Heat from the Earth, or geothermal — geo (Earth) + thermal (heat) — energy can be and already is accessed by drilling water or steam wells in a process similar to drilling for oil. Geothermal energy is an enormous, underused heat and power resource that is clean (emits little or no greenhouse gases), reliable (average system availability of 95%), and homegrown (making us less dependent on foreign oil).
Geothermal resources range from shallow ground to hot water and rock several miles below the Earth's surface, and even farther down to the extremely hot molten rock called magma. Mile-or-more-deep wells can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in a variety of applications. (From the Geothermal Basics webpage of the U.S. Department of Energy's Energy Efficiency and Renewable Energy division website.)
Thinking about Geothermal Energy for Your Home or Business?
Geothermal Heat Pumps are devices that take advantage of the relatively constant temperature of the Earth's interior, using it as a source and sink of heat for both heating and cooling. When cooling, heat is extracted from the space and dissipated into the Earth; when heating, heat is extracted from the Earth and pumped into the space. (From the Geothermal Glossary provided by the U.S. Department of Energy's Energy Efficiency and Renewable Energy division website.)
For more information see the U.S. Department of Energy site on Geothermal Heat Pumps.
Learn More about Geothermal Energy
See the U.S. Department of Energy's Geothermal Technologies Program.