The plant, called Ivanpah, is funded by Google, NRG, and BrightSource, a company that specializes in what’s called concentrated solar power, or CSP, a method of using focused sunlight to turn a steam generator. The technology isn’t new: a small test plant that uses mirrored troughs to heat oil-filled tubes has been running in California for 20 years. Going back further, you could point to the French inventorAgustin Mouchot, who experimented with solar powered steam engines in the 19th century, thinking we were about to run out of coal. The current batch of plants are huge—thousands of acres—and use computer-controlled mirrors to heat boilers that sit on top of towers. (You can take a virtual tour of Ivanpah’s triple-tower arrayhere.) Three giant CSP plants are scheduled to go online in the next few months, and the companies that have spent years and billions of dollars building them hope they’ll provide a valuable new source of renewable energy.
The main advantage of this type of solar plant is that it’s easy to store energy from it and save it for later use, something that will become more of an issue as we get more energy from windmills and solar panels. Energy from windmills and solar panels is cheaper, but it’s not always there when it’s needed: demand might be high on a windless or cloudy day, or low on a windy sunny one. A smarter power grid that can redirect power from renewable sources to where it’s needed can help cushion some of this streakiness, but we’re always going to need some reliable, always-available—the industry term is “dispatchable”—source of power. Right now that’s coal, gas, nuclear, and hydroelectric. The CSP industry is hoping solar can join that list, even providing power at night.