If we can perfect this method, who needs any other form of energy? Yes we should keep producing Solar, Wind and Local geothermal. But with Deep Geothermal the only horizons we would have to conquer to be carbon free would be water shipping and air transport. Maybe Deep Geo could even make electric water transport possible. This stuff is so cool.
There’s treasure buried deep beneath the viridescent foothills of Tuscany’s Apennine Mountains, where the stark metal trusses of the Venelle-2 drilling tower mark its location like an X on a map. This geothermal well reaches nearly two miles beneath the surface to a region where temperatures and pressures are so high that rock begins to bend. Here, conditions are ripe for supercritical geothermal fluids, mineral-rich water that exhibits characteristics of both a liquid and a gas. It’s not exactly gold, but if Venelle-2 could tap into a reservoir of supercritical fluids and use them to spin a turbine on the surface, it would be one of the most energy-dense forms of renewable power in the world.
But getting there isn’t so easy. Boring deep into the ground risks triggering an earthquake if a large chunk of rock slips out of place. This risk was amplified at the Venelle-2 well, which aimed to breach the K horizon, a poorly understood boundary between the hard rock near the surface and the more pliant rock below. What would happen when the drill punched through this layer into the supercritical fluids below was anyone’s guess.
And for now, the mystery remains. Drilling at Venelle-2 stopped just shy of the K horizon when temperatures at the bottom of the well overwhelmed the equipment. Sensors at the bottom of the well indicated temperatures had breached 1,000 degrees Fahrenheit and pressures 300 times greater than at the surface. Nevertheless, Venelle-2 is the hottest borehole ever created, and it demonstrated that it’s possible to drill at the extreme end of supercritical conditions. And this week, a paper published in the Journal of Geophysical Research showed that it could be done without producing any major seismic activity.
The authors say they hope their study will assuage fears that all geothermal drilling causes earthquakes. After all, the public usually hears about geothermal wells only when something goes wrong. But Venelle-2 shows that “there are also many positive cases of wells drilled for geothermal purposes,” says Riccardo Minetto, a researcher at the University of Geneva and coauthor of the study.
Go there and read. More next week.