Geothermal Technicians

Geothermal energy has long been used for heat, dating back to more than 10,000 years ago when the Paleo-Indians in North America used hot springs for warmth, cleansing, and healing. Underground reservoirs and hot springs are geothermal energy products. The ancient Romans used geothermal water for skin and eye disease treatment. The people of Pompeii heated buildings with geothermal water. And the ancient Japanese and Chinese, as well as other cultures, recognized the value of hot springs and reservoirs for practical and restorative purposes.

In the 1300s, French villages heated homes by using hot springs, and the first "health spa" at a natural hot springs was established in Belgium. In the 1800s, people in the United States established spas around hot springs. Scientists and engineers began to study the practical uses of geothermal energy to produce electricity. The Geothermal Energy Association (a now-defunct geothermal organization) stated that, "major district-wide heating and individual use geothermal energy projects have been in continuous, successful long-term operation at Boise, Idaho, since 1892 … and the first large-scale geothermal electricity plant opened at Larderello, Italy, in 1904."

The U.S. Department of Energy reports the following geothermal energy firsts in the United States:

• 1921: The first geothermal power plant goes into operation but does not produce enough energy to remain viable.
• 1930: The first commercial greenhouse use of geothermal energy is undertaken in Boise, Idaho.
• 1948: The first commercial building use of a groundwater heat pump occurs in Portland, Oregon.
• 1960: The first large-scale geothermal electricity-generating plant begins operations at The Geysers in Northern California.

Twenty years after the plant came online at The Geysers, several western U.S. states had geothermal power plants. By 1985, U.S. geothermal power plants produced about 2,000 megawatts (MWs) of electricity. Today, there are approximately 4.0 GWs of geothermal power online in the United States.

The United States produces more geothermal energy than any other country, yet in 2023, geothermal energy generated less than 0.4 percent of total U.S. electricity, according to the Energy Information Administration (EIA). About 21 percent of U.S. electricity is generated by renewable energy sources, including hydropower, wind, biomass, solar energy, according to the EIA.