Geothermal 101: The Basics and Applications of Geothermal Energy

The average household in the United States uses 56 percent of its energy consumption for heating and cooling, accounting for the single largest energy expense for homeowners. Also, buildings in the US are responsible for a large share of the nation’s energy consumption and carbon dioxide (CO2) emissions, representing 39 percent of total energy consumption and 43 percent of carbon emissions.

With growing concern over rising energy costs and the environmental impacts of supplying our energy needs, there is a great need to find economical and environmentally sound energy alternatives. However, amidst the push to expand renewable energies, one option that is rarely discussed is geothermal energy. One reason that geothermal is often overlooked is because of the lack of understanding how the technology works and a view that it is new and unproven. Actually, people have used geothermal energy for over 10,000 years with the first recorded use when Paleo-Indians settled around hot springs and used them as a source for warmth, cleansing, and healing. More advanced geothermal technology, such as geothermal heat pumps, have been used to heat and cool buildings since the late 1940s and today more than 50,000 units are installed in the United States every year.

While there are many ways in which geothermal energy can be applied, the focus of this paper is on residential applications of geothermal through the use of geothermal heat pumps (GHPs). Geothermal energy has significant potential as part of a renewable energy mix. Geothermal energy can be clean and reliable, and it is locally available in many areas. The purpose of this report is to provide an overview of the basics of geothermal energy: how it works, how it can be used, and the advantages and disadvantages of the technology.