Novel Geothermal System to Come Online in Germany
_This article was originally published by_ _Canary Media_.
Eavor, an advanced-geothermal startup, says it has significantly reduced drilling times and improved technologies at its nearly online project in Germany—milestones that should help it drive down the costs of harnessing clean energy from the ground.
In late October, the Canadian company released results from two years of drilling activity at its flagship operation in Geretsried, Germany, giving Canary Media an exclusive early look. Eavor said the data validates its initial efforts to deploy novel “closed-loop” geothermal systems in hotter and deeper locations than conventional projects can access.
“Much like wind and solar have come down the cost curve, much like unconventional shale [oil and gas] have come down the cost curve, we now have a technical proof-point that we’ve done that in Europe,” Jeanine Vany, a cofounder and executive vice president of corporate affairs at Eavor, said from the Geothermal Rising conference in Reno, Nevada.
Eavor is part of a fast-growing effort to expand geothermal energy projects beyond traditional hot spots like California’s Salton Sea region or Iceland’s lava fields. The company and other firms—including Fervo Energy, Sage Geosystems, and XGS Energy—are adapting tools and techniques from the oil and gas industry to be able to withstand the harsh conditions found deep underground.
The industry wants to produce abundant amounts of clean electricity and heat virtually anywhere in the world, and it could serve as an ideal, around-the-clock pairing to solar and wind power. But geothermal companies are only just starting to put their novel technologies to the test.
## Eavor’s Geothermal Breakthrough in Germany
Eavor began drilling in Geretsried in July 2023, shortly after winning a $107 million grant from the European Union’s Innovation Fund. For its first “loop,” the company drilled two vertical wells reaching nearly 2.8 miles below the surface, then created a dozen horizontal wells—like tines of a fork—that each stretch 1.8 miles long. Once in place, the wells are connected underground and sealed off so that they operate like radiators: As water circulates within the system, it collects heat from the rocks and brings it to the surface.
Operations on the first of four loops are nearly complete, and the startup plans to begin construction on its second loop in March 2026. All told, the system will supply 8.2 megawatts of electricity to the regional grid and 64 MW of district heating to nearby towns, operating flexibly to provide more heat during chilly winter months and produce more electricity in summer.
In its new paper, Eavor said it encountered significant challenges in drilling its first eight of twelve lateral wells, which took over 100 days to complete—a major expense in an industry where drilling rigs can cost about $100,000 a day to run. But the company said it improved its techniques and adapted its equipment in ways that reduced the drilling time for the remaining four wells by 50 percent.
For example, Eavor said it successfully deployed an insulated drill pipe technology, which can actively cool drilling tools even as they encounter increasingly hotter conditions underground and helps to increase drilling speed. The adjustments also enabled Eavor to triple the length of time its drill bit could run before wearing out, further reducing downtime during the operation.
On top of cutting drilling time and costs, these improvements should also pave a path to boosting Eavor’s thermal-energy output per loop by about 35 percent, Vany said.
The Germany project will be the first commercial system of its kind when it starts producing power later this year. But other next-generation approaches—like the enhanced geothermal systems that Fervo is building in Utah and operating in Nevada—are also scaling up.
## Challenges in Geothermal Drilling
Enhanced geothermal involves fracturing rocks and pumping down liquids to create artificial reservoirs. The hot rocks directly heat the liquids, which return to the surface to make steam. This approach is relatively more efficient at extracting heat from the ground, but it can also raise the risk of inducing earthquakes or affecting groundwater—though experts say that’s unlikely to happen in well-managed projects. In places that ban fracking, like Germany, closed-loop systems can still move forward.
But the closed-loop design has trade-offs of its own, said Jeff Tester, a professor of sustainable energy systems at Cornell University and the principal scientist for Cornell’s Earth Source Heat project. Namely, the pipes can limit the transfer of heat from the underground rocks to the fluids inside the pipe, which in turn limits how much energy a system can produce.
“While companies developing closed-loop systems can make them work, the main challenge they face is for fluid temperatures and flow rates to be high enough to pay off economically,” Tester said. “You can get energy out of the ground; it’s just, how much can you sustainably and affordably produce from a single closed-loop well connection?”
Vany said that Eavor’s modeling shows its technology is already in line with the “levelized cost of heat” in Europe, which estimates the average cost of providing a unit of heat over the lifetime of the project. That figure can fluctuate between $50 and $100 per megawatt-hour thermal in the region’s volatile energy market, she said.
“After we’ve drilled those first four loops, we will be at the bottom of the learning curve,” Vany added. “And that’s the purpose of the Geretsried project.”
