“FASB”) issued ASU 2016-02, which supersedes existing guidance on accounting for leases in ASC 840, Leases . This standard requires all leases to be recognized on the consolidated balance sheet. FASB has issued several amendments to ASU 2016-02, including ASU 2018-11, Leases (Topic 842) : Targeted Improvements that introduced an additional transition method permitting an entity to initially apply the new lease standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ASU 2016-02 includes optional practical expedients intended to reduce the cost and complexity to implement the new lease standard, such as an option to maintain the current lease classification for all existing lease arrangements and the option to use hindsight in evaluating lessee options to extend or terminate a lease. Early application is permitted. As an emerging growth company (an “EGC”), the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2021. The Company’s existing lease population is mainly comprised of operating leases for office space. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2016-13, Financial Instruments—Credit Losses (Topic 326) In February 2016, FASB issued ASU 2016-13, which updates the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (“CECL”) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowance for losses. There are various transition methods available upon adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2019-12, Income Taxes (Topic 740) : Simplifying the Accounting for Income Taxes In December 2019, FASB issued ASU 2019-12, which removes certain exceptions related to the approach for intraperiod tax allocations, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. The guidance also clarifies and simplifies other areas of ASC 740. Certain amendments must be applied on a prospective basis, certain amendments must be applied on a retrospective basis, and certain amendments must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings/(deficit) in the period of adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting December 15, 2021, and for interim periods beginning after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting (Topic 848) In March 2020, FASB issued ASU 2020-04, which provides optional expedients and exceptions for applying U.S. GAAP to transactions affected by reference rate (e.g., LIBOR) reform if certain criteria are met, for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The ASU is effective as of March 12, 2020 through December 31, 2022. The Company is currently evaluating transactions or contract modifications occurring as a result of reference rate reform and determining whether to apply the optional guidance on an ongoing basis. The ASU is currently not expected to have a material impact on our consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Estimates (Tables)	6 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash as shown in the Company’s condensed consolidated statements of cash flows. in thousands March 31, 2022 March 31, 2021 Cash and cash equivalents $ 651,948 $ 29,883 Restricted cash 70,740 1,246 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 722,688 $ 31,129
Restrictions on Cash and Cash Equivalents	Restricted cash consisted of the following: in thousands March 31, 2022 March 31, 2021 Collateral for credit card program $ 1,422 $ 925 Collateral for outstanding bank guarantees 69,318 321 Total restricted cash $ 70,740 $ 1,246
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted net loss per share of Class A common stock for the three and six months ended March 31, 2022, respectively, have been computed as follows: In thousands, except share and per share amounts Three Months Ended March 31, 2022 Six Months Ended March 31, 2022 Net loss $ (60,704) $ (172,164) Less: Net loss attributable to the non-controlling interest (41,519) (124,174) Net loss attributable to Fluence Energy, Inc. $ (19,185) $ (47,990) Weighted average number of Class A common shares outstanding, basic and diluted 54,143,275 54,143,275 Loss per share of Class A common stock, basic and diluted $ (0.35) $ (0.89)
Accounting Standards Update and Change in Accounting Principle	The following table presents accounting standards not yet adopted: Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2016-02, Leases (Topic 842) In February 2016, the Financial Accounting Standard Board (“FASB”) issued ASU 2016-02, which supersedes existing guidance on accounting for leases in ASC 840, Leases . This standard requires all leases to be recognized on the consolidated balance sheet. FASB has issued several amendments to ASU 2016-02, including ASU 2018-11, Leases (Topic 842) : Targeted Improvements that introduced an additional transition method permitting an entity to initially apply the new lease standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ASU 2016-02 includes optional practical expedients intended to reduce the cost and complexity to implement the new lease standard, such as an option to maintain the current lease classification for all existing lease arrangements and the option to use hindsight in evaluating lessee options to extend or terminate a lease. Early application is permitted. As an emerging growth company (an “EGC”), the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2021. The Company’s existing lease population is mainly comprised of operating leases for office space. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2016-13, Financial Instruments—Credit Losses (Topic 326) In February 2016, FASB issued ASU 2016-13, which updates the impairment model for financial assets measured at amortized cost, known as the Current Expected Credit Loss (“CECL”) model. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowance for losses. There are various transition methods available upon adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. Standard Description Required date of adoption Effect on the financial statements and other significant matters ASU 2019-12, Income Taxes (Topic 740) : Simplifying the Accounting for Income Taxes In December 2019, FASB issued ASU 2019-12, which removes certain exceptions related to the approach for intraperiod tax allocations, the methodology for calculating income taxes in an interim period, and the recognition of deferred tax liabilities for outside basis differences. The guidance also clarifies and simplifies other areas of ASC 740. Certain amendments must be applied on a prospective basis, certain amendments must be applied on a retrospective basis, and certain amendments must be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings/(deficit) in the period of adoption. Early adoption is permitted. As an EGC, the Company is permitted to defer adoption until the non-public company adoption date, i.e., annual periods starting December 15, 2021, and for interim periods beginning after December 15, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. ASU 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting (Topic 848) In March 2020, FASB issued ASU 2020-04, which provides optional expedients and exceptions for applying U.S. GAAP to transactions affected by reference rate (e.g., LIBOR) reform if certain criteria are met, for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The ASU is effective as of March 12, 2020 through December 31, 2022. The Company is currently evaluating transactions or contract modifications occurring as a result of reference rate reform and determining whether to apply the optional guidance on an ongoing basis. The ASU is currently not expected to have a material impact on our consolidated financial statements.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue by Geographical Regions	The following table presents the Company’s revenue disaggregated by geographical region. Revenues are attributed to regions based on location of customers. In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Americas (North, Central and South America) $ 257,492 $ 67,965 $ 399,325 $ 112,117 APAC (Asia Pacific) 21,250 25,540 38,059 87,938 EMEA (Europe, Middle-East and Africa) 63,982 4,628 80,227 14,311 Total $ 342,724 $ 98,133 $ 517,611 $ 214,366
Change in Contract Liability	The following table provides information about deferred revenue from contracts with customers: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Deferred revenue beginning of period $ 145,765 $ 154,450 $ 71,365 $ 123,841 Additions 138,135 120,473 191,562 167,988 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (61,085) (66,022) (40,112) (82,928) Deferred revenue end of period $ 222,815 $ 208,901 $ 222,815 $ 208,901 In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Deferred revenue from related parties beginning of period $ 200,085 $ 44,281 $ 220,122 $ 11,425 Additions 120,097 70,903 153,078 103,831 Revenue recognized related to amounts that were included in beginning balance of deferred revenue (148,716) (3,105) (201,734) (3,177) Deferred revenue from related parties end of period $ 171,466 $ 112,079 $ 171,466 $ 112,079

