‘Closed-loop’ technology brings promise of geothermal anywhere

Eavor, a clean energy start-up founded in 2017, completed last year a first prototype of closed-loop geothermal power plant to deliver energy in Alberta, Canada.

This article is part of our special report Geothermal energy.

Geothermal energy has until now been constrained to areas with special geological conditions where the earth’s heat is close to the surface. Today, closed-loop technologies make geothermal accessible almost anywhere in the world, opening up new prospects for mass-scale deployment.

Eavor, a clean energy start-up founded in 2017, completed last year the first prototype of a closed-loop geothermal power plant to deliver energy in Alberta, Canada.

Now, the Calgary-based company intends to deploy similar plants in Germany and gradually scale up its technology across Europe, thanks to backing from new investors.

The ‘Eavor Loop’, as the company calls its closed-loop technology, is a new generation of Advanced Geothermal Systems (AGS). It connects two vertical wells with many horizontal wellbores, which all together create a closed buried-pipe system.

These systems do not require the injection or extraction of any fluids from the earth. Contrary to deep geothermal techniques, it therefore does not require fracking – the controversial drilling process used in the extraction of shale gas.

“The system provides energy 24/7, independent from weather, season or if it’s day or night,” said Daniel Moelk, country manager for Germany at Eavor. “We can also dispatch the load and follow wind and solar by reducing the energy output when we have lots of wind and solar in the grid. And if these drop out, we can provide peak load,” he told EURACTIV.

“Therefore, we can work as a renewable battery without actually having to construct a battery or construct an energy storage facility,” he explained.

Geothermal energy has traditionally been developed in areas offering specific seismic and volcanic conditions, such as Iceland or Turkey, which have conventional hydrothermal sources.

But as Europe looks at measures to decarbonise its heating systems, some cities like Munich and Paris – which are sitting on deep aquifers – are now betting on geothermal energy to deliver heat and electricity in urban areas.

And closed-loop systems could offer them an option.

“I think there are places on earth where a closed loop might be the only technology that can offer a constant baseload,” said Marit Brommer, executive director at the International Geothermal Association (IGA). “We need to demonstrate the technology at scale to understand how it serves this constant supply of electricity and heat,” she said.

'Sun beneath our feet': The European cities turning to geothermal

A growing number of cities in Europe are betting on geothermal to provide households with clean heating, but the little-known renewable energy source will need more attention from Brussels in order to scale up.

Borrowing from the oil and gas industry

Closed-loop geothermal systems, as well as other deep-drilling technologies, could also bring an additional benefit: They enable the redeployment of both technologies and workers from the oil and gas industry who have prior experience in the field.

“The only other industry that goes down to those depths to try and visualise and understand what’s going on down there is predominantly the oil and gas industry,” said Robert Winsloe, vice-president for Business Development at Eavor.

“And in fact, the reason why the economics for the Eavor-Loop work is, ironically, because of the shale industry in North America,” he said.

“This means that once we begin to scale quickly that volume, then we will be able to redeploy thousands of people from the oil and gas industry and redeploy a lot of that same technology as well,” he told EURACTIV.

Oil and gas companies have accumulated decades of experience in drilling wells and exploring geological formations. Industry experts believe they could use the vast amounts of data collected over the years in the geothermal industry.

In fact, some of them have already started investing in geothermal. Earlier this year, oil majors including BP plc and Chevron invested $40 million in Eavor, hoping to build on the fossil fuel industry’s drilling experience to expand the company’s activities across the globe.

Risk and reward

It will not be an easy ride, though. Deep geothermal technologies have so far used fracking, or high-pressure water, to fragment the rock and access heat sources deep underground.

This has caused public rejection in places like Strasbourg, France, where geothermal projects have caused tremors in the recent past.

“We need to communicate well our technology. Because we are not connecting to any hydrological aquifers, we have eliminated the risk of a seismic event during drilling,” Eavor’s Moelk said.

“We cannot cause any earthquakes, and we cannot contaminate drinking water,” he stressed.

Because of those setbacks, environmental and geological risk assessments related to geothermal have also become more stringent over the years.

“If there’s one thing that oil and gas is good at is exactly that: it is the risk management and the de-risking of the subsurface where the oil and gas industry has so much more knowledge of because they have drilled millions of wells,” said the IGA’s Brommer.

“We need to be crystal clear on what we do, how we do that, how we manage everything in the subsurface, and take people with us in that journey. Because if we don’t do that, I am very much concerned that the social acceptance that we worked so hard to gain will be lost,” she added.

Tremor around geothermal plant in France puts spotlight on safety

A series of minor human-induced earthquakes in the area of Strasbourg, eastern France, last December has reminded local inhabitants about the safety of geothermal energy, highlighting the challenges faced by deep drilling technology.

[Edited by Frédéric Simon / Zoran Radosavljevic]

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