Geothermal Energy Overview
Geothermal energy is a renewable resource that is created from the heat within the earth. Geothermal energy is used for both heating and cooling applications. Geothermal energy is the smallest source of renewable energy in the United States after biomass, wind energy, hydroelectric, and solar power. It makes up just 0.4 percent of electricity generated in the country.
Want to learn more about geothermal energy in the United States? In this article, we’ll explain how geothermal energy works, what it’s used for, how much geothermal energy costs, and more.
How geothermal energy works
Geothermal energy is generated using the heat within the earth. There are three things that are needed to generate geothermal energy:
- Sufficient fluid that either exists naturally or is pumped into the reservoir
- The heat from within the earth, which varies based on location
- Permeability that allows the fluid to come in contact with the heated rock
Geothermal is then created at power plants that use the steam produced by the reservoirs to produce electricity. There are three different types of technologies that can be used at geothermal power plants: dry steam power plants, flash steam power plants, and binary cycle power plants.
The geothermal energy that’s produced can then be used not only for electricity but also for heating and cooling.
Types of geothermal energy plants
Geothermal energy for your home
Geothermal energy is used for two primary purposes: electricity generation and heating and cooling. And depending on where you live, geothermal energy might be part of how you power electricity or heat in your home.
As we mentioned earlier, geothermal energy generation requires a few specific characteristics that aren’t available everywhere. Depending on where you live, there may be geothermal power plants operating nearby, in which case you may already benefit from this renewable resource. But it’s also possible to install your own geothermal heat pump (GHP) system to power your home or business.
Geothermal heat pumps
Powering your home with a geothermal heat pump allows you to harness the temperatures below the surface of the earth to heat or cool a structure. Even though the temperatures above ground fluctuate during the seasons throughout the years, the temperature below the surface remains consistent between 50˚F – 60˚F year round.
There are four types of pumps, three closed-loop systems and open-loop systems. Each depends on the type of soil, climate conditions and land available.
Cost of geothermal energy
There is a cost investment required to create geothermal energy because of the well drilling and pipeline construction required. According to the U.S. Department of Energy, the initial cost to build this type of power plant is around $2,500 per installed kWh.
The cost of residential geothermal heat pumps run between $12,000 and $30,000. While it’s a significant cost investment, it can also result in energy savings in the long run. Investing in a residential GHP also lowers your home’s carbon footprint over time.
Where is geothermal energy thriving?
Geothermal energy is the smallest source of renewable energy for the United States. In 2020, there were geothermal power plants in seven states, which produced a combined 17 billion kilowatt-hours of geothermal energy.
The states in the U.S. that produce geothermal energy are:
|State||% of U.S. geothermal energy generation|
FAQs about geothermal energy
Is geothermal energy a renewable power source?
Yes, geothermal energy is a renewable power source. It is generated using the heat within the earth, which is virtually unlimited. Geothermal energy is also considered a greener energy source compared to fossil fuels because it does not emit carbon dioxide at high levels.
Can geothermal energy power my home?
Depending on where you live, geothermal energy may already power your home. If you don’t live in a state with geothermal energy production, you can buy a GHP system to generate electricity for your home.
Where are the largest geothermal reservoirs located?
California is home to most of the geothermal electricity generation, producing more than 70 percent of the nation’s geothermal power. California’s Geysers Geothermal Complex is the world’s largest geothermal installation.
What are the types of geothermal power plants?
There are three types of geothermal power plants: dry steam power plants, flash steam power plants, and binary cycle power plants. You can read more about the types of geothermal power plants in our geothermal guide.