What Are Geothermal Technologies Used in the United States?

Geothermal power generation has the advantage of producing only a few discharges in the environment, and the source of power is continuous.

At this time, there are three major types of geothermal technology, in use in the United States: direct-use systems, the use of depth reservoirs to create electric power, and geothermal heat pumps.

Direct-use systems

In direct-use geothermal systems, a deep well is drilled into a geothermal reservoir to supply a steady stream of hot water. This water is then raised through the wall, and a mechanical piping system, a heat exchanger, and a few controls will provide the heat directly for its designated use. A disposal system then injects the cooled water back into the ground or dispossess of it in a storage pond located at the surface. Geothermal hot water is utilized for heating buildings, raising plants in greenhouses, drying crops, heating water for fish farms, or for different commercial purposes. The geothermal reservoirs appropriate for direct-use systems are extensively used on the west side of the United States.

The use of depth reservoirs to create electric power

A geothermal power plant transforms hydrothermal fluids (hot water or steam) into electrical energy. The earliest kinds of geothermal power plants have utilized the power of steam produced by deep wells, to rotate a turbine and produce electric power. Flash steam plants are the most typical geothermal power plants that are in operation today. They use incredibly hot water (above 300 degrees F) pumped under high pressure through the generation equipment located at the surface. When this hot water evaporates, the vapor on the turn will rotate the turbines to produce electric power.

Binary-cycle geothermal power plants use moderate-temperature water (100 – 300 degrees F). Water is used to evaporate a second fluid that has a much lower boiling point than water. The vapor from this second fluid is then used to rotate the turbines and produce electric energy. California, Hawaii, Nevada, and Utah are states who use geothermal power plants at this time.

Geothermal heat pumps

Geothermal heat pumps are used for heating and cooling in the residential and industrial sectors. The difference consists in the fact that underneath the surface area, the earth remains at a fairly constant temperature level through the year, warmer than the air above through the winter season, and cooler during the summertime.

A geothermal heat pump offers the following benefit: transfers the heat stored in the ground into a building through the winter, and transfers the heat into the building and back into the ground through the summer season. A heat pump must include a series of pipelines buried into the ground near the building and used to heat the water or other fluid. The heated fluid is then distributed through the pipes, to gather heat from the ground, or to distribute the heat back to the ground. Geothermal heat pumps are used in many areas of the United States.

While geothermal energy use is trusted and environmentally friendly, currently produces less than 1% of the required US electric power, even if last year, geothermal power capacity of the US grew by 5%.

We hope that geothermal power capacity of the US will be increased in the near future, and slowly, along with other green sources, will replace the existing technologies which pollute our environment.