“Last year Fervo successfully completed a pilot project in Nevada, and secured Google as an early customer. In June it confirmed that Southern California Edison, a big power utility, had agreed to buy 320 megawatts of power from its much bigger new project in Utah, which aims to apply mass-manufacturing methods to scale the pilot technology. The deal is the largest-ever power purchase agreement for geothermal energy.

On September 10th Fervo revealed yet more good news. Despite needing to drill much deeper at its Utah site, it was able to do so in just 21 days, slashing its drilling time by 70% relative to the Nevada site. It was also able to drill the fourth of its wells at half the cost it took to drill the first, mainly thanks to ‘learning by doing’. The firm has already outpaced the targets America’s Department of Energy (DOE) set for geothermal energy producers to reach by 2035.

Hot rocks might also turn out to be surprisingly effective batteries. A paper published in January in Nature Energy, a journal, argues that EGS sites can be operated flexibly, with more water injected underground when needed to build up pressure and liquid released on demand to make power.”

From The Economist.