Because the energy is generated right near the plant, it saves on processing and transportation costs compared to other types of fuel.

The initial costs of geothermal energy are high -- wells can cost $1 to $4 million each to drill, and installation of a home geothermal pump system can run as much as $30,000

However, a home geothermal energy pump can cut energy bills by 30 to 40 percent and will pay for itself within 5 to 10 years

It can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces.

It is an energy source that is considered renewable because both rain and heat in the earth replenish themselves naturally.

Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.

Hot water near the surface of Earth can be used directly for heat.

Geothermal power has massive potential in many areas of the U.S. but it has long remained a niche technology.