Bring up North Dakota and visions of oil boom towns might spring to mind. But there's another smaller energy revolution underway in the state. Geothermal energy installations rose 26 percent from 2010, a geologist with the North Dakota Geological survey told The Dickinson Press recently.
Geothermal heating and cooling systems -- which move heat through a network of pipes some 200 feet underground -- increased in North Dakota from 897 in 2010 to 1,135 in 2011. The rise is partially credited a 15 percent tax credit for geothermal heating and cooling systems. The federal government also provides a renewable energy tax credit for residents who install geothermal heat pumps. The potential for geothermal energy isn't limited to residents and business owners in North Dakota. Other states also offer geothermal heat pump tax credits.
UPDATE: It should be noted, thanks to one reader's suggestion, that shallow drilling to heat and cool residences and buildings is different than deep drilling for steam to generate electricity. North Dakota's geothermal boom relates to the installation of so-called "ground heat pumps." There's also potential for larger scale geothermal energy, which I discuss below.
Traditional geothermal energy involves locating and then drilling into naturally occurring pockets of hot water and steam. The amount of power that can be produced is dependent on the temperature and size of these pockets. Geothermal power isn't a primary energy source largely because these “pockets” are limited and dispersed widely across the United States.
A three-year project supported by Google.org and conducted by SMU Geothermal Laboratory estimates that "technical potential" for the continental U.S. exceeds 2,980,295 megawatts using enhanced geothermal systems (ESG) and other advanced geothermal technologies such as low temperature hydrothermal. To put that into perspective, currently there is 9,000 MW of traditional geothermal generating capacity installed in 24 countries around the world. The United States, the world’s largest geothermal energy producer, has about 2,800 MW of installed capacity, which generates enough electricity to power roughly 2.8 million homes.
EGS takes the basic concept of geothermal energy and uses technology to tap into the heat located under the Earth’s crust and replicate the naturally occurring water pockets. Theoretically, EGS can be developed anywhere there is hot rock — meaning any rock above 150 degree Celsius. The process involves fracturing hot rock and then circulating water through an underground system, which creates steam to drive a turbine and produce electricity. The water is then re-injected back into the rock, where the closed-loop cycle begins again.