Endurance Energy raises $54 million to harness a massive untapped energy resource

After you’ve finished working on rockets that find their way into outer space, it can be hard to think about a second chapter. For SpaceX alumnus Andrew Reed, that meant searching the depths of the ocean.

Reed, who grew up in the Pacific Northwest, a region affected by unusual heat waves and catastrophic fires in recent years, knew he wanted to tackle something in renewable energy.

“But my experience at a very powerful company like SpaceX made me realize that I couldn’t come up with an incremental solution,” says Reed, who was a Dragon and Starship engineer at SpaceX. “In fact, it had to be completely new and had to be approached from first principles.”

Redd left SpaceX and founded Endurance Energy, a startup that raised a $54 million Series A to harness terawatts of geothermal energy in the deep ocean, TechCrunch has learned. Founders Fund led the round with participation from Ascend, Construct Capital, Felicis Ventures, First Round Capital, Point72 Ventures, Riot Ventures, and Voyager Ventures. The new financing will allow the company to advance its power plant plans at a time when demand for energy from artificial intelligence data centers, electric vehicles and heavy industry is increasing.

Since founding the company last year, Reid has expanded the team to 25 employees, 12 of whom previously worked at SpaceX. The corporate vice president of engineering previously worked at merger startup Helion Energy.

Geothermal energy is not a new idea, and humans have been harnessing the Earth’s heat for thousands of years, whether from spa-like hot springs or geothermal power plants. But Reed, drawing on his experience at SpaceX, saw another opportunity that people were overlooking.

Here’s how he summed up the problem: Any energy source of the future must be renewable, or at least non-polluting, in his view. “This is non-negotiable,” said Reid, who is Endurance’s CEO. They must also be available 24/7 — or base-load power, as the industry calls it — and must be quickly deployable and capable of generating tens or hundreds of gigawatts of electricity, according to Reed.

He quickly ruled out nuclear power because regulatory and construction timelines could stretch for years. Solar and wind are not available 24/7 without batteries, and hydropower is limited in where it can be built (plus all the good sites have been taken). This left geothermal energy.

“Geothermal energy is the only primary energy that is deployable and renewable,” he said. “But why does it represent only 0.4% of the United States’ energy needs?”

There are other startups looking to harness geothermal energy, including Fervo and Zanskar. But these companies need to drill thousands of feet into the Earth’s crust to reach temperatures high enough to operate a power plant. Until now, the best opportunities for many geothermal startups have been in the western United States, far from large population centers.

The best places to drill, where the crust is thin and magma flows close to the surface, such as in Iceland or California, have long been claimed. More recently, startups like Fervo Energy, Until now, these sites were far from large population centers.

But no one exploited the oceans.

At several points around the world, Earth’s tectonic plates are moving apart, allowing hot magma to flow to the surface. The west coast of the United States, Japan, and much of Southeast Asia are located near the so-called “Ring of Fire,” the geologically active region surrounding the Pacific Ocean.

Going out to sea poses many challenges. Working underwater, at the depths suggested by the Endurance Program, is not easy. Robots will need to do a lot of work. Salt water is known to cause corrosion, so anything placed there will have to become harder against water pressure and corrosion.

But these are surmountable hurdles, Reed said, pointing to decades of experience in ocean drilling for oil and gas. He points out that endurance work should pose less risk to the surrounding environment. “If there’s an explosion — quotes — you’re leaking hot water into the ocean, which is already leaking terawatts throughout the Earth,” Reid said.

Some of the geothermal resources Endurance is eyeing are located a few dozen miles offshore, while others are a few hundred miles away. Which will be developed will be the product of an optimization algorithm that balances the cost of the submarine cable with the size of the resource and the size of the market on shore. (Reed says the company plans to avoid sensitive habitats such as those near hydrothermal vents.)

If Endurance taps just a small fraction of the geothermal potential there, it could generate a significant amount of electricity. Reed estimates there is about 6 terawatts that could be developed in the next five to 10 years around the Ring of Fire. To put this into perspective, the world uses on average about 20 terawatts across all energy sources at any given moment.

“The idea is that you can support any major coastal city that is on the Ring of Fire,” Reid said.