Solar One was the first experimental solar-thermal power tower built in California.
The facility was constructed near Barstow in the Mojave Desert and operated from 1982 to 1986. Hundreds of computer-controlled mirrors, called heliostats, reflected sunlight toward a receiver mounted on a central tower. The receiver heated oil, which transferred energy to water and produced steam for a turbine.
Solar One was a research and demonstration project rather than a conventional commercial power station. Its results helped engineers study heliostat control, receiver performance, thermal storage, and operation of central-receiver systems.
The site was later redesigned as Solar Two. That successor tested molten-salt heat transfer and storage, so Solar One and Solar Two are related but distinct facilities. Ivanpah, another California power-tower complex, began operating much later, in 2014.