The massive solar plant nearing completion in the California’s Mojave desert doesn’t look like the solar plants you might be used to seeing. It has no solar panels, for one thing. Instead, it has mirrors-300,000 of them-all arrayed in rings around three giant towers. The mirrors reflect sunlight onto vats of water sitting on top of the towers, heating them to 500 degrees and powering a steam turbine, providing enough energy for 140,000 homes. When it goes online at the end of the year, it will be one of the biggest solar plants in the world. But the technology at its heart is relatively simple: mirrors, water boilers, and steam turbines.

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 inventor Agustin Mouchot, who experimented with solar powered steam engines in the 19th century, thinking we were about to run out of coal. […]