General and administrative expense. General and administrative expense increased $2.3 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023, primarily due to support efforts for carbon sequestration initiatives, increases in personnel costs related to the hiring of highly qualified and skilled professionals, and professional consulting fees, partially offset by a decrease in stock-based compensation. On an annual basis, we assess our corporate cost allocation estimates across all segments to reflect the use of centralized administrative functions as well as the allocation of personnel costs related to our project development efforts.
Project development costs. Project development costs are primarily related to our Net-Zero Projects and Verity, which consist primarily of employee expenses, preliminary engineering costs, and technical consulting costs. Project development costs increased $7.2 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023, primarily due to patent related costs, increases in personnel costs, and consulting fees.
Facility idling costs. Facility idling costs are related to the care and maintenance of our Luverne Facility. Facility idling costs decreased $0.2 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023.
Loss from operations. The Company’s loss from operations increased by $7.4 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023, primarily due to the increase in costs for our Net-Zero and Verity projects.
Interest expense. Interest expense increased $0.6 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023, and was primarily comprised of interest on the Remarketed Bonds.
Interest and investment income. Interest and investment income decreased $0.1 million during the six months ended June 30, 2024, compared to the six months ended June 30, 2023, primarily due to the usage of cash for our capital projects and operating costs, resulting in a lower balance of cash equivalent investments during the six months ended June 30, 2024.
Other income (expense), net. Other income (expense), net increased $0.2 million for the six months ended June 30, 2024, compared to the six months ended June 30, 2023, primarily due to the termination of an agreement at our idled Luverne Facility.
Critical Accounting Policies and Estimates
There have been no significant changes to our critical accounting estimates and policies since December 31, 2023. For a description of our other critical accounting policies and estimates that affect our significant judgments and estimates used in the preparation of our condensed consolidated financial statements, refer to “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Estimates” contained in our 2023 Annual Report.
Our unaudited condensed consolidated financial statements are prepared in conformity with GAAP and require our management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, costs and expenses and related disclosures. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. Actual results may differ from these estimates, and such estimates may change if the underlying conditions or assumptions change.
Liquidity and Capital Resources
As of June 30, 2024, we had cash and cash equivalents of $245.7 million and current and non-current restricted cash of $69.6 million. As of June 30, 2024, we had net working capital of $232.9 million, with $25.3 million of current liabilities. Our cash equivalents consist of investments in U.S. government money market funds. We expect to use our cash, cash equivalents, and restricted cash for the following purposes: (i) identification, development, engineering, licensing, acquisition and construction of production facilities and the Company’s Net-Zero Projects; (ii) potential investment in RNG projects; (iii) potential development of the Luverne Facility; (iv) operating activities at the Company’s corporate headquarters in Colorado, including research and development work; (v) exploration of strategic alternatives and additional financing, including project financing; and (vi) future debt service obligations. We believe as a result of our cash and cash equivalents balances, and the performance of our current and expected operations, we will be able to meet our obligations and other potential cash requirements during the next 12 months from the date of this report.