Underwater Volcano Powers Generator Past Break-Even for 8.7 Seconds

A Seattle company says a generator on the seafloor, driven by heat from an underwater volcano off Oregon, briefly made more electricity than it consumed. The surplus lasted 8.7 seconds, according to ScienceAlert, which reported on the company's results.

Endurance Energy announced the Adélie experiment in a press release on Oct. 19. The figures come from the company, and no peer-reviewed paper has reported them.

What exactly did the team test?

Engineers lowered a generator to Axial Seamount, a volcano about 480 kilometers (300 miles) off Oregon. Hot springs emerge there from the seabed roughly 1,500 meters (5,000 feet) below the surface. The aim was to see whether the system could produce more power than it needed to run its own pumps and other parts.

During the Sept. 27 test, the turbine reached about 26,000 revolutions per minute. The team operated the equipment from Seattle through an existing undersea cable network run by the University of Washington, called the Regional Cabled Array.

Where did the heat come from?

Seawater seeps into cracks in the seabed, is heated by molten rock below, and flows back out through hydrothermal vents. The engineers first drilled a well 16 meters (52 feet) into the seabed. Water from it reached about 260°C (500°F), but the flow was too weak to run the generator.

So Adélie was connected to a nearby natural vent instead. That water was approximately 281°C (538°F). Heavy pressure at that depth keeps it liquid well above the 100°C (212°F) boiling point at the surface.

How much power did it make?

After subtracting the electricity the system used, the company reported a median surplus of about 2 kilowatts over the 8.7 seconds, with a peak of 16.5 kilowatts. These figures cover only the generator's operation. They do not include energy spent on shipping, drilling and installation, ScienceAlert noted.

Seafloor vents have powered devices before. A Chinese team described one in a 2016 Applied Energy study. It ran on the temperature difference between vent water and cold seawater and produced 2.6–3.9 watts continuously, enough for a data logger and an LED lamp.

Why did the run end, and what comes next?

A safety system that protects the battery from excessive current shut Adélie down. About 10 minutes later, a pump power cable failed during a restart attempt.

Founder and CEO Andrew Redd told ScienceAlert that the next test generator, Gentoo, is an upgraded Adélie rated at 100kW. It is due to be deployed this winter, with the aim of higher power and longer runs. Redd said the changes will address the battery and cable problems.

Endurance also expects a new drill next year that can reach 500 meters at maximum, compared with the current drill's 80-meter (260-foot) limit. The company expects deeper wells to deliver more water flow. Redd said the team still has to show sustained generation from a drilled well and build equipment that works reliably for months or years.

Why does it matter, and what are the environmental questions?

Geothermal plants on land already use underground heat to make electricity without relying on sun or wind. Endurance wants to bring that approach to the seafloor. Its first commercial project is being developed in Tonga, a Pacific island nation whose grid relies largely on imported diesel, with first power targeted for 2027. For now, the result shows that the concept can work for a few seconds, not that it can supply a grid.

Vent ecosystems add another open question. Microbes there use chemicals for energy, and tubeworms and other animals depend on those microbes. Endurance says it chose a drilling site away from vent chimneys and nearby animals, and that its monitoring found no notable change in life around the site. It also said more than 40 water, rock and mineral samples went to independent laboratories.

Redd acknowledged that larger systems running continuously for years could affect the surrounding water, biological communities and seafloor habitat. He said the company is working with independent researchers on further studies. Longer-term effects remain to be established, according to ScienceAlert.

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Around Prague, based on reporting by ScienceAlert