Endurance Energy raises $54M to tap geothermal power from undersea volcanoes

Endurance Energy Inc., a Seattle startup building generators that tap heat from undersea volcanoes, revealed today that it has raised $54 million in new funding to advance its plans for offshore power plants as energy demand surges.

Founded in 2024 by Andrew Redd, a former SpaceX engineer, Endurance is going after a geothermal source its rivals have mostly so far left alone: volcanoes on the seabed.

Geothermal developers drill thousands of feet down to find rock hot enough to run a plant and the best sites are mostly in remote areas, far from where the power is needed. Endurance is betting on the ocean. At certain points on the seafloor, tectonic plates split apart and magma heats the water to 728 degrees Fahrenheit. Those are the spots it plans to drill.

Redd, who worked on the Dragon and Starship programs at SpaceX, argues that pace of development sets the company apart. “Our SpaceX heritage enables a pace of development that is unprecedented for new energy projects,” he said in a LinkedIn post announcing the round.

Endurance has run four prototype deployments over the past year, sinking test devices to deep-sea volcanoes nearly 1,000 feet down. The first full system, a 100-kilowatt generator called Adelie, is set to go in later this year at the Juan de Fuca ridge off Washington and Oregon. The company describes Adelie as its first complete system, capable of drilling into the seafloor, generating electricity from the heat and handling the energy transfer back to shore.

The eventual goal is far larger. Endurance aims to produce power at gigawatt scale and is targeting delivery of electricity to the grid within two years. For comparison, Washington’s Grand Coulee Dam, the largest power station of any kind in the U.S., has a capacity of 6.8 gigawatts. Redd estimates roughly 6 terawatts could be developed around the Pacific “Ring of Fire” over the next five to 10 years.

“The idea is that you could support any major coastal city on the Ring of Fire,” Redd told TechCrunch.

The funding comes as geothermal draws fresh investor interest on the promise of around-the-clock, carbon-free power for data centers, electric vehicles and heavy industry. Fervo Energy Co. raised $462 million in December, with Google LLC among its backers. Sage Geosystems Inc. closed a round worth more than $97 million in January. Geothermal still accounts for only 0.4% of U.S. power generation.

The Series A was led by Founders Fund. New backers Felicis, Voyager Ventures, Riot Ventures and Construct Capital joined, along with returning investors Point72 Ventures, First Round Capital and Ascend.

Image: Endurance Energy