More than 10,000 years ago was the first historical documented use of hot water for geothermal energy. This was not actually electrical output of the waters energy, but the use of its natural healing, cooking, refuge and respite. The Paleo-Indians are among the first to settle near these hot springs.
In 1921 a man by the name of John D. Grant drills a well for the intent of using the hot water to make energy to power the hot springs resort at the Geysers. This well produced 250 kilowatts of energy, enough to light the streets and buildings at the resort. This small power plant did not provide enough energy to be competitive with the other means of power and soon went out of service. It was not economically viable to power because the work in was not worth the amount of energy they were getting out.

Photo sourced from www1.eere.energy.gov
Since the 1920’s there have been many uses for the hot waters such as greenhouses, space heating, and just in the last thirty years has been used to turn steam turbines and generate larger amounts of usable power.