Subsea Geothermal Plant Hits 16.5 Kilowatt Peak Power
The Adélie system tests subsea power generation, producing net electricity before a mechanical cable failure.
Updated on Oct. 28, 2026 in Energy
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Endurance Energy has demonstrated a subsea geothermal power plant, the Adélie, which produced a peak of 16.5 kilowatts of net electricity. This research-stage test at the Axial Seamount lasted 8.7 seconds before a power cable failure occurred.
Why it matters
The test marks a move toward harvesting energy from deep-sea hydrothermal vents, a potential source of consistent power. This demonstration serves to validate that subsea systems can produce net-positive electricity, a critical step for future offshore infrastructure.
The Adélie system achieved a median net output of 2 kilowatts during its short-lived operation. While the plant features an installed capacity of 100 kilowatts, the test concluded prematurely due to a power cable failure.
The players
Endurance Energy
A startup founded in 2025 that develops subsea geothermal power extraction technologies.
The details
The Adélie system operates by drilling a 52-foot geothermal well near a natural hydrothermal vent, which reaches temperatures of 538 degrees Fahrenheit. The plant captures fluid flow from the vent, using the high-temperature gradient to drive power conversion before returning the fluid to the seafloor. This approach builds upon previous subsea drilling attempts, such as those conducted in Iceland in 2017.
Timeline
2016: Chinese researchers produce 4 watts of geothermal power.
2017: A geothermal project in Iceland performs subsea drilling.
January 2025: Endurance Energy is founded.
October 2026: Endurance Energy announces test results.
Winter 2026-27: Endurance Energy plans to test the Gentoo system.
The Tech Race
This demonstration advances subsea energy generation beyond the 4-watt milestone set by researchers in 2016. It follows earlier industry efforts, including subsea drilling in Iceland, as firms move toward commercial-scale seafloor power.
This technology remains in the research phase and does not currently impact national power grids or local utility pricing. If future trials succeed, Endurance Energy targets a commercial-scale project in the Kingdom of Tonga by 2027.
The takeaway
The test validates the feasibility of subsea geothermal energy generation, despite the short duration of the current demonstration. Investors should track the upcoming Gentoo system test in the winter of 2026-27 to see if the firm can maintain power output for longer periods.
What happens next
Endurance Energy is scheduled to conduct a field test of its upgraded Gentoo system during the winter of 2026-2027.
Further reading
Learn more about the latest innovations in Energy.
Source note: This article includes information reported by Gizmodo.
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