Business Combinations (Tables)

Business Combinations (Tables)	6 Months Ended
	Mar. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the aggregate fair values and estimated useful lives of the assets acquired and liabilities assumed, as of the date of the acquisition. In thousands Fair Value Estimated Useful Life Intangible assets - Developed technology $ 12,600 12 years Intangible assets - Customer relationships 780 6 years Property and equipment 171 Various Goodwill 4,449 Cash paid for acquisition $ 18,000

Inventory, Net (Tables)

Inventory, Net (Tables)	6 Months Ended
	Mar. 31, 2022
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventory consisted of the following: In thousands March 31, 2022 September 30, 2021 Cost Provision Net Cost Provision Net Cubes, batteries, and other equipment (a) $ 345,650 $ (31) $ 345,619 $ 402,157 $ (12,980) $ 389,177 Shipping containers and spare parts 7,493 (1,127) 6,366 1,857 (1,247) 610 Total $ 353,143 $ (1,158) $ 351,985 $ 404,014 $ (14,227) $ 389,787 (a) Provision at September 30, 2021 included a $13.0 million loss recognized during fiscal year 2021 for inventory damaged in transit related to the 2021 cargo loss incident. During the six months ended March 31, 2022, $13.0 million of inventory was written off against the provision. Refer to Note 12 - Commitments and Contingencies for a detailed discussion of the 2021 cargo loss incident.

