A Google.org-funded study by Southern Methodist University pegs America’s geothermal potential at three million MW. The research team used more than 35,000 data sites to create what Google says on its website are the most data rich maps of geothermal energy in the U.S. The company put the findings on its Google Earth map for all to see.
West is the best. That’s been the common thinking about geothermal, and though this study doesn’t alter that, it reveals impressive geothermal capability in the east as well. West Virginia could be as geothermally endowed as it is coal rich. Other hot spots include the Appalachians, Gulf Coast, and northern Louisiana.
How Geothermal Power Plants Work
Earth’s constantly hot core radiates heat towards the surface. Sometimes it actually flows to the surface as lava, but usually remains below, heating up underground water reservoirs, in some cases as hot at 700ºF, creating steam. Geothermal power plants have traditionally tapped into the easily accessible locations where hot springs and geysers occur because they need to access water as a heat transfer agent, but advanced technology called enhanced geothermal system (EGS), sometimes referred to as engineered geothermal power plants, have changed that.
Today’s systems can make use of dry rock by digging injection wells, then pumping water down those wells, so it gets heated up by the hot rock. High pressure sends the water coursing through porous rock and back up through production wells. As geothermal technology improves, power plants will be able to drill deeper to get to the hotter part of the Earth’s crust and make better use of cooler heat sources.
Geothermal heating and cooling can also be used at the micro level and is an excellent way to stave off hot summers or cold winters without cranking the gas or AC. Check out our geothermal guide for homeowners for more info.
An Alternative to Coal
It’s estimated that the United States contains the greatest recoverable coal reserves in the world — 273 billion tons — making it the country’s most abundant energy resource. Easy access to cheap coal has caused its use to triple in the past 30 years, now accounting for approximately half of the country’s electricity generation. According to Energy Information Administration (EIA) projections, coal dependence isn’t likely to decline anytime soon. It’s projected to grow at an average rate of 1.1% to 1.5% annually heading towards 2025.
Coal abundance isn’t the only reason for its proliferation. Many states in the east have huge reserves, but aren’t as resource rich when it comes to cleaner forms of energy, such as solar or wind. Given the economics, these states naturally turn to coal. With America’s geothermal capability in the public consciousness and advanced technology making access to geothermal resources easier, geothermal can displace a huge chunk of coal power usage in the future if acted upon.
The brightest ray of hope that comes from the study is perhaps that the major coal-producing states, which aren’t renewable-resource rich, can turn to geothermal as a viable alternative form of energy. This constant power source lies underfoot at all times and the technology is there to effectively tap it, all that’s needed is the will to do so and a bit of up front capital strategically invested.
