The Ivanpah Valley of the Mojave Desert in California is home to spiky yucca trees, long-nosed leopard lizards, loggerhead shrikes, and a rare species of tortoise—and soon, the largest solar thermal energy plant in the world.
More than six years in the making, the Ivanpah plant is now slated to begin generating power before summer’s end. It was designed by BrightSource Energy to use more than 170,000 mirrors to focus sunlight onto boilers positioned atop three towers, which reach nearly 500 feet (150 meters) into the dry desert air. The reflected sunlight heats water in the boilers to make steam, which turns turbines to generate electricity—enough to power more than 140,000 homes.
At 377 megawatts (MW), Ivanpah’s capacity is more than double that of the Andusol, Solnava, or Extresol power stations in southern Spain, which previously were the largest in the world (150 MW each). The 1980s-era SEGS, or Solar Energy Generating System, also in the Mojave, about 100 miles southwest of Ivanpah, has a 354-MW capacity, but it is a collection of nine plants.
Viewed from above, the mirrors seem to angle their faces like enormous silvery blooms craning to the sun. At ground level, the facility stands on a 3,500-acre swath of federal land inhabited by the threatened desert tortoise (Gopherus agassizii). Once found across deserts of the American West, the species now inhabits parts of California, Utah, Arizona, and Nevada. But its numbers have dwindled: Scientists estimate some populations have declined by as much as 90 percent.