Other Current Assets (Tables)

Other Current Assets (Tables)	6 Months Ended
	Mar. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Current Assets	Other current assets consisted of the following amounts: In thousands March 31, 2022 September 30, 2021 Taxes recoverable 26,574 14,049 Prepaid expenses 2,874 2,480 Advance payments 4,919 3,601 Receivable from insurance (a) 2,500 10,000 Deferred equity issuance costs — 7,103 Prepaid insurance 4,190 — Other 6,352 4,684 Total $ 47,409 $ 41,917 (a) Receivable from insurance represents insurance recoveries that are probable of collection related to the 2021 cargo loss incident. The Company collected $7.5 million receivable from insurance during the six months ended March 31, 2022. Refer to Note 12 - Commitments and Contingencies for a detailed discussion of the 2021 cargo loss incident.

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	6 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Intangible assets are stated at amortized cost and consist of the following: In thousands March 31, 2022 September 30, 2021 Cost Accumulated Amortization Net Cost Accumulated Amortization Net Patents and licenses $ 33,003 $ (10,444) $ 22,559 $ 32,982 $ (9,207) $ 23,775 Developed technology (a) 12,600 (1,575) 11,025 12,600 (1,050) 11,550 Other (a) 1,093 (238) 855 894 (162) 732 Total $ 46,696 $ (12,257) $ 34,439 $ 46,476 $ (10,419) $ 36,057 (a) The developed technology intangible assets and other intangible assets included $12.6 million and $0.8 million, respectively, related to the business acquisition discussed in Note 4 - Business Combinations.

Goodwill (Tables)

Goodwill (Tables)	6 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table presents the goodwill activity: In thousands Six Months Ended March 31, 2022 2021 Goodwill, Beginning of the period $ 9,176 $ 4,731 Foreign currency adjustment (8) 19 Acquisition related goodwill (a) — 4,449 Goodwill, End of the period $ 9,168 $ 9,199 (a) Refer to Note 4 - Business Combination for a further discussion of acquisition related goodwill.

Current Accruals and Provisio_2

Current Accruals and Provisions (Tables)	6 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Schedule of Current Accruals and Provisions	Current accruals and provisions consisted of the following: In thousands March 31, 2022 September 30, 2021 Accruals $ 193,262 $ 155,963 Provisions for expected project losses 23,863 30,180 Total $ 217,125 $ 186,143

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	6 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following table presents the components of receivables from related parties and payables to related parties on the Company’s condensed consolidated balance sheets: In thousands March 31, 2022 September 30, 2021 Accounts receivable $ 4,732 $ 26,292 Unbilled receivables 32,302 7,070 Total receivables from related parties $ 37,034 $ 33,362 Accounts payable $ 881 $ 4,510 Deferred revenue 171,466 220,122 Accrued liabilities 4,326 3,293 Total payables and deferred revenue with related parties $ 176,673 $ 227,925 The following table presents the related party transactions that are included the Company’s condensed consolidated statements of operations and comprehensive loss for the periods indicated: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Revenue $ 226,926 $ 30,247 $ 374,759 $ 48,652 Cost of goods and services (2,301) (8,059) (9,796) (8,486) Research and development expenses — (80) (45) (172) Sales and marketing expenses (468) (326) (1,075) (662) General and administrative expenses (171) (185) (1,362) (367)

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Schedule of Stock Based Compensation Expense	The following table presents stock-based compensation expense by financial statement line item: In thousands Three Months Ended March 31, Six Months Ended March 31, 2022 2021 2022 2021 Cost of goods and services $ 749 $ — $ 4,277 $ — Research and development 1,524 — 3,337 — Sales and marketing (a) (1,987) — 4,454 — General and administrative 2,442 — 15,537 — Total $ 2,728 $ — $ 27,605 $ — (a) The reduction of stock based compensation expense for the three months ended March 31, 2022 was a result of the market-to-market adjustment of our liability classified awards which is driven by our stock price decrease during the three months ended March 31, 2022.

