
Fervo Energy, a geothermal power startup, began conducting an experiment deep below the desert floor of northern Nevada. It pumped water thousands of feet underground and then held it there, watching for what would happen. The readings from gauges planted throughout the company’s twin wells showed that pressure quickly began to build, as water that had nowhere else to go actually flexed the rock itself. When they finally released the valve, the output of water surged, and it continued pumping out at higher-than-normal levels for hours. The results from the initial experiments suggest Fervo can create flexible geothermal power plants, capable of ramping electricity output up or down as needed. Potentially more important, the system can store up energy for hours or even days and deliver it back over similar periods, effectively acting as a giant and very long-lasting battery.