Huge shapes loom in the Nevada desert, reaching far beneath the surface, yet also stretching to the sky. Oil wells? No, although much of the technology is the same, and the exploration process is also similar. These are geothermal drills, taking heat from water pockets far below the surface, employing steam as a raw resource to turn a turbine and generate electricity. Geothermal power draws upon primordial heat from beneath the earth's surface: "At the Earth's core, 4,000 miles deep, temperatures can reach upwards of 9,000 °F (5,000 °C)" (Geothermal 101). Of course humans are not able to drill down that far, but we do go down several miles, using heat up to 662 °F (350 °C) (Brittanica).
Along with primordial heat we might expect hellish smoke, but that is far from the case. Although the vapor arising from geothermal wells might appear hazardous, it is almost entirely harmless steam. Like many other renewables, such as solar and wind, geothermal energy does not add to global warming or to local air pollution. Although receiving less media attention than solar and wind power, geothermal is likely to play a big part in our energy future. And geothermal is a constant, reliable resource, lacking the intermittency problems that plague some renewables.
Humans have used geothermal energy for longer than one might think, for instance by bathing in hot springs. For electricity generation, geothermal is still over 100 years old; the first such plant "opened at Larderello, Italy in 1904 and continues to operate successfully. The first commercial U.S. geothermal power plant . . . opened at The Geysers in California in 1960" and remains in operation (Geothermal 101).
By far the biggest geothermal success story is Iceland. Replete with geysers and volcanoes, that island country "is now fully powered by renewable forms of energy, with 17% of electricity and 87% of heating needs provided by geothermal energy" (Geothermal 101). Most of the rest of the world is not situated on top of such an abundant, accessible energy source. Nevertheless, with greatly expanded grid capacity, geothermal electricity could be sent from areas with good underground resources to those without.
Another geothermal source is even closer at hand, only about ten feet (3 meters) below us, and already in use. This is heat absorbed from the sun, stored in the earth, and available via Geothermal Heat Pumps (GHPs)-a sometimes overlooked subset of the already overlooked geothermal field. GHPs can heat and cool homes and buildings (and even heat water), greatly lowering electricity costs virtually anywhere. Still another technology, Enhanced Geothermal Systems (EGS), while still in early stages of research and development, has the potential to provide electricity in a great diversity of environments.
Go To Geothermal Heat Pumps
Special thanks to the Geothermal Energy Association for their help with this Discovery Guide