Startup generates electricity from underwater volcano in world-first test

Endurance Energy, a startup based in Seattle, has completed the world's first demonstration of a subsea geothermal power plant near an active underwater volcano almost a mile below the ocean surface. The three-week test deployment in September at the Axial Seamount in the northeast Pacific Ocean involved a 3-ton prototype that generated less than 10 seconds of net-positive electricity.

Founder and CEO Andrew Redd said the deep ocean provides advantages for the technology. “The deep ocean gives us unlimited cold seawater for cooling, and its weight keeps the system and the well pressurized, so our plants can be compact,” Redd said in an email to Ars Technica.

Endurance Energy aims to eventually commercialize the technology, targeting Pacific island nations and other customers seeking alternatives to importing expensive fossil fuels. The short burst of energy was enough to demonstrate technical feasibility, the company said, but significant engineering challenges remain before the system can be scaled up for commercial use.

Analysis

Why This Matters

The successful test opens the possibility of tapping geothermal heat from underwater volcanic systems, a largely untapped renewable energy source.
If commercialized, subsea geothermal could provide baseload power for island nations currently reliant on imported diesel or other fossil fuels.
The demonstration moves the technology from concept to reality, but the brief duration of power generation highlights the long road ahead to practical deployment.

Background

Geothermal energy on land is well established, especially in volcanically active regions like Iceland and New Zealand. However, most of Earth's volcanic activity occurs underwater, along mid-ocean ridges. Capturing that heat has been considered technically daunting due to extreme pressure, corrosive seawater, and the difficulty of operating equipment at depths of nearly a mile. Endurance Energy's test is the first known attempt to generate net electricity from a submarine hydrothermal system.

Key Perspectives

Endurance Energy: The startup views the test as a successful proof of concept that validates its compact power plant design. It sees a market in Pacific island nations that pay high prices for imported fuel and already rely on undersea cables for communication, making offshore energy infrastructure more familiar. Pacific island nations: These countries face some of the highest electricity costs in the world due to reliance on diesel. A reliable, locally sourced renewable baseload power source could reduce energy poverty and improve energy security. Skeptics: The 10-second power generation is far from demonstrating economic viability. Technical hurdles include long-term corrosion resistance, maintaining pressure seals at depth, and the cost of installing and maintaining equipment on the seafloor. Scaling from a 3-ton prototype to a commercial plant may prove extremely expensive.

What to Watch

Whether Endurance Energy can extend net-positive generation from seconds to minutes or hours in a follow-up test.
Any partnerships with Pacific island governments or utilities that would provide funding and a deployment site.
Progress on materials science for deep-sea, high-temperature, high-pressure environments.

Checked

9 claims in this story checked against 1 source: 8 supported.

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SupportedStartup generates electricity from underwater volcano in world-first testArs Technica - All content: “The world’s first demonstration of a subsea geothermal power plant has taken place near an active underwater volcano”
SupportedSeattle-based Endurance Energy demonstrates subsea geothermal power at Axial SeamountArs Technica - All content: “Endurance Energy, the Seattle-based startup... test deployment at the Axial Seamount”
SupportedThe test produced less than 10 seconds of net-positive electricityArs Technica - All content: “generated less than 10 seconds of net-positive electricity”
SupportedThree-week test deployment in September at Axial SeamountArs Technica - All content: “three-week test deployment of the 3-ton prototype power plant took place at the Axial Seamount in the northeast Pacific Ocean in September”
Supported3-ton prototypeArs Technica - All content: “3-ton prototype”
SupportedAlmost a mile below the ocean surfaceArs Technica - All content: “almost a mile below the ocean surface”
SupportedDirect quote: 'The deep ocean gives us unlimited cold seawater for cooling, and its weight keeps the system and the well pressurized, so our plants can be compact,' said Andrew Redd in an email to Ars Technica.Ars Technica - All content: ““The deep ocean gives us unlimited cold seawater for cooling, and its weight keeps the system and the well pressurized, so our plants can be compact,” said Andrew Redd , founder and CEO of Endurance Energy, in an email to Ars.”
SupportedEndurance Energy aims to commercialize technology targeting Pacific island nations and other customersArs Technica - All content: “aims to eventually commercialize subsea geothermal power for Pacific island nations and other customers looking for alternatives to importing expensive fossil fuels”
Partly supportedThe short burst of energy was enough to demonstrate technical feasibility, the company said, but significant engineering challenges remain before scaling up.Ars Technica - All content: “showed the technical feasibility”