Organization and Operations (De

Organization and Operations (Details) $ / shares in Units, $ in Thousands	Nov. 01, 2021USD ($)$ / sharesshares	Dec. 27, 2020USD ($)shares	Mar. 31, 2022segment$ / shares
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of operating segments | segment			1
Number of reportable segments | segment			1
Class A common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Par value, Class A common stock (in usd per share) | $ / shares	$ 0.00001		$ 0.00001
Class B-1 common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Par value, Class A common stock (in usd per share) | $ / shares			$ 0.00001
IPO | Class A common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Shares sold in offering (in shares)	35,650,000
Public offering price per share (in usd per share) | $ / shares	$ 28
Aggregate net proceeds from stock offering | $	$ 935,800
Over-Allotment Option | Class A common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Shares sold in offering (in shares)	4,650,000
Fluence Energy, LLC
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned (in shares)	54,143,275
Fluence Energy, LLC percentage owned	31.60%		31.60%
Founders percentage owned	68.40%		68.40%
Fluence Energy, LLC | Founders
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned (in shares)	117,173,390
Fluence Energy, Inc | Founders | Class B-1 common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned (in shares)	117,173,390
Fluence Energy, Inc | Third Party Investor
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned percentage	65.80%
Fluence Energy, Inc | Third Party Investor | Class A common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned (in shares)	35,650,000
Fluence Energy, Inc | Qatar Holding LLC
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned percentage	34.20%
Fluence Energy, Inc | Qatar Holding LLC | Class A common stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment owned (in shares)	18,493,275
QIA Florence Holdings LLC (QFH)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Investment amount | $		$ 125,000
Class B units issued (in shares)		18,493,275

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Estimates - Non-controlling Interest (Details) - Fluence Energy, LLC	Mar. 31, 2022	Nov. 01, 2021
Noncontrolling Interest [Line Items]
Fluence Energy, LLC percentage owned	31.60%	31.60%
Founders percentage owned	68.40%	68.40%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies and Estimates - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 651,948	$ 36,829	$ 29,883
Restricted cash	70,740	1,240	1,246
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	$ 722,688	$ 38,069	$ 31,129	$ 95,051

Summary of Significant Accoun_6

Summary of Significant Accounting Policies and Estimates - Cash Restrictions (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 70,740	$ 1,240	$ 1,246
Credit Card Program Collateral
Cash and Cash Equivalents [Line Items]
Restricted cash	1,422		925
Outstanding Bank Guarantee Collateral
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 69,318		$ 321

Summary of Significant Accoun_7

Summary of Significant Accounting Policies and Estimates - Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Oct. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2022	Mar. 31, 2021
Loss per Share [Abstract]
Net loss	$ (20,317)	$ (60,704)	$ (23,532)	$ (151,847)	$ (172,164)	$ (36,028)
Less: Net loss attributable to the non-controlling interest		(41,519)	$ (23,532)		(124,174)	$ (36,028)
Net loss attributable to Fluence Energy, Inc.		$ (19,185)			$ (47,990)
Weighted average number of Class A common shares outstanding, basic (in shares)		54,143,275			54,143,275
Weighted average number of Class A common shares outstanding, diluted (in shares)		54,143,275			54,143,275
Loss per share of Class A common stock, basic (in usd per share)		$ (0.35)			$ (0.89)
Loss per share of Class A common stock, diluted (in usd per share)		$ (0.35)			$ (0.89)
Common Class B-1
Share-based Payment Arrangement [Abstract]
Antidilutive security					117,173,390
Stock options
Share-based Payment Arrangement [Abstract]
Antidilutive security					11,286,991
Phantom Share Units (PSUs)
Share-based Payment Arrangement [Abstract]
Antidilutive security					2,167,290
Restricted Stock Units (RSUs)
Share-based Payment Arrangement [Abstract]
Antidilutive security					979,608

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Geographical Regions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 342,724	$ 98,133	$ 517,611	$ 214,366
Americas (North, Central and South America)
Disaggregation of Revenue [Line Items]
Total revenue	257,492	67,965	399,325	112,117
APAC (Asia Pacific)
Disaggregation of Revenue [Line Items]
Total revenue	21,250	25,540	38,059	87,938
EMEA (Europe, Middle-East and Africa)
Disaggregation of Revenue [Line Items]
Total revenue	$ 63,982	$ 4,628	$ 80,227	$ 14,311

