1960
The Geysers — first U.S. commercial geothermal plant
Pacific Gas & Electric opened a 10-megawatt unit at The Geysers in California—the first commercial-scale U.S. geothermal development.
Historical era
Petroleum age (1950–1972)
Petroleum became the most-consumed U.S. energy source in 1950 and fueled transportation-led growth.