The history of geothermal energy use traces back tens of thousands of years around the globe. In times pre-dating modern western civilization, indigenous peoples used hot water from springs for cooking, cleaning, and bathing. These springs served as a source of warmth and their minerals as a source of healing. Archeological evidence shows that the first human use of geothermal resources in North America occurred more than 10,000 years ago with the settlement of Paleo-Indians around hot springs.

Modern use of geothermal energy is characterized by increasingly more organized commercial and industrial ventures from spas and resorts in the early 1800s to the eventual development of electricity production and geothermal heat pumps. Within the next twenty years, more resorts and spas of increasing size would grow up around such springs.

In 1892, the world's first district heating came online in Boise, Idaho, eventually growing to serve 200 homes and 40 downtown businesses. Although this system was unique for 70 years, there are now 17 geothermal district heating systems in the United States and dozens more around the world. In Iceland, the entire capital city of Reykjavik is powered by the geothermal energy from the North Atlantic Oceanic Ridge below the island.

In the early 1900s, the first instance of geothermal electric power emerged. In Italy, Prince Piero Ginori Conti invented the first geothermal power plant in 1904 at the Larderello dry steam field and it is still in operation today. The first geothermal electricity plants in the United States were operated in 1960 at The Geysers in Sonoma County, California. They produced 11 megawatts (MW) of net power and operated successfully for more than 30 years. Today, 69 generating facilities are in operation at 18 sites around the country.

Throughout the 1970s, government backing through legislation, grants, and the actions of agencies like the Department of Energy furthered research, development, and continued acceptance of geothermal electrical power into the electricity producing mainstream. Work in the 1970s laid the foundation for actualization of more advanced types of geothermal steam production in the 1980s from flash steam to binary vapor cycles. Net electrical output of these plants reached 50MW by the end of the decade. Progress continued in the 1990s as the Department of Energy increased its efforts to promote the use of geothermal energy for electricity generation as well as space and process heating. By the mid-90s, the DOE identified over 9000 thermal wells and springs and 271 communities connected to geothermal energy.

Modern non-electrical use of geothermal energy continues. For instance, beginning in the 1960’s the Maoris of New Zealand have used geothermal energy for cooking. France and many other European Union nations are using geothermally heated water to heat thousands of homes.

Brief review of early geothermal energy efforts in Iceland, especially focusing on the digging of Thvottalaugar (washing pools) around the capital city of Reykjavik.

Geothermal Energy and Other Distinctive Energy Sources       
Milestones in geothermal power intertwined with relevant historical instances in thermodynamics, engineering, drilling, and electrical power production. Short essay covering low tech to high tech uses, including a drilling and mining angle.

Modern Heating and Cooling for Historic Structures Slide Show Presentation 
Copley Square in Boston, Massachusetts.Flash slideshow of how small-scale geothermal power is helping preserve the historic integrity of landmark buildings while giving them the comfort and convenience of modern heating and cooling systems. One such project was the Trinity Church in Boston Massachusetts.

​History of Geothermal Power