The technique known as fracking has become a dirty word in the UK, synonymous with environmental damage and public opposition. But a new generation of start-ups is repurposing that very same technology to drill for a cleaner, always-on energy source that lies just beneath our feet: geothermal heat.
Geothermal energy exploits the natural heat below the Earth's surface, and with next-generation technology, companies can now reach hotter, deeper and more varied locations than ever before. The approach is winning rare bipartisan support in the United States. “It's the same techniques and up to a point it's the same industry as well,” says Gernot Wagner, a climate economist at Columbia Business School in New York. “But from a climate perspective, there's a huge difference.”
“Start-ups are repurposing fracking technology for geothermal energy, winning rare bipartisan US support and potentially changing the UK's energy debate.”
In the US, politicians on both sides see something to like. Liberals are drawn to the low greenhouse gas emissions of geothermal plants, while conservatives appreciate the energy independence and the use of drilling technology familiar from oil and gas. Some states are already accelerating permits for new plants, and in April senators from both parties introduced the Next-Generation Geothermal Research and Development Act. If passed, the legislation would direct the Department of Energy to support the development and commercialisation of next-generation geothermal systems.
One emerging type is known as enhanced geothermal systems (EGS), which uses hydraulic fracturing – better known as fracking – to create underground fractures. Pressurised fluid is pumped into one well, and steam or hot water is collected from another. The technique has stirred deep controversy in the UK, where fracking for oil and gas was effectively banned. But Wagner argues that the seismic risks are outweighed by the benefits: a renewable source that is always on and offers large-scale capacity. “Based on where we are, moving much faster, much bigger in the direction of using much more geothermal, frankly, is all good news,” he says.
To go faster and deeper, however, will require advances in drilling technology. Companies are developing more stable drill bits that can break through hard rock at high temperatures. Some are even trying to bypass conventional drills entirely. Quaise, a company with roots at the Massachusetts Institute of Technology (MIT), is using millimetre wave drilling – a frequency similar to microwaves. Harry Kelso, Quaise's communications manager, explains that the technology involves “sending electromagnetic waves in the microwave millimetre wave spectrum to essentially melt and vaporise through the rock.”
Traditional geothermal energy has been limited to hotspots where very hot rocks are easily accessed near the surface. Millimetre wave drilling, Kelso says, “really enables you to access super-hot geothermal” in places previously out of reach. For a country like the UK, still wrestling with its energy future, the question is whether this abundant but expensive source can finally deliver the clean, reliable power that conventional fracking never could.