NET Power Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

For the fiscal year ended December 31, 2025

OR

For the transition period from ____________ to ____________

Commission file number 001-40503

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code:(919) 287-4750

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yeso No x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yeso No x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x Noo

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes x Noo

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. o

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. o

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yeso Nox

The aggregate market value of the registrant’s voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2025 was approximately $73.8 million (computed by reference to the last per share sale price of the Class A Common Stock on the New York Stock Exchange of$2.47 on such date).

The registrant had outstanding 84,687,931 shares of Class A Common Stock and 139,727,880 shares of Class B Common Stock as of March 5, 2026.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the definitive Proxy Statement for the registrant’s 2026 Annual Meeting of Stockholders have been incorporated by reference into Part III of this Report.

TABLE OF CONTENTS

Certain Defined Terms

Unless otherwise expressly stated or, unless the context otherwise requires, references in this Annual Report on Form 10-K (this “Report”) to:

•“8 Rivers” means 8 Rivers Capital, LLC, a Delaware limited liability company (a company controlled by SK Energy);

•“Amended and Restated JDA” means the Amended and Restated Joint Development Agreement, dated December 13, 2022, by and among Old NET Power, RONI, RONI OpCo, NPI, and NPT, as amended, supplemented or otherwise modified from time to time in accordance with its terms;

•“Amine-based solvent” means Entropy’s proprietary solvent, Entropy23™, used to separate carbon dioxide from other industrial emissions in the post-combustion capture cycle;

•“Baker Hughes” or “BH” means Baker Hughes Company, a Delaware corporation;

•“BHES” means Baker Hughes Energy Services LLC, a Delaware limited liability company and affiliate of Baker Hughes;

•“BHES JDA” means collectively, the Original JDA and the Amended and Restated JDA;

•“BHES JDA Make-Whole Payment” means the incremental payment required if the volume-weighted average price of the Company’s stock for ten consecutive trading days (“10-Day VWAP”) immediately preceding the payment date for services under the BHES JDA is less than $4.00 per share (the “Floor Price”), an incremental cash payment is required for the difference between the 10-Day VWAP and the Floor Price;

•“Board” or “Board of Directors” means the board of directors of the Company;

•“Business Combination Agreement” means the Business Combination Agreement, dated as of December 13, 2022, by and among RONI, RONI OpCo, Buyer, Merger Sub and Old NET Power, as amended by the First Amendment to the Business Combination Agreement, dated as of April 23, 2023, by and between Buyer and Old NET Power;

•“Business Combination” means the Merger and other transactions contemplated by the Business Combination Agreement, collectively;

•“Buyer” means Topo Buyer Co, LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of OpCo;

•“Class A Common Stock” means the Class A common stock, par value $0.0001 per share, of NET Power;

•“Class B Common Stock” means the Class B common stock, par value $0.0001 per share, of NET Power;

•“Common Stock” means the Class A Common Stock and Class B Common Stock;

•“Company,” “our,” “we” or “us” means, prior to the Business Combination, RONI or Old NET Power, as the context suggests, and, following the Business Combination, NET Power Inc., in each case, with its consolidated subsidiaries;

•“Constellation” means Constellation Energy Generation, LLC, a Pennsylvania limited liability company formerly known as Exelon Generation Company, LLC;

•“DOE” means the United States Department of Energy;

•“Entropy” or “Entropy Inc.” means Entropy Inc., a Calgary-based PCC technology developer;

•“Exchange Act” means the Securities Exchange Act of 1934, as amended;

•“IPO” means RONI’s initial public offering, which was consummated on June 18, 2021;

•“La Porte Demonstration Facility” means the test facility located in La Porte, Texas used to demonstrate the viability of Net Power’s Oxy-Combustion Cycle technology;

•“Legacy NET Power Holders” means the holders of equity securities of Old NET Power prior to the consummation of the Merger;

•“Merger” means the merger of Merger Sub with and into Old NET Power pursuant to the Business Combination Agreement, in which Old NET Power survived and became a direct, wholly owned subsidiary of Buyer;

•“Merger Sub” means Topo Merger Sub, LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of Buyer;

•“Net Power” means NET Power Inc., a Delaware corporation (f/k/a Rice Acquisition Corp. II), with its consolidated subsidiaries (unless the context otherwise indicates);

•“NPI” means Nuovo Pignone International, S.r.l., an Italian limited liability company and affiliate of Baker Hughes;

•“NPT” means Nuovo Pignone Tecnologie S.r.l., an Italian limited liability company and affiliate of Baker Hughes;

•“NYSE” means the New York Stock Exchange;

•“Old NET Power” means, prior to the consummation of the Merger, NET Power, LLC, a Delaware limited liability company;

•“OpCo” means NET Power Operations LLC, a Delaware limited liability company (f/k/a Rice Acquisition Holdings II LLC);

•“OpCo LLC Agreement” means, (1) prior to January 17, 2025, the Second Amended and Restated Limited Liability Company Agreement of OpCo, dated as of June 8, 2023, which was entered into in connection with the Closing, and (2) beginning on January 17, 2025, the Third Amended and Restated Limited Liability Company Agreement of OpCo, dated as of January 17, 2025;

