Net Power Inc.

For the definitions of certain defined terms used throughout this Quarterly Report on Form 10-Q (this “Report”), please refer to the section entitled “Certain Defined Terms” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “Annual Report”).Capitalized terms used but not otherwise defined in this Report have the meanings assigned to them in the Annual Report. In addition, the following terms are used in this Report:

•“Entropy PCC Technology” means the proprietary solvent-based post-combustion carbon capture technology of Entropy Inc., which Entropy markets as its modular carbon capture and storage solution. On November 7, 2025, the Company and Entropy entered into a letter of intent, non-binding except for certain customary provisions, contemplating the negotiation of one or more definitive agreements under which the Company and Entropy would have jointly developed an application of Entropy PCC Technology for use in combined cycle gas turbine power plants, deployed Entropy PCC Technology on an exclusive basis for power generation applications in the United States, and jointly developed projects utilizing such developed technology. That letter of intent has expired by its terms and has not been replaced. The Company has not entered into a definitive agreement for the license of PCC technology, and either party may discontinue negotiations at any time. See Part I, Item 2, Management’s Discussion and Analysis of Financial Condition and Results of Operations.

•“Post-combustion carbon capture” or “PCC” means the capture of carbon dioxide from the flue gas of a combustion process, including through the use of chemical solvents.