This is Climate Tech Distillery, a newsletter where I talk about one specific climate tech company every week.
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Today we'll distill a startup drilling into underwater volcanoes to generate clean baseload power 24/7, without sun, wind, or batteries: Endurance Energy 🇺🇸
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The grid needs clean power that never switches off. Here’s why that’s so hard:
1.Renewables clock out: Solar and wind are cheap, but they aren’t available 24/7 and the batteries to cover the gaps are expensive and short-lived. Grids still lean on fossil “baseload” to keep the lights on at 3am.
2.Islands pay the most: Remote places like Tonga still import diesel for roughly 80% of their electricity… dirty, volatile and absurdly expensive to ship across an ocean.
3.Alternatives are stuck: Nuclear gets tangled in decade-long permitting and construction. Hydro is tapped out since the best dam sites are already taken.
4.Demand is exploding: AI data centres, EVs and reindustrialization are pushing electricity demand to record highs. America is, in the industry’s own words, “running out of power.”
5. Onshore geothermal is tough: It’s still just 0.4% of U.S. energy because it requires drilling thousands of feet into hot rock, and the best sites are mostly in remote areas far from where power is needed.
Product / Service 📦
Endurance Energy builds generators that tap heat from underwater volcanoes along the Pacific Ring of Fire to produce clean baseload power. No fuel, no sun, no wind needed.
Always On, No Storage Required: Where tectonic plates split apart on the seafloor, magma heats water to 728°F. Endurance drills into those spots and generates electricity 24/7 from a heat source that never turns off. Also, super hot resources like these produce 5-10x more energy per well than conventional geothermal.
Modular and Scalable: Platforms anchor to the seafloor, drill into the thermal field, and spin high-pressure turbines to generate continuous electricity. The modular design means installations can be stacked to reach gigawatt scale at a single site.
First Target Customers: They’re going after island nations, industrial facilities, and hyperscale data centers, markets where baseload power is scarce or expensive. Islands pay a diesel premium; data centers pay a clean-power premium.
Subsea Servers: A conceptual long-term application involves co-locating subsea server modules directly with the ocean-floor generators, eliminating the need for onshore grid tie-ins entirely.
Market 🌐
The geothermal energy market is expected to grow from $9.81 billion in 2024 to $13.56 billion by 2030. But the offshore slice Endurance is targeting doesn't exist in any market report yet, which is the point.
The demand driver is AI. Data center load growth has tripled over the past decade and is projected to almost triple again by 2028, and tech giants are signing geothermal PPAs (Power Purchase Agreements) specifically because they need 24/7 clean power. Endurance targets the coastal and island markets that land-based geothermal can't reach.
Other Key Players
Fervo Energy🇺🇸: Next-generation geothermal power plants using advanced computational models, horizontal drilling, and distributed fiber optic sensing.
Eavor 🇨🇦: Specializes in closed-loop geothermal technology, offering dispatchable and baseload-capable power for commercial heating applications.
No other company in the sector has sought to develop the resource beneath the ocean floor.
Founding Story 🦄
Andrew Redd grew up in the Pacific Northwest, lately hit by heat waves and wildfires. He wanted to work in renewable energy, but after building Dragon and Starship at SpaceX, incremental wasn't an option: "It has to be brand new and approached from first principles."
In 2024 he founded Endurance Energy in Seattle, on the north shore of Lake Union, where the team loads seafloor drills straight onto outgoing vessels.
Since then: four prototype deployments to deep-sea volcanic systems as deep as 3,300m and as hot as 386°C, plus an agreement with the Government of Tonga to explore its waters. Their first end-to-end system, Adelie (100 kW), deploys at the Juan de Fuca ridge off Washington and Oregon later this year.
The team is now 25 people; 12 ex-SpaceX, plus a VP of Engineering from fusion startup Helion. Total raised: $84M in under two years, across a seed and a $54M Series A, both led by Founders Fund.
Top Impact Stats 📈
1. They believe 6 TW of geothermal capacity could be developed around the Ring of Fire in the next 5-10 years (~30% of current global energy consumption).
2. Pacific island nations pay up to 7x US electricity prices due to diesel dependence.
3. First grid delivery is targeted within two years; traditional geothermal takes 10+ years from discovery to power.
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