Geothermal energy is a renewable energy source that harnesses energy from the heat in the core of the earth. This heat is either accessible through the ground or through the ground water. Geothermal energy can be used for bathing, heating buildings, and generating electricity.
On a commercial scale, geothermal energy is captured via power plants that generate steam to spin turbines and create electricity for large-scale use. Geothermal power plants produce electricity consistently, 24 hours a day, 7 days a week. At the household level, homeowners can invest in ground source heat pumps to capture geothermal energy. These renewable energy solutions produce no greenhouse gas emissions and save money on utility and district-scale energy for consumers over time, making them a key component of the decarbonized grid of the future.
In power plants, utility-scale method wells are drilled deep into the earth to pump hot water to the surface at high pressure. At the surface, the pressure is dropped, causing the water to turn into steam. The steam spins a turbine connected to a generator, producing electricity. In a cooling tower, the steam condenses back into water, which is then pumped back into the earth to begin the process anew.
Geothermal power plants are usually found in areas with hot springs, geysers, or volcanic activity. In the United States, they are primarily situated in the Western states and Hawaii, with California generating the most electricity from this renewable source.
At the residential level, ground source heat pumps can heat and cool houses, and even heat swimming pools. In this setting, heat is transferred by pumping water or a refrigerant through a loop of vertical or horizontal pipes buried just below ground level, where the temperature is constant. During the winter, the liquid absorbs warmth from the Earth, and it is pumped to the structure above. The liquid cools following the heat transfer and is pumped back underground, repeating the process. In warm weather, the process runs in reverse. Ground-source heat pumps are fueled by electricity, a more environmentally friendly heating and cooling system than fossil fuel-based technology, depending upon how that electricity is powered. If powered by renewables, the electricity is emissions-free.
When embedded in the fuel mix, heat pumps are extremely beneficial because they do not require grid lines to deliver energy to buildings. This is because the energy is produced underground, below the consumer, and delivered directly to them. The U.S. Department of Energy has concluded that if the nation utilizes heat pumps to their full capacity, we could “avoid as much as 43,500 miles of new grid transmission lines by 2050”.
For climates with moderate heating and cooling needs, you can install heat pumps without geothermal (and, therefore, without digging into the ground). Air-source heat pumps move heat, in the winter, from the cool outdoors into your home and, in the heat of the summer, move heat from your home into the outdoors. A vastly cheaper way to heat and cool. Much more about air source heat pumps here.
Geothermal energy works in most climates and can offer up to a 70% reduction in heating costs and a 50% decrease in cooling costs. Up-front installation costs are high, but systems generally pay for themselves in five to seven years and eventually cost less over time than fossil fuel systems.
However, ground-source heat pumps can require alterations to the landscape with drilling into the ground. Therefore, it is essential, and sometimes difficult, to locate a safe, open landscape to house the pipes that will be drilled into the ground for these systems. Additionally, open-loop geothermal systems, while uncommon, are not recommended as they can contaminate groundwater.
As of 2026, geothermal energy accounts for roughly 0.4% of total U.S. utility-scale electricity generation, producing approximately 16 billion kilowatt-hours (BkWh) annually.
Geothermal energy has a massive technical potential, capable of meeting global electricity demand many times over. Next-generation techniques like Enhanced Geothermal Systems (EGS) make it globally viable rather than restricted to tectonic hot spots, with the U.S. Department of Energy targeting over 8% of U.S. electricity by 2050
A Canadian company recently sent us a heat pump glossary which you might find useful. Visual of current geothermal market from https://docs.nlr.gov/docs/fy26osti/91898.pdf
CREDIT: EIA