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Consolidated Entities, Excluding Affiliated Entities
Contract With Customer, Liability [Roll Forward]
Deferred revenue beginning of period	$ 145,765	$ 154,450	$ 71,365	$ 123,841
Additions	138,135	120,473	191,562	167,988
Revenue recognized related to amounts that were included in beginning balance of deferred revenue	(61,085)	(66,022)	(40,112)	(82,928)
Deferred revenue end of period	222,815	208,901	222,815	208,901
Affiliated Entity
Contract With Customer, Liability [Roll Forward]
Deferred revenue beginning of period	200,085	44,281	220,122	11,425
Additions	120,097	70,903	153,078	103,831
Revenue recognized related to amounts that were included in beginning balance of deferred revenue	(148,716)	(3,105)	(201,734)	(3,177)
Deferred revenue end of period	$ 171,466	$ 112,079	$ 171,466	$ 112,079

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Amount of remaining performance obligations	$ 2,150.1
Change in estimate of transaction price	$ 52.1		$ 52.8
Total Revenues | Customer Concentration Risk | One Customer
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total revenue percentage	70.00%
Total Revenues | Customer Concentration Risk | Two Customers
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total revenue percentage		77.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percentage of remaining performance obligations	91.00%
Expected time period of satisfaction (in yeaers)	5 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected time period of satisfaction (in yeaers)	5 years

Business Combinations - Narrati

Business Combinations - Narrative (Details) $ in Millions	1 Months Ended
	Oct. 31, 2020USD ($)
US Based Software and Digital Intelligence Platform
Business Acquisition [Line Items]
Cash paid for investment	$ 18

Business Combinations - Assets

Business Combinations - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2020	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Goodwill		$ 9,168	$ 9,176	$ 9,199	$ 4,731
US Based Software and Digital Intelligence Platform
Business Acquisition [Line Items]
Property and equipment	$ 171
Goodwill	4,449
Cash paid for acquisition	18,000
Developed technology | US Based Software and Digital Intelligence Platform
Business Acquisition [Line Items]
Intangible assets	$ 12,600
Estimated Useful Life	12 years
Customer Relationships | US Based Software and Digital Intelligence Platform
Business Acquisition [Line Items]
Intangible assets	$ 780
Estimated Useful Life	6 years

Inventory, Net (Details)

Inventory, Net (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Inventory [Line Items]
Cost	$ 353,143	$ 404,014
Provision	(1,158)	(14,227)
Net	351,985	389,787
Inventory valuation reserves, inventory write-down	13,000
2021 Cargo Loss Incident
Inventory [Line Items]
Provision		(13,000)
Cubes, batteries, and other equipment
Inventory [Line Items]
Cost	345,650	402,157
Provision	(31)	(12,980)
Net	345,619	389,177
Cubes, batteries, and other equipment | 2021 Cargo Loss Incident
Inventory [Line Items]
Provision		(13,000)
Shipping containers and spare parts
Inventory [Line Items]
Cost	7,493	1,857
Provision	(1,127)	(1,247)
Net	$ 6,366	$ 610

Other Current Assets (Details)

Other Current Assets (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Oct. 31, 2021	Mar. 31, 2022	Sep. 30, 2021
Offsetting Assets [Line Items]
Taxes recoverable		$ 26,574	$ 14,049
Prepaid expenses		2,874	2,480
Advance payments		4,919	3,601
Receivable from insurance		2,500	10,000
Deferred equity issuance costs		0	7,103
Prepaid insurance		4,190	0
Other		6,352	4,684
Total		47,409	$ 41,917
2021 Cargo Loss Incident
Offsetting Assets [Line Items]
Insurance proceed collected	$ 7,500	$ 7,500

Intangible Assets, Net (Details

Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Finite-Lived Intangible Assets [Line Items]
Cost	$ 46,696		$ 46,696		$ 46,476
Accumulated Amortization	(12,257)		(12,257)		(10,419)
Net	34,439		34,439		36,057
Amortization expense	900	$ 900	1,800	$ 1,700
Patents and licenses
Finite-Lived Intangible Assets [Line Items]
Cost	33,003		33,003		32,982
Accumulated Amortization	(10,444)		(10,444)		(9,207)
Net	22,559		22,559		23,775
Developed technology
Finite-Lived Intangible Assets [Line Items]
Cost	12,600		12,600		12,600
Accumulated Amortization	(1,575)		(1,575)		(1,050)
Net	11,025		11,025		11,550
Developed technology | US Based Software and Digital Intelligence Platform
Finite-Lived Intangible Assets [Line Items]
Net	12,600		12,600		12,600
Other
Finite-Lived Intangible Assets [Line Items]
Cost	1,093		1,093		894
Accumulated Amortization	(238)		(238)		(162)
Net	855		855		732
Other | US Based Software and Digital Intelligence Platform
Finite-Lived Intangible Assets [Line Items]
Net	$ 800		$ 800		$ 800

