What is the Most Common Geothermal Energy Use?

Mary McMahon
Mary McMahon

Geothermal energy use, harnessing the natural geothermal energy in the Earth, has been a part of human existence for centuries, with documented examples of geothermal energy use dating back to Greek and Roman times and being seen in Ancient China and Egypt. There are a number of ways in which this energy can be used, and it attracted a great deal of interest from alternative energy advocates in the early 21st century as people and governments sought out sources of renewable energy.

Heat generated beneath the earth's surface may be converted into electricity by geothermal power plants.
Heat generated beneath the earth's surface may be converted into electricity by geothermal power plants.

The most common geothermal energy use is direct use, in which heated water and steam from inside the Earth is used for heating, cooking, and bathing. Direct use is also the oldest use; the Greeks and Romans, for example, used geothermal springs for bathing and also attached beliefs about healing powers to deposits of naturally warmed water. This use can be seen in over 70 countries around the world, and is especially common in geologically active regions such as Iceland, where there is ample geothermal energy available.

Another form of geothermal energy use can be found in geothermal power plants, which use geothermal energy to generate electricity. The advantage of such facilities is that they can generate energy in a remote location and transfer it elsewhere, allowing people in regions without sources of geothermal energy to enjoy geothermal power. Efficiency rates for geothermal power plants can be very high, depending on the technology they use, how well they are maintained, and where the power is being sent.

There is an additional option for geothermal energy use known as a heat pump. With a heat pump, geothermal energy is used to push heat into buildings in the winter, and to pull heat out of buildings in the summer. This technique achieves climate control, often at very low cost. It relies on the natural warmth of the Earth near the surface, and does not require access to deep geothermal deposits. This geothermal energy use may be known as geoexchange so that people do not confuse it with the deep deposits of geothermal energy used in geothermal power plants and direct use systems.

This type of alternative energy has both advantages and disadvantages, as with every type of energy used by people to heat, fuel vehicles, cook, generate electricity, and perform other tasks. Many advocates for alternative energy have suggested that the solution to energy problems probably lies in a happy medium, with people combining energy sources and technologies to meet their needs, rather than relying on a single technology.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


This is a great article and discussion on how to use geothermal energy. I am now interested in knowing how geothermal heat pumps work. Does anyone know if there are any types of rebates or subsidies for geothermal heat pumps? How much would a system cost to heat and cool a 2800 square foot home? How reliable are the systems? I am really interested in learning more.


@georgesplane- I would tell you to examine your energy use. The use of geothermal energy in a geo-exchange system will be used to heat or cool some fluid to increase efficiency in your HVAC system. You will improve heating efficiency by up to 70% and increase your cooling efficiency by up to 50%, and you will also reduce your maintenance costs. Of course, the amount of increase in efficiency and reduction of costs depends on how efficient your current HVAC system is.

Installing a PV and solar water heating system will reduce the total amount of energy use, and significantly reduce your energy consumption for water heating. The efficiency of your solar system however, ultimately depends on how much sunshine you get and the amount of money you are willing to spend. I would recommend that you get an energy audit and discuss these options with your auditor. That person will be able to help you make an informed decision specific to your circumstances.


I want to lower my energy bill, but I am torn between technologies. I am trying to decide if I should purchase and install a geothermal heat pump, or if I should install a photovoltaic solar energy system and solar hot water heater. I cannot afford both, but I don't know enough about either to make the decision. I have a small parcel of land in rural central California so I have space and moderate sunshine.

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