BEAVER COUNTY, Utah – In a sagebrush valley full of wind turbines and solar panels in western Utah, Mr Tim Latimer gazed up at a very different device he believes could be just as powerful for fighting climate change – maybe even more.
It was a drilling rig, of all things, transplanted from the oil fields of North Dakota. But the softly whirring rig was not searching for fossil fuels. It was drilling for heat.
Mr Latimer’s company, Fervo Energy, is part of an ambitious effort to unlock vast amounts of geothermal energy from Earth’s hot interior, a source of renewable power that could help displace fossil fuels that are dangerously warming the planet.
“There’s a virtually unlimited resource down there if we can get at it,” Mr Latimer said. “Geothermal doesn’t use much land, it doesn’t produce emissions, it can complement wind and solar power. Everyone who looks into it gets obsessed with it.”
Traditional geothermal plants, which have existed for decades, work by tapping natural hot water reservoirs underground to power turbines that can generate electricity 24 hours a day. Few sites have the right conditions for this, however, so geothermal produces only 0.4 per cent of America’s electricity.
But hot, dry rocks lie below the surface everywhere on the planet. And by using advanced drilling techniques developed by the oil and gas industry, some experts think it is possible to tap that larger store of heat and create geothermal energy almost anywhere.
The potential is enormous: The Energy Department estimates there is enough energy in those rocks to power the entire country five times over and has begun a major push to develop technologies to harvest that heat.
Dozens of geothermal companies have emerged with ideas.
Fervo is using fracking techniques – similar to those used for oil and gas – to crack open dry, hot rock and inject water into the fractures, creating artificial geothermal reservoirs.
Eavor, a Canadian start-up, is building large underground radiators with drilling methods pioneered in Alberta’s oil sands. Others dream of using plasma or energy waves to drill even deeper and tap “superhot” temperatures that could cleanly power thousands of coal-fired power plants by substituting steam for coal.
Still, obstacles to geothermal expansion loom. Investors are wary of the cost and risks of novel geothermal projects. Some worry about water use or earthquakes from drilling. Permitting is difficult. And geothermal gets less federal support than other technologies.
Still, the growing interest in geothermal is driven by the fact that the United States has become extraordinarily good at drilling since the 2000s. Innovations like horizontal drilling and magnetic sensing have pushed oil and gas production to record highs, much to the dismay of environmentalists. But these innovations can be adapted for geothermal, where drilling can make up half the cost of projects.
“Everyone knows about cost declines for wind and solar,” said Ms Cindy Taff, who worked at Shell for 36 years before joining Sage Geosystems, a geothermal start-up in Houston. “But we also saw steep cost declines for oil and gas drilling during the shale revolution. If we can bring that to geothermal, the growth could be huge.”
States like California are increasingly desperate for clean energy sources that can run at all hours. While wind and solar power are growing fast, they rely on fossil fuels like natural gas for backup when the sun sets and wind fades. Finding a replacement for gas is an acute climate challenge, and geothermal is one of the few plausible options.
“Geothermal has historically been overlooked,” Senator Lisa Murkowski, who represents Alaska, said at a hearing. But with innovation, she added, “the potential is out there, I think, that’s pretty extraordinary.”
