Geothermal energy (SG-05)
Despite tremendous heat within the earth, it will be some time before thermal energy can be used to heat homes in Indiana. Rocks near the surface here are at about 55⁰ F, the average of year-round daily temperatures, but increase with depth at a rate of about 1 degree F for each hundred feet below the surface. In a mine in Ohio, for example, rock temperatures are 85⁰ F at a depth of 2,200 feet.

In many western and some eastern localities, geothermal energy is evident at the surface as hot springs and geysers. In many of these regions geothermal energy is being put to practical use. In Indiana, however, to "mine" these resources, holes would have to be drilled to great depths at prohibitively high costs.

Our Hoosier State Beneath Us: Structural Geology