Endurance generates net power from subsea geothermal for 8.7 seconds

Endurance Energy announced on October 19, 2026 that its three-ton Adélie unit generated net positive electricity from a subsea geothermal system at nearly 1,500 meters depth at Axial Seamount, an active volcano off the coast of Oregon. Net generation lasted 8.7 seconds, with a peak of 16.5 kilowatts and a median output of about 2 kW, according to Ars Technica.

The test took place on September 27 during a three-week expedition aboard the vessel Ocean Guardian, some 300 miles west of Oregon, near the Juan de Fuca Ridge. According to Canary Media, the turbine produced about 60 watt-hours in nearly half a minute; for almost 9 of those seconds it generated more than it consumed. The run was cut short when a battery protection system shut down the plant and, on restart, a cable feeding the coolant pump failed due to a crack that let seawater in.

For the region, the data matters because next-generation geothermal is presented as a baseload source, available continuously, that complements solar and wind. The Seattle-based firm, founded in January 2025 by Andrew Redd, a former SpaceX engineer, has raised 63 million dollars, including a 54 million Series A led by Founders Fund, according to ThinkGeoEnergy.

The Adélie system, rated at 100 kW, occupies a space comparable to an automobile and uses an organic Rankine cycle, the same principle behind many onshore geothermal plants. It was not tested with the drilled 16-meter well, whose fluids reach about 260 degrees Celsius: its flow rate proved insufficient. The unit was connected to a natural vent of approximately 281 degrees and the turbine reached about 26,000 revolutions per minute. The operation was controlled remotely from Seattle via the subsea fiber-optic network of the U.S. National Science Foundation (NSF).

Endurance is already preparing Gentoo, an improved version of Adélie, with a test planned for the winter of 2026-2027 aimed at sustaining higher power. It is also developing a 2 MW commercial generator and plans up to six such units in Tonga, with the first commercial deployment in 2027. The point to watch is whether Gentoo sustains generation for minutes, not seconds.

This article was written with the assistance of artificial intelligence from verified sources and reviewed by a human editor before publication.