Deep in the Mojave Desert northeast of Los Angeles the world’s largest solar thermal electric plant has starting operating three of its generating units. The Ivanpah solar energy project, developed by BrightSource Energy Co. and operated by NRG Solar, is targeted to produce 377 megawatts of power, enough to provide electricity to around 140,000 homes.
Sprawled across 3,500-acres of federal land, the $2.2 billion power plant, $1.6 billion of which was provided in U.S. government-backed loans, took six years to construct. 347,000 sun-facing mirrors called heliostats are arrayed around three 500-foot towers supporting boilers. The mirrors focus sunshine on the towers, which heats water in the boilers that in turn produces steam to turn the electricity generating turbines.
“It is like science fiction,” a traveler from Zurich, Switzerland, told a regional newspaper. “It is fascinating. I saw it being built a few years ago but didn’t know it would be so big.”
Robert Weisenmiller, chairman of the California Energy Commission, said “When this project comes fully online, California will become home to the largest solar thermal electric project in the world, creating stable jobs in a rural community and helping us to meet our goal in curbing the effects of climate change with renewable electricity.”
California wants to get a third of its electricity from renewable energy sources by 2030.
There are certain local environmental concerns yet to be fully addressed, however. Federally threatened desert tortoises have been displaced by the project and biologists are struggling to determine the fate of many of these already habitat-limited creatures. There’s also concern about bird deaths from collisions with the mirrors or burns from the suns reflection.
Solar thermal power plants can also use a lot of water. California is in the midst of a prolonged drought, the likes of which climate change will make more common.
“The drought is already forcing solar thermal power plant developers to use alternative cooling approaches to reduce water consumption,” reports the MIT Technology Review.
Solar plants like Ivanpah are taking steps to address this. Dry cooling is a new technology that can cut water consumption in these plants by 90 percent, however it is still more expensive than the conventional evaporative cooling systems used in solar thermal production. It also doesn’t work as well on very hot days, and can limit electricity production. Still, BrightSource Energy calls it “a responsible and economically-viable decision.”
At the Ivanpah solar thermal plant, the designers have oversized the cooling system so it can provide enough cooling even on hot days. The idea is that this added cost will pay off in the long term.
The stakes, just like the boiling towers, are high for this beacon of light in the desert.