v3.26.1
Cover
Sep. 08, 2026
Document Information [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Sep. 08, 2026
Entity File Number 001-40503
Entity Registrant Name NET POWER INC.
Entity Central Index Key 0001845437
Entity Tax Identification Number 98-1580612
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 11700 Katy Freeway
Entity Address, Address Line Two Suite 700
Entity Address, City or Town Houston
Entity Address, State or Province TX
Entity Address, Postal Zip Code 77079
City Area Code 888
Local Phone Number 323-6797
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false
Class A Common Stock, par value $0.0001 per share [Member]  
Document Information [Line Items]  
Title of 12(b) Security Class A Common Stock, par value $0.0001 per share
Trading Symbol NPWR
Security Exchange Name NYSE
Warrants, each exercisable for one share of Class A Common Stock at a price of $11.50 per share [Member]  
Document Information [Line Items]  
Title of 12(b) Security Warrants, each exercisable for one share of Class A Common Stock at a price of $11.50 per share
Trading Symbol NPWR-WT
Security Exchange Name NYSE