•“OpCo Unitholder” means a holder of OpCo Units;

•“OpCo Units” means the units of OpCo;

•“Original JDA” means the Joint Development Agreement, dated February 3, 2022, by and among Old NET Power, NPI, and NPT, as amended by the First Amendment to Joint Development Agreement, dated effective June 30, 2022, by and among the same parties;

•“OXY” means OLCV NET Power, LLC, a Delaware limited liability company;

•"Oxy-Combustion Cycle” refers to Net Power’s patented oxy-combustion and supercritical CO 2 power cycle that results in near-zero carbon dioxide emissions and eliminates criteria pollutants;

•“Post-combustion carbon capture” or “PCC” refers to Entropy’s proprietary modular carbon capture and storage (MCCS) solvent technology for post-combustion carbon capture. Net Power signed a letter of intent on November 7, 2025 to negotiate one or more definitive agreements under which Net Power would, among other things, exclusively license and commercialize Entropy’s PCC technology for power generation in the United States and to jointly develop projects;

•“Preferred Stock” means shares of NET Power preferred stock, par value $0.0001;

•“Principal Legacy NET Power Holders” means OXY, Constellation, and 8 Rivers (through NPEH);

•“Private Placement Warrants” means the 10,900,000 warrants to purchase shares of Class A Common Stock that were issued and sold to Sponsor in a private placement in connection with the IPO;

•“Public Warrants” means the warrants to purchase shares of Class A Common Stock that were issued and sold as part the units of RONI in the IPO;

•“RONI” means Rice Acquisition Corp. II, a Cayman Islands exempted company, prior to the Business Combination;

•“RONI OpCo” means Rice Acquisition Holdings II LLC, a Cayman Islands limited liability company and direct subsidiary of RONI, prior to the Business Combination;

•“SEC” means the U.S. Securities and Exchange Commission;

•“Securities Act” means the Securities Act of 1933, as amended;

•“Sponsor” means Rice Acquisition Sponsor II LLC, a Delaware limited liability company;

•“Tax Receivable Agreement” or “TRA” means the Tax Receivable Agreement, dated June 8, 2023, entered into by NET Power and OpCo with OpCo Unitholders who received OpCo Units pursuant to the Business Combination Agreement as consideration for equity interests in Old NET Power and the Agent (as defined therein);

•“Warrant Agreement” means the Warrant Agreement, dated as of June 15, 2021, by and among RONI, RONI OpCo, and Continental Stock Transfer & Trust Company as it may be amended and/or restated from time to time in accordance with its terms; and

•“Warrants” means, collectively, the Public Warrants and Private Placement Warrants.

In addition, the following is a glossary of key industry terms used herein:

•“CO 2” means carbon dioxide;

•“MW” means megawatt;

•“MWth” means megawatt thermal and refers to the input energy required;

•“NOX” means nitrogen oxides;

•“sCO 2” means supercritical carbon dioxide; and

•“SOX” means sulfur oxides.

Cautionary Note Regarding Forward-Looking Statements

This Report contains “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. Statements that do not relate strictly to historical or current facts are forward-looking and usually identified by the use of words such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” “future,” “intend,” “may,” “opportunity,” “plan,” “project,” “seek,” “should,” “strategy,” “will,” “will likely result,” “would” and other similar words and expressions, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements may relate to the development of the Company’s technology, the anticipated demand for the Company’s technology and the markets in which the Company operates, the timing of the deployment of project deliveries, and the Company’s business strategies, capital requirements, potential growth opportunities and expectations for future performance (financial or otherwise). Forward-looking statements are based on current expectations, estimates, projections, targets, opinions and/or beliefs of the Company, and such statements involve known and unknown risks, uncertainties and other factors.

The risks and uncertainties that could cause those actual results to differ materially from those expressed or implied by these forward-looking statements include:

•risks relating to the uncertainty of the projected financial information with respect to the Company and risks related to the Company’s ability to meet its projections;

•the Company’s ability to utilize its net operating loss and tax credit carryforwards effectively;

•the capital-intensive nature of the Company’s business model, which will likely require Net Power to raise additional capital in the future;

•the ability of the Company to effectively secure licenses for third-party PCC technology and to integrate such technology in its projects;

•barriers the Company may face in its attempts to deploy and commercialize its technology;

•the complexity of the machinery the Company relies on for its operations and development, including Entropy’s PCC technology;

•the Company’s ability to adequately control or accurately predict the costs associated with its projects;

•barriers that the Company may face in its attempts to deploy projects;

•the complexity of the machinery the Company relies on for its operations and development;

•potential changes and/or delays in site selection and construction that result from regulatory, logistical, and financing challenges;

•the Company’s ability to establish and maintain supply relationships;

•risks related to strategic investors and partners, including potential conflicts of interests between the Company and such investors and partners;

•the Company’s ability to successfully commercialize its operations;

•the lack of federal support of clean energy technology by the Trump administration;

•the availability and cost of technological components and raw materials for its projects;

•the impact of potential delays in discovering manufacturing and construction issues;

•the ability of Net Power’s commercial plants to efficiently provide net power output;

•the impact of public perception of fossil fuel-derived energy on the Company’s business;

•any political or other disruptions in gas producing nations;

•the Company’s ability to protect its intellectual property and the intellectual property it licenses;

•risks relating to data privacy and cybersecurity, including the potential for cyberattacks or security incidents that could disrupt our or our service providers’ operations;

•current and potential litigation that has been and may be instituted against the Company; and

•other risks and uncertainties indicated in Part I, Item 1A of this Annual Report and other documents subsequently filed with the SEC by the Company.