Goodwill - Narrative (Details)

Goodwill - Narrative (Details) - USD ($)	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of goodwill	$ 0	$ 0

Goodwill - Schedule of Goodwill

Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Goodwill [Roll Forward]
Goodwill, Beginning of the period	$ 9,176	$ 4,731
Foreign currency adjustment	(8)	19
Acquisition related goodwill	0	4,449
Goodwill, End of the period	$ 9,168	$ 9,199

Current Accruals and Provisio_3

Current Accruals and Provisions (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Payables and Accruals [Abstract]
Accruals	$ 193,262	$ 155,963
Provisions for expected project losses	23,863	30,180
Total	$ 217,125	$ 186,143

Short-term Debt - Revolving Cre

Short-term Debt - Revolving Credit Facility (Details) - The Revolver - Line of Credit - JP Morgan Chase Bank, N.A., Morgan Stanley Senior Funding, Inc., Bank of America, N.A., Barclays Bank PLC, and Five Other Banks	Nov. 01, 2021USD ($)bankqtr	Mar. 31, 2022USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowings		$ 0
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing amount	$ 190,000,000
Number of other banks in lenders party | bank	5
Commitment fee	0.55%
Minimum liquidity and gross revenue requirement of consolidated EBITDA	$ 150,000,000
EBITDA threshold period | qtr	4
Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Interest rate	3.00%
Revolving Credit Facility | Base Rate
Line of Credit Facility [Line Items]
Interest rate	2.00%
Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing amount	$ 190,000,000
Letter of credit participation fee	2.75%

Short-term Debt - Line of Credi

Short-term Debt - Line of Credit (Details) - USD ($)	Nov. 01, 2021	Mar. 31, 2022	Mar. 31, 2021	Oct. 31, 2021	Sep. 30, 2021
Line of Credit Facility [Line Items]
Repayment to line of credit		$ 50,000,000	$ 0
Citibank, N.A. | Line of Credit | Uncommitted Line Of Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing amount				$ 50,000,000
Outstanding borrowings					$ 50,000,000
Weighted average annual interest rate					2.83%
Repayment to line of credit	$ 50,000,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income tax expense	$ 128,000	$ 509,000	$ 486,000	$ 1,194,000
Effective tax rate	(0.20%)	(2.20%)	(0.30%)	(3.40%)
Unrecognized tax benefits	$ 0		$ 0		$ 0

Commitment and Contingencies (D

Commitment and Contingencies (Details) - USD ($)	1 Months Ended		6 Months Ended
	Apr. 30, 2022	Oct. 31, 2021	Mar. 31, 2022	Sep. 30, 2021	Apr. 28, 2021
Loss Contingencies [Line Items]
Advances to suppliers			$ 49,270,000	$ 9,741,000
Advances to suppliers			26,250,000	0
Inventory valuation reserves			1,158,000	14,227,000
Inventory valuation reserves, inventory write-down			13,000,000
Inventory capacity guarantee
Loss Contingencies [Line Items]
Advance payment			60,000,000
Advances to suppliers			33,700,000
Advances to suppliers			26,300,000
2021 Cargo Loss Incident
Loss Contingencies [Line Items]
Inventory valuation reserves				$ 13,000,000
Insurance proceeds expected					$ 10,000,000
Insurance proceed collected		$ 7,500,000	7,500,000
2021 Cargo Loss Incident | Subsequent Event
Loss Contingencies [Line Items]
Insurance proceed collected	$ 2,500,000
Minimum
Loss Contingencies [Line Items]
Potential losses related to reasonably possible material contingencies			0
Maximum
Loss Contingencies [Line Items]
Potential losses related to reasonably possible material contingencies			$ 5,000,000

