Seattle-based startup Endurance Energy recently tested the world’s first subsea geothermal power plant at Axial Seamount, an active underwater volcano about 300 miles (500 kilometers) off the coast of Oregon. The results, announced last week, show that its technology is technically feasible.

The company’s “Adélie” test plant harnessed the seamount’s hydrothermal fluid to generate 8.7 seconds of net-positive electricity, producing a median of about 2 kilowatts of net power and peaking at 16.5 kilowatts of net power. That’s a tiny amount of energy, but the goal of this first test was simply to show that Adélie could generate more than it consumes. With that milestone achieved, engineers can now work toward higher power and longer sustained generation, but getting there will be challenging.

Endurance, founded in January 2025 by former SpaceX engineer Andrew Redd, is considered the first commercial venture into subsea geothermal energy.…