What is Geothermal Energy? Can it Be Utilized in Your Home?

What is geothermal energy? Simply put, it is energy from the Earth. Geo refers to the solid part of the Earth and thermal refers to heat energy. Anywhere the Earth's surface is in close proximity to magma or volcanic activity under or near the Earth's surface, we can harness the energy.

According to the Department of Energy,"Geothermal energy technologies use the heat of the earth for direct-use applications, geothermal heat pumps, and electrical power production. 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.

Three power plant technologies are being used to convert hydrothermal fluids to electricity. The type of conversion used depends on whether the fluid is steam or water and its temperature.

Dry Steam Power Plants

What is Geothermal Energy? It is found in steam plants that use hydrothermal fluids that are primarily steam. The steam goes directly to a turbine, which drives a generator that produces electricity. The steam eliminates the need to burn fossil fuels to run the turbine. This is the oldest type of geothermal power plant. Steam technology is used today at The Geysers in northern California, the world's largest single source of geothermal power. These plants emit only excess steam and very minor amounts of gases as waste.

Geothermal Power dry steam

Flash Steam Powerplants

What is geothermal energy? It utilizes hydrothermal fluids above 400 degrees F that can be used in flash plants to make electricity. Fluid is sprayed into a tank held at a much lower pressure than the fluid, causing some of the fluid to rapidly vaporize, or "flash," to steam. The steam then drives a turbine, which drives a generator. If any liquid remains in the tank, it can be flashed again in a second tank to extract even more energy. Only excess steam and trace gases are byproducts.

Geothermal Power Flash Steam

Binary Cycle Power Plant

Here is the system that most people would have as a resource. It is the most common if you are fortunate to live in an area that has geothermal opportunities. Most geothermal areas contain moderate-temperature water (below 400 degrees F). Energy is extracted from these fluids in binary-cycle power plants. Hot geothermal fluid and a secondary fluid with a much lower boiling point than water pass through a heat exchanger.

Heat from the geothermal fluid causes the secondary fluid to flash to steam, which then drives the turbines. Because this is a closed-loop system, virtually nothing is emitted to the atmosphere. Moderate-temperature water is by far the more common geothermal resource, and most geothermal power plants in the future will be binary-cycle plants. (DOE)

Geothermal Power Binary cycle

To learn more about alternative energy or to gain more information on what is geothermal energy, click here.

To receive our free newsletter "Alternative Energy Resources Ezine", which will inform you of new renewable energy products and research in the field of alternative energy as well as updates to our website, please subscribe below.

Learn More

Advantages of Geothermal Energy Disadvantages of Geothermal Energy