Should one or more of these risks or uncertainties materialize, or should any of the assumptions made by our management prove incorrect, actual results may vary in material respects from those projected in the forward-looking statements contained in this Report. Accordingly, you should not place undue reliance on these forward-looking statements in deciding whether to invest in our securities.

Forward-looking statements speak only as of the date they are made. Except to the extent required by applicable law or regulation, we undertake no obligation to update the forward-looking statements contained herein to reflect events or circumstances after the date of this Report or to reflect the occurrence of unanticipated events. The Company gives no assurance that it will achieve its expectations.

Summary Risk Factors

Our business is subject to numerous risks and uncertainties, including those highlighted in Item 1A, “Risk Factors,” that represent challenges that we face in connection with the successful implementation of our strategy and the growth of our business. In particular, the following risks, among others, may offset our competitive strengths or have a negative effect on our business strategy:

•We have incurred significant losses since inception, and we anticipate that we will continue to incur losses in the future, and we may not be able to achieve or maintain profitability.

•We may be unable to manage our future growth effectively.

•We face significant barriers in our attempts to deploy our power plants and we may not be able to successfully develop our power plants.

•We may be unable to successfully negotiate and enter into a definitive agreement with Entropy to exclusively license its PCC technology.

•We intend to rely on the licensing of PCC technology from Entropy in order to integrate such technology into our power plants.

•We may be unable to successfully develop a modular, standardized clean gas power plant product incorporating Entropy’s PCC technology (the “Clean Gas Product”).

•The power plants we are developing will rely on complex machinery for their operation and deployment involves a significant degree of risk and uncertainty in terms of operational performance and costs.

•We and our partners may be unable to adequately control or accurately predict the costs associated with constructing our first commercial-scale facility and the development and deployment of additional power plants.

•Our projects will require significant capital expenditures for which financing will be necessary. Such financing might not be obtainable on terms or on timeline that are favorable to us.

•We, our partners, or our third-party suppliers may experience delays in the development and manufacturing of key equipment.

•We and our partners may not be able to establish supply relationships for necessary components or may be required to pay costs for components that are higher than anticipated.

•Our deployment plans rely on the development and supply of post-combustion carbon capture equipment by Entropy.

•Our commercialization strategy relies heavily on our relationships with Entropy, Baker Hughes, OXY, Constellation, and other strategic investors and partners, who may have interests that diverge from ours and who may not be easily replaced if our relationships are not maintained.

•Manufacturing and transportation of key equipment may be dependent on global supply chains.

•Manufacturing and construction issues not identified prior to design finalization, long-lead procurement, and/or module fabrication could potentially be realized during production, fabrication, or construction and may impact plant deployment cost and schedule.

•Conflicts of interest may arise because several directors on the Board are designated by certain of our largest stockholders.

•The energy market continues to evolve and is highly competitive. The development and adoption of competing technology could materially and adversely affect our ability to develop our power plants.

•The market for power plants implementing carbon capture technologies is not yet established and there is limited infrastructure to efficiently transport and store carbon dioxide. The market may not achieve the growth potential we expect and may grow more slowly than we expect.

•The cost of electricity generated fromour power plants may not be cost competitive with other electricity generation sources in some markets.

•Our business relies on the deployment of power plants that are subject to a wide variety of extensive and evolving government laws and regulations, including environmental laws and regulations.

•We may encounter substantial delays in the design, manufacture, regulatory approval, and launch of power plants. Regulatory approvals and permits may also be denied.

•A number of governmental agencies, including the Department of Energy and the Environmental Protection Agency, have de-emphasized the significance of clean energy technology and the impact of greenhouse gas emissions on climate change, which may directly impact our potential customers’ desire to procure the energy supplied by our power plants and the associated environmental attributes.

•We and our customers operate in a politically sensitive environment, and the public perception of fossil fuel derived energy can affect our customers and us. Our future growth and success are dependent upon consumers’ willingness to develop natural-gas-fueled power generation facilities.

•The ability to deploy natural gas power plants may be limited due to conflict, war or other political disagreements between gas-producing nations and potential customers, and such disagreements may adversely impact our business plan.

•The information technology systems and data that we maintain may be subject to intentional or inadvertent disruption or other security incidents that could result in regulatory investigations or actions, litigation, fines and penalties, disruptions of our business operations, reputational harm, and other adverse business consequences.

•We are a holding company and our organizational structure confers certain benefits upon the holders of shares of Class B Common Stock and OpCo Units that will not benefit the holders of shares of Class A Common Stock to the same extent.