Endurance has raised $54 million in Series A funding, led by Founders Fund, to develop subsea geothermal power systems. The Seattle startup aims to generate gigawatts of reliable, zero-emission electricity by drilling into hot underwater geothermal reservoirs and placing generators directly on the seafloor.
Endurance is proud to announce our $54M Series A, led by @foundersfund, to develop subsea geothermal energy. We’re building mass-manufacturable and mass-deployable generators to access terawatts of low cost, clean, baseload power. pic.twitter.com/KrZfybBaha
— Endurance Energy (@endurancegeo) June 11, 2026
The company says it has completed four deep-sea prototype deployments, reaching depths of up to 3,300 meters and temperatures of 386°C. Its next major step is Adelie, a 100-kilowatt system planned for deployment at the Juan de Fuca Ridge, combining drilling, power generation, and energy delivery in one unit.
Endurance believes offshore geothermal could provide dependable electricity for coastal regions, particularly as demand rises from AI data centers and industrial growth. The company plans to use its Seattle operations to rapidly develop and test the technology, with the goal of delivering geothermal power to the grid within the next two years.
