Geothermal energy can also be captured from heat pumps. Heat pumps tap into the heat near the Earth’s surface. This type of energy capturing can be used to heat water supplies or heat/cool buildings. Geothermal heat pumps transfer heat by pumping water or a refrigerant through pipes (also known as heat exchangers) below the Earth’s surface. During the winter months the water and refrigerants absorb heat from the Earth and deliver it to buildings and such. During summer months pumps are able to run oppositely and facilitate with cooling buildings. This requires indoor air to be removed into the heat exchanger. Additionally the heat removed from the indoor air can be used to heat water for free. Once heat is transferred the water or refrigerant is pumped back underground where the whole process begins again.

In the United States the majority of geothermal reservoirs can be found in western states, Alaska, and Hawaii. There are also only two known underground resources of steam in the United States (that are capable of running dry steam power plants).

They are the Geysers in California, and Old Faithful in Yellowstone National Park in Wyoming. However, because Yellowstone National Park is protected from development, their underground resource of steam cannot be used.

Today scientists are still searching for a technology that allows for extracting heat directly from magma, which is considered the most powerful form of geothermal energy.