The archive · Climate & Energy · Technical decision · 2017–2026
Eavor's closed-loop bet pays off: world-first geothermal loop power on German grid
Calgary startup's sealed Eavor-Loop wells — no fracking, no reservoir — deliver first commercial closed-loop geothermal electricity in Bavaria, December 2025.
Eavor Technologies
What the business is
Builds Eavor-Loop closed-loop geothermal plants: sealed multilateral wells circulate a working fluid through hot rock to deliver 24/7 power and district heat.
How it started
Founded in 2017 in Calgary by John Redfern, Paul Cairns and Jeanine Vany to remove the two things that make conventional geothermal a lottery: the need for naturally hot, permeable reservoirs and the risk of pumping water into the ground. The Eavor-Loop is a sealed radiator of wells — two vertical bores joined by long horizontal laterals — with fluid circulating by thermosiphon, needing no pump. A prototype, Eavor-Lite, validated drilling, sealing and the thermodynamics in Alberta from 2019.
What happened
At Geretsried, Bavaria — originally drilled as a conventional geothermal project and abandoned after hitting hot, dry granite — Eavor began construction in October 2022 and drilling in July 2023, backed by a €91.6 million EU Innovation Fund grant, a nearly €45 million EIB InvestEU loan, and German feed-in tariffs around €250/MWh. The plant deploys four Eavor-Loops (64 MWth, 8 MWe) built from two vertical wells and 12 lateral bores, each wellbore pair 16 km long, connected underground with active magnetic ranging; drilling time per lateral fell by 50% as the team iterated.
How it ended up
On December 4, 2025, Eavor delivered the world's first electricity from closed-loop multilateral wells to the German grid — the first commercial closed-loop geothermal plant anywhere. The system reached operation in under 30 minutes, runs pump-free via thermosiphon, and Eavor is scaling the model to further projects.
Background
Eavor Technologies, founded in Calgary in 2017, bet that geothermal power did not have to depend on nature's accidents. Conventional geothermal needs hot, permeable, water-filled reservoirs — found mainly in volcanic regions — and often injects water into the ground under pressure. Eavor's answer, the Eavor-Loop, is a sealed radiator of wells: two vertical bores joined by long horizontal laterals that absorb heat from surrounding rock by conduction, with a working fluid circulating by thermosiphon, no pump and no fluid exchange with the ground.
The company de-risked the idea in steps: the Eavor-Lite prototype in Alberta validated drilling, sealing and thermodynamics from 2019, and deep-drilling programs in New Mexico tested the hardest conditions. Then it took on Geretsried in Bavaria — a site that had been drilled for conventional geothermal and abandoned after hitting hot, dry granite with no permeability, precisely the geology that kills traditional projects.
Construction at Geretsried began in October 2022 and drilling in July 2023, financed by a €91.6 million EU Innovation Fund grant, a nearly €45 million EIB InvestEU loan, and German feed-in tariffs of roughly €250/MWh. The plant uses four Eavor-Loops rated at 64 MWth and 8 MWe, built from two vertical wells and twelve lateral bores — each wellbore pair about 16 km long — connected underground with magnetic ranging. Drilling time per lateral fell 50% over the campaign.
On December 4, 2025, Eavor began delivering the world's first electricity from closed-loop multilateral wells to the German grid: the first commercial closed-loop geothermal plant anywhere, and proof that a sealed, conduction-based system can produce firm, 24/7 power outside volcanic regions. The company is now pushing the technology into new geographies and projects, with the Geretsried plant operating as the reference case.
What has to be true
- Conventional geothermal is a site lottery; Eavor removed the requirement for hot, permeable reservoirs entirely, making the resource geography-independent.
- A sealed, pump-free thermosiphon loop cuts operating costs, water use and induced-seismicity risk — the three classic objections to geothermal.
- Choosing a failed conventional site as the first commercial project made success proof, not theory: if Geretsried works, marginal geology works.
- European policy money (EU Innovation Fund, EIB, feed-in tariffs) covered first-of-a-kind risk that venture capital alone would not have carried.
- The 2025 grid connection created a reference asset that converts a hard-tech thesis into a bankable project template.
What can be applied
Remove the rare resource: by not needing hot, permeable reservoirs, Eavor turned geothermal from a site lottery into an engineering problem — proven on geology that had already failed.
Aftermath
As of September 2026, the Geretsried plant is operating commercially: up to 64 MWth of heat and 8 MWe of power to the Bavarian grid and local municipality, running pump-free on thermosiphon after a start-up of under 30 minutes. Eavor reports a steep drilling learning curve — about 50% less time per lateral and three times longer bit runs — and is applying the template to further projects, backed by bp, Chubu, Temasek, BHP, Microsoft's Climate Innovation Fund and Canada Growth Fund. The open question is whether closed-loop drilling economics can beat conventional geothermal at scale.
Sources
- Eavor Technologies Achieves First Electricity Production at Geretsried Site
- Eavor's First-of-Its-Kind Closed-Loop Geothermal Project Produces Grid Power in Germany
- Geretsried Project
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