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	Aug. 11, 2021	Mar. 31, 2022	Sep. 30, 2021
Related Party Transaction [Line Items]
Borrowing from related parties		$ 0	$ 50,000
Provision for receivables from related parties		$ 0	$ 0
Common Class B-1
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)		117,173,390
Affiliated Entity | AES Grid Stability
Related Party Transaction [Line Items]
Borrowing from related parties	$ 25,000
Subordinated promissory note, annual interest percentage	2.86%
Affiliated Entity | AES Grid Stability | Common Class B-1
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)		58,586,695
Affiliated Entity | Siemens Industry
Related Party Transaction [Line Items]
Borrowing from related parties	$ 25,000
Subordinated promissory note, annual interest percentage	2.86%
Affiliated Entity | Siemens Industry | Common Class B-1
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)		58,586,695

Related-Party Transactions - Ba

Related-Party Transactions - Balance Sheet Information (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Related Party Transactions [Abstract]
Accounts receivable	$ 4,732	$ 26,292
Unbilled receivables	32,302	7,070
Total receivables from related parties	37,034	33,362
Accounts payable	881	4,510
Deferred revenue	171,466	220,122
Accrued liabilities	4,326	3,293
Total payables and deferred revenue with related parties	$ 176,673	$ 227,925

Related-Party Transactions - St

Related-Party Transactions - Statement of Operations and Comprehensive Loss Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Related Party Transactions [Abstract]
Revenue	$ 226,926	$ 30,247	$ 374,759	$ 48,652
Cost of goods and services	(2,301)	(8,059)	(9,796)	(8,486)
Research and development expenses	0	(80)	(45)	(172)
Sales and marketing expenses	(468)	(326)	(1,075)	(662)
General and administrative expenses	$ (171)	$ (185)	$ (1,362)	$ (367)

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2,728,000	$ 0	$ 27,605,000	$ 0
Cash settled for stock based compensation			5,731,000	$ 0
2020 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash settled for stock based compensation			$ 5,700,000
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense					$ 0
Phantom Share Units (PSUs) | Executive Officer | 6 month anniversary of IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.33%
Phantom Share Units (PSUs) | Executive Officer | 18 month anniversary of IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.33%
Phantom Share Units (PSUs) | Executive Officer | 30 month anniversary of IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.33%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	362,280
RSU vesting period (in years)	3 years
Granted, Weighted average grant date fair value (usd per share)	$ 17.84
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense					$ 0

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2,728	$ 0	$ 27,605	$ 0
Cost of goods and services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	749	0	4,277	0
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	1,524	0	3,337	0
Sales and marketing (a)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	(1,987)	0	4,454	0
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 2,442	$ 0	$ 15,537	$ 0

Supply Chain Financing (Details

Supply Chain Financing (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Related Party Transaction [Line Items]
Guarantees issued	$ 100
AES Grid Stability | Affiliated Entity
Related Party Transaction [Line Items]
Guarantees issued	50
Siemens Industry | Affiliated Entity
Related Party Transaction [Line Items]
Guarantees issued	50
Supply Chain Financing Bank
Related Party Transaction [Line Items]
Payables outstanding subject to the program	$ 52.1	$ 58.4

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - Nispera shares in Millions, $ in Millions	1 Months Ended
	Apr. 30, 2022USD ($)shares
Asset Acquisition [Line Items]
Investment amount	$ 30
Assumption of debt	$ 2.6
Restricted Stock Units (RSUs)
Asset Acquisition [Line Items]
Entity interest issued (in shares) | shares	0.5
Restricted Stock Units (RSUs)
Asset Acquisition [Line Items]
Service requirement (in years)	3 years

Uncategorized Items - flnc-2022

Label	Element	Value
Noncontrolling Interest [Member]
Other Comprehensive Income (Loss), Net of Tax	us-gaap_OtherComprehensiveIncomeLossNetOfTax	$ 71,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	(20,317,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	(103,857,000)
AOCI Attributable to Parent [Member]
Other Comprehensive Income (Loss), Net of Tax	us-gaap_OtherComprehensiveIncomeLossNetOfTax	33,000
Other Comprehensive Income (Loss), Net of Tax	us-gaap_OtherComprehensiveIncomeLossNetOfTax	175,000
Retained Earnings [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	$ (47,990,000)