At the edge of the Salton Sea, Mark Gran surveys the clanking, hissing labyrinth of pipes that curl up from the desert in the distance. In front of him, steam belches up from a geothermal plant’s cooling towers, forming perfect puffy clouds that hang against a flawless blue sky.
"We got a lot of pots and pans," he shouts over the noise. Gran is a vice president at CalEnergy Generation, a company that’s developing geothermal power in the Imperial Valley, in Southern California.
The 16 geothermal plants that dot the Imperial Valley—10 of which are owned by CalEnergy—are among the first signs of what California hopes will become a renewable-energy boom. Researchers from the U.S. Department of Energy’s National Renewable Energy Laboratory estimate that fully exploiting a fault line beneath the Salton Sea would supply an astonishing 2300 megawatts of power, rivaling the output of a big nuclear power plant.
"This could be a great area for a renewable-energy hub," says Gran. "We just need water."
Beyond the plant, pipes reach out into the desert to bring water to the plants at the edge of the Salton Sea. For several reasons, the plants can’t just take water out of the sea. Instead, they must get their water piped in from miles away. Without that water, this plant wouldn’t make a watt. But CalEnergy isn’t the first to tap into a water supply that doesn’t naturally exist in these arid flats. A mere 20 minutes’ drive from here, the dusty brown earth gives way to a vivid jolt of green: agricultural fields that cover thousands upon thousands of hectares of desert. Flanked by bare, sand-colored mountains, bearded date palms jut from geometric green fields.
The water that fills the pipes and feeds the fields comes from the Colorado River, which has been stretched, splintered, and redirected to bring water 2300 kilometers from the Rocky Mountains, where it begins as melting snowpack. The river ends in Mexico, but a network of canals as long as the river itself sends the Colorado’s water coursing through the Imperial Valley’s sloping fields, transforming this dry place into an unlikely agricultural powerhouse.
The Colorado, however, is also a vast hydroelectric machine that supplies the Southwest with much of its energy—directly, in the form of hydropower, or indirectly, by cooling massive thermoelectric power plants. "The more energy people need, the more water you need for power plants," says Mike Hightower, an engineer at Sandia National Laboratories who analyzes the competition between water and energy needs.
The intricate relationship between water supply and electricity generation plays out dramatically in the American Southwest. The problem its residents now face is a simple one of supply and demand. The Colorado is governed by agreements collectively known as the Law of the River, which divides up the rights to the water among seven states. The main provisions, set into law in 1922, have never been updated to reflect the region’s rapid growth, and they now allocate more rights than there is water in the river. To complicate matters further, several prominent scientists predict that climate change will cause the river’s flow to shrink considerably in the coming years. Tim Barnett and David Pierce, researchers at Scripps Institution of Oceanography, in La Jolla, Calif., say that those competing claims will reach a critical point by 2021. "Water deliveries will have to be cut even beyond the most draconian measures," says Barnett.