Similarly, Boise Idaho has used hot springs for home heating since the 1890's, and France, Hungary, and New Zealand use underground hot water for domestic and industrial purposes. Currently, at least eight countries generate geothermal electricity. The Italians built the first such plant in 1904, with a power output of 350 million watts. The world's largest plant, at the Geysers in California, generates enough electricity to power San Francisco. A 1975 study by the US Geological Survey estimates that known geothermal resources in the US could produce 140,000 watts of electricity over the next 30 years, or about the same power as 140 nuclear plants.
Geothermal energy is a vast non-polluting source of heat and electricity.
Much of the technology is already known and its further development will play an important role in the transition to a renewable energy future.