The Solar Project

The US Department of Energy (DOE) and a consortium of US utilities built the country's first two large-scale, demonstration solar power towers in the desert near Barstow, California.

It had hundreds of large mirror assemblies, or heliostats, that track the sun, reflecting the solar energy onto a 328 ft (100 m) tall tower[3] where a black receiver absorbed the heat.

High-temperature heat transfer fluid was used to carry the energy to a boiler on the ground where the steam was used to spin a series of turbines, much like a traditional power plant.

Trade-offs involved simplicity of construction to minimize costs for high-volume manufacturing versus the need for a reliable, two-axis tracking system that could maintain focus on the tower.

Later redesigned and renamed Solar Two, it could be seen from Interstate 40 where it covered a 51 hectare (126 acre) site, not including the administration building or rail yard facilities shared with a neighboring plant.

During times of high winds, blowing dust is sometimes illuminated by the reflected sunbeams to create an unusual atmospheric phenomenon in the vicinity of the power tower.

[2] The molten salt also allowed the energy to be stored in large tanks for future use such as night time—Solar Two had sufficient capacity to continue running for up to three hours after the sun had set.

In 2001, the University of California, Davis, received funding to convert it into an air Cherenkov telescope for measuring gamma rays hitting the atmosphere.