Geothermal energy was once confined in theory to areas of geothermal activity, but if one drills deep enough, there's extreme heat from the planet's core essentially everywhere to be harnessed to make steam and drive turbines to create carbon-free electricity 24 hours a day when the wind isn't blowing and the sun isn't shining.
For this reason, Google made an early bet on this enhanced geothermal technology, and partnered with the Utah-based Fervo Energy, which uses drilling techniques from the oil and gas industry to create a first-of-its-kind power plant in Nevada.
GNN reported that initial tests in July showed that the technology was working, in which the hypothesized 3.5 megawatts were indeed being delivered.
A borehole was made 8,000 feet into the desert plains before being extended horizontally 3,000 feet. A second, shallower tunnel was drilled above it. As cold water is pumped into the lower shaft, heat causes it to rise through cracks in the rock created by fracking into the upper shaft, a process which heats it well above supercritical temperatures of 200°F.
Once topside, the superheated fluid boils another well of water to create steam to drive a turbine and power Google's Henderson City data center with a combination of storage and solar power.