It is now proven that deep-sea volcanoes can generate clean electricity. Endurance Energy discovered this by putting a 3-ton power plant about a mile underwater on an active Pacific Ocean volcano and generating net-positive power.

During a three-week test at Axial Seamount, about 300 miles off the Oregon coast, the team drilled an offshore geothermal well, set up the plant on the seafloor, and controlled it live from Seattle. Hot water from a nearby hydrothermal vent ran through the system, spinning its turbine at 26,000 rpm. For 8.7 seconds, the system generated more electricity than it used, peaking at 16.5 kilowatts.

Representational image of the seafloor at the Axial Seamount, an active underwater volcano where a geothermal well will be drilled; Photo: USGS

“On Sept. 27, we put a power plant on an active underwater volcano and made power,” said Andrew Redd, founder and CEO of Endurance Energy and former SpaceX engineer. “This historic milestone is also our first end-to-end test.”

He added, “We now know, firsthand, what works at depth, what needs to be improved, and how to build the next system for sustained commercial generation.”

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The run ended when a battery shut down, and a broken pump cable stopped a restart attempt ten minutes later. However, the short run answered the team’s biggest question.

“The main question we had is, can the system generate more power than it uses?” said Redd. “Adélie did. Goddard’s first liquid-fueled rocket flew for two and a half seconds. Our first net-positive run lasted about nine. Our approach is to make it exist, then make it good.”

The Future of the Underwater Geothermal Well

The test site sat 5,000 feet deep in the Pacific Ocean. Endurance used seawater instead of chemical drilling mud and chose a site away from vent chimneys and marine life. Independent labs are currently analyzing water, rock, and mineral samples collected during the dive. Outside instruments showed no harm to local marine life, no strange seismic activity, and no shift in vent temperatures.

The test well reached 52 feet, but Endurance plans to drill down to 260 feet on its next attempt to get stronger fluid flow. This winter, the company will test an upgraded version of the system. Endurance is also building a 2-megawatt power generator and working on its first commercial project in the Kingdom of Tonga, aimed at supplying power by 2027 to replace imported diesel in the U.S. partner region.