By KEVIN BESSLER for the Illinois Radio Network

SPRINGFIELD, Ill. (IRN) — As it becomes more expensive to heat and cool our homes, an Illinois energy specialist is touting the benefits of geothermal.

Geothermal energy is a renewable energy source because heat is continually produced inside the earth. Power plants use steam to produce electricity. The steam comes from reservoirs of hot water found below the earth’s surface.

Jay Solomon, energy specialist with the University of Illinois-Extension, said Illinois’ geographic location is perfect for geothermal systems.

“Illinois varies between about 50 degrees in the north end to about 60 degrees down in the Carbondale and further down areas of the state, so we have a nice range in there we can work with,” said Solomon.

While geothermal plants are typically constructed to service large regional populations, Illinois’ proposed deep direct-use system would operate on a smaller scale. The system would be used for space heating, air conditioning and refrigeration in a cluster of buildings on campus.

In 2008, the U.S. Energy Information Administration reported that about one-third of the entire U.S. energy demand was for thermal energy use. Eighty percent of this use was for heating at temperatures below 300 degrees Fahrenheit, which could be met by direct-use geothermal systems.

Solomon said the use of geothermal energy has been around longer than most people realize.

“The first really documented use was in 1807,” said Solomon. “The first ground-source heat pump was installed in a home in 1948.”

There are some downsides to the technology. Enhanced geothermal systems can trigger earthquakes as part of hydraulic fracturing. A project in Switzerland was suspended because more than 10,000 seismic events occurred over the first week of water injection.

Most of the geothermal power plants in the U.S. are in western states and Hawaii, where geothermal energy sources are close to the earth’s surface. California generates the most electricity from geothermal energy.