A startup drilled into an underwater volcano for electricity

Seattle startup Endurance Energy parked a generator on the seafloor next to an active underwater volcano, about 5,000 feet down, and got it to make more electricity than it used for about 8.7 seconds. Ars Technica calls it the world’s first demonstration of a subsea geothermal power plant. Founder Andrew Redd told Ars that no one had done that before.

The setup reads like a sci-fi parts list. A drill lowered from the ship Ocean Guardian bored two holes into the seafloor at Axial Seamount, and both started venting fluid at about 500°F, Ars Technica reported. The 3-ton plant, named Adélie, was run from Seattle over the Regional Cabled Array, an undersea fiber-optic network operated by the University of Washington, according to ThinkGeoEnergy.

Then the well didn’t deliver. Canary Media reported that Adélie couldn’t produce power from it, so the team moved the unit to a natural vent nearby, and on September 27 the turbine made about 60 watt-hours over roughly 29 seconds. ThinkGeoEnergy says a battery protection system cut the run short, and a power cable failed on the restart. Redd told Canary Media the company follows the adage “make it exist, then make it good.”

Not everyone is sold on the idea. Stanford’s Roland Horne told Ars Technica it’s “probably technically feasible, but it would undoubtedly be more expensive than to do it on land.” Geologist Emily Pope told Canary Media it’s “an eyebrow-raising approach,” and Canary noted that remote island nations could far more easily adopt solar power and batteries.

Tonga is the real test. ThinkGeoEnergy reports that Endurance signed a memorandum of understanding with Tonga’s government and is targeting first electricity there in 2027. Before that, a refurbished unit called Gentoo goes down this winter (Ars Technica says the names are penguin-inspired). If you follow clean energy, I’d judge this one by whether Gentoo runs for minutes instead of seconds.

It works for seconds today, and Gentoo’s winter dive will show whether Endurance can make it run for hours.