Seattle Startup Endurance Energy Achieves World's First Subsea Geothermal Power Milestone at Underwater Volcano

Endurance Energy, a Seattle-based startup founded in 2025 by former SpaceX engineer Andrew Redd, has announced the successful completion of the first end-to-end demonstration of subsea geothermal power generation. During a three-week deployment in September 2026 at Axial Seamount—an active underwater volcano roughly 300 miles off the Oregon coast and nearly a mile beneath the Pacific—the company drilled and completed what it claims is the world's first subsea geothermal well, deployed its 3-ton Adélie prototype power plant on the seafloor, and operated the system remotely from Seattle via subsea fiber-optic cable. While the test produced only 8.7 seconds of net-positive electricity (peaking at 16.5 kW net and averaging ~2 kW), with the turbine reaching 26,000 rpm, it marks a critical proof-of-concept for harnessing hydrothermal fluids from volcanic seafloor systems. The demonstration occurred after the drilled well (52 feet deep) provided insufficient flow, leading the team to connect to a natural vent at ~281°C (538°F). This aligns with broader efforts to develop next-generation geothermal technologies amid surging clean energy demand from AI data centers and electrification. Endurance plans a 2 MW commercial-scale project in Tonga by 2027, leveraging the compact design enabled by ocean pressure and cooling. The company has raised $63 million, including a $54 million Series A led by Founders Fund. Experts note challenges like higher costs compared to land-based geothermal, but highlight advantages for Pacific Ring of Fire nations facing expensive diesel imports. The rapid iteration pace draws from SpaceX methodologies, positioning subsea geothermal as a potential baseload complement to intermittent renewables.