We’re in the Loop on Geothermal Energy

An Alberta company is piloting a closed-loop system that could help bring clean, sustainable geothermal energy to more places worldwide.

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The inner core of the Earth approaches the temperature of the surface of the sun. That’s a massive source of clean and sustainable power, and geothermal energy taps into that resource.

But the global expansion of geothermal has been held back in part by the availability of aquifer sites where this heat actively circulates close to the Earth’s surface; these are normally near the boundaries of tectonic plates, where we often find features like volcanoes, hot springs, and geysers.

Calgary-based Eavor Technologies wants to change this by creating a closed-loop system that could make it the first truly scalable and on-demand solution. The $10-million pilot — funded by the Government of Canada, Alberta Innovates, and Emissions Reduction Alberta — aims to prove that the technology works so that it can be picked up commercially.

Canada is already a leader in renewable energy, but solutions like solar or wind are intermittent, and hydroelectricity can only reach a certain maximum scale. The Eavor-loop pilot will capitalize on Canada’s expertise and infrastructure for drilling wells to extract geothermal energy without fracking or water use.

Unlike conventional wells that produce brine from subsurface aquifers, Eavor-loop is a closed and sealed system that circulates a proprietary fluid underground where it picks up heat. The pilot will start by drilling a pair of wells 2 km apart and 2.4 km into the ground. This is much deeper than a conventional geothermal well, meaning the Eavor loop can access hotter temperatures.

Once the vertical shafts have reached their final depth, drilling will make a right turn and continue laterally until they connect to form a U-shaped well. The circuit will be closed by a surface pipeline joining the two wells above ground.

All of this happens underground with only small surface units, boasting a surface footprint so small that it could fit into a backyard. Multiple lateral lines can be added to join the same well pair to scale up energy collection, and ultimately a second well pair installed back-to-front can also eliminate the surface pipeline.

The entire system is sealed and it works like a giant radiator, and it doesn’t require any pumps for the working fluid to circulate. The fluid naturally circulates via a thermosiphon effect, with hot fluid rising through the outlet well and cool fluid falling into the inlet well. Once the heated fluid reaches the surface, it can be used directly to heat buildings or homes, or to drive heat engines for power generation.

“Innovative projects like the one developed by Eavor Technologies Inc. demonstrate how a strong economy and a clean environment go hand in hand,” said Navdeep Bains, Canada’s Minister of Innovation, Science and Economic Development, in a press release.

“Today’s investment will not only help develop the next generation of geothermal engineering but will also help create and maintain jobs in the energy industry.”

By making geothermal energy accessible to more diverse sites, the Eavor-loop could finally bring geothermal energy into common use worldwide. It could be especially valuable in remote areas where supplying electricity remains a challenge.

“We look forward to the construction and completion of the demonstration facility right here in Alberta this summer,” adds John Redfern, president and CEO of Eavor Technologies.

“The demonstration of our technology and solution will provide the validation needed to unlock Eavor’s already-identified commercial opportunities at home and around the world.”

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Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.