There are currently 80 countries harnessing the geothermal reservoirs from below the earth to power their cities. And yet, many are in the dark as to how geothermal energy actually works. With 22 geothermal power plants in California alone, the United States is the leader in geothermal power output.
Aside from the large geothermal power plants, there are also heat pumps that rely on the same principles of utilizing the temperatures below the earth to heat and cool a home or business. SaveOnEnergy has put together this helpful guide about how geothermal energy works.
Geothermal power plants can generate power in three different ways depending on the type of plant. There are dry steam power plants that are the most common type of geothermal plant. These send hot steam from underground directly up into the turbines, which in turn power the generators. After the steam is used to power the turbine, it condenses and is piped back underground to be used again.
Flash steam plants pump hot water (instead of steam like the dry steam plants). The hot water gets pumped at a high pressure into a “flash tank” on the surface that is a much lower temperature. This causes the water to turn into steam. Then the steam powers a turbine and generator the same way as a dry steam above.
A binary cycle power plant is different from a dry steam or flash steam plant in that the water or steam that is pumped from underground never actually comes in direct contact with the turbines. The way these binary cycle plants work, instead is using the hot steam or water to heat a secondary liquid, which then will power the turbines and generator.
Geothermal energy can also be used to heat or cool your home with a geothermal heat pump. Closed loop systems and open loop systems can be used in your home in a variety of different ways. The closed loop systems have pipes underground in a horizontal or vertical arrangement. There are even some that go in or below a pond/lake.
Placing the pipes underground and circulating liquid through cools the liquid by utilizing the cooler temperatures from below the earth. The liquid is then passed through electric compressors and heat exchangers to heat/cool your home. In the summer, the cooler temperatures help cool a house, and in the winter, the ground below the earth is still warmer than the air.
Open loop systems work similarly except water is taken directly from a source and recycled back into that source after it has been utilized.
As a renewable natural resource, geothermal energy utilizes the almost limitless supply of heat generated from the center of the earth. The supply that is used can also be reinjected into the reservoir, making it a gift that keeps giving.
The source of the infographic: https://www.saveonenergy.com
The text is written by Vincent Nero.