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Geothermal power is a growing part of our country’s energy mix. We want to take a moment to help you learn more about this clean, renewable energy source.
Read on to learn how geothermal energy works. Then spend some time checking out the map above, which shows locations of existing and in-development geothermal plants, over a base layer that shows geothermal heat flow potential in different parts of the country.
Conventional hydrothermal resources make up most of the current geothermal operating plants in the United States. Power generation comes from drawing heat from the fluid found naturally deep below the Earth’s surface. Steam is captured at the surface and spins a turbine, which then powers an electric generator.
A newer technology -- and one that is gaining momentum -- is Enhanced Geothermal Systems (EGS). Recent developments are making this technology more feasible and cost-effective, and we may be poised to see many new clean, renewable geothermal plants in the near future.
EGS works by injecting cold water deep into the Earth’s crust. This water flows through fissures and cracks in the basement rock, heating up considerably along its path. The ensuing steam is then pumped to the surface and, much like conventional hydrothermal, turns a turbine that powers a generator. Water is then recycled back into the Earth’s crust. Learn more about EGS with our geothermal infographic.
The geothermal sector has also seen commercial successes in low-temperature and co-produced geothermal resources --below 300°F -- to generate electricity. Co-production does this by tapping hot water from oil and gas wells and other material harvesting processes. Sometimes, low-temperature resources can be used for direct heating applications as well, such as district heating and cooling, water purification, and industrial and agricultural processes. These unconventional resources are bringing valuable returns on investment in areas of the country that have not been accessed before.
The map above allows you to learn a lot about the status of geothermal power across our country. Here we can see that areas with high heat flow potential are also areas with many operating and developing power plants. Clicking on the clusters of points will allow you to zoom into an area and see how the plants are distributed. Clicking “About the Points” and “About the Data” can give you more information on various stages of exploration and development. Learn more about how heat flow is calculated here.