Inside the World’s Largest Solar Power Plant

by Josh Sanburn,

The Desert Sunlight Solar Farm is a burst of energy in the Mojave Desert. The plant’s 8 million solar panels power about 160,000 California homes.

At the edge of the Mojave Desert, about 80 miles (130 km) east of Palm Springs, Calif., millions of midnight blue solar panels stretch to the horizon, angled toward the sky like reclining sunbathers. Here, the sun has few enemies. It shines at least 300 days of the year, bathing the more than 8 million photovoltaic (PV) panels at the Desert Sunlight Solar Farm in daylong streams of rays. All that free sunlight is converted into electricity that flows into California’s thirsty power grid, eventually helping charge iPhones in Los Angeles and switch on TVs in Sacramento.

The possibility of solar power on such a massive scale seemed remote just a decade ago. Solar was seen as a small solution to small problems, a novel way for your environmentally minded neighbor to show off his green credentials, yet too expensive to ever be economical. But that’s changed as a dramatic increase in solar-panel production–brought about by a global expansion in manufacturing capacity–has sent costs plummeting. Increasingly efficient second-generation solar technology can squeeze more energy from the sun’s rays at a lower cost, and the federal government has opened vast tracts of public land to massive for-profit ventures like Desert Sunlight.

As a result, solar power in America has officially grown up. The two largest solar power plants in the world–Desert Sunlight and Topaz Solar Farm, about 400 miles (640 km) to the west in central California–have come online in the past three months. While the first U.S. solar plant, built in 1982, generated 1 megawatt of electricity, Desert Sunlight generates 550 megawatts. Topaz produces the same amount. Together their impact on carbon emissions is equivalent to taking 130,000 cars off the road while providing 340,000 homes with clean energy.

“When the [Obama] Administration came on board, it was clear that clean energy was a priority,” says Ray Brady, manager of the National Renewable Energy Office for the Bureau of Land Management (BLM), who notes that the Department of the Interior met its target of generating 10,000 megawatts of solar energy in 2012, three years ahead of schedule. (The department has approved more than 16,000 solar megawatts.) “Desert Sunlight was very important in meeting that goal.”

But getting the location right was critical. Utility-scale solar plants need to be somewhere with year-round sun, in a space large enough to hold hundreds of thousands of solar modules but close enough to civilization to easily connect to the energy grid.

Desert Sunlight originated at a time when engineers were just figuring out how to produce solar panels on a mass scale. In the past, panels were often made using silicon, which tended to yield more energy but were expensive and difficult to mass-produce. But First Solar, which is based in Tempe, Ariz., and bought the rights to Desert Sunlight in 2010, has shied away from silicon and instead produces “thin-film” panels made with cadmium telluride, which can be cheaper than silicon but less efficient in converting sunlight into energy.

The favorable economics of thin-film PV work only if silicon remains expensive. In 2011, the price of silicon began falling rapidly, as cheap, government-subsidized Chinese PV panels flooded the market. Solyndra, a solar-energy company championing what it believed were innovative and more efficient panels made of cylindrical tubes, became a punching bag for conservatives after cheap silicon forced the company to declare bankruptcy in 2011 despite a $500 million loan guarantee from the federal government. But First Solar, which makes its solar modules in the U.S. and Malaysia, is betting on its automated, in-house production and less-expensive components to insulate it from fluctuations in the market.

Judging by its scale and location on thousands of acres of public land, Desert Sunlight seems like other sprawling, ambitious government projects before it, a Hoover Dam for the age of climate change. But the development of the plant says a lot about the new way many public-works projects are built in the U.S. today.

Desert Sunlight was the brainchild of private firm OptiSolar (later acquired by First Solar), which saw a market opportunity in helping California’s utility companies meet tough state mandates to produce a third of their energy from renewable sources by 2020. (The state currently gets 20% of its energy from renewables.)

That means the world’s largest solar farm was conceived by private business that profited from tighter state environmental regulations, with their costs underwritten in part by a federal incentive program.

It’s a model that appears to be paying off. Solar is now a $15 billion business in the U.S., employing more people than coal mining, even as costs continue to decrease.

The big question is whether projects this large are sustainable. As the price of oil and natural gas continues to drop, solar energy looks less desirable as other sources become more affordable in the short term. First Solar’s stock, for example, has dipped as oil prices have decreased.

Federal support is also drying up. A 30% federal investment tax credit will decrease to 10% by 2016. California, meanwhile, is on track to meet the state-mandated standards of 33% renewable energy by 2020. But once it does, that could reduce the incentive to continue producing solar in the state unless a tighter goal is mandated.

The energy business itself is also changing. As photovoltaic technology has gotten cheaper and energy meters have gotten smarter, it’s now possible to build a more distributed grid where electricity is generated on a smaller scale, house by house. SolarCity, for example, which designs and installs residential solar panels, has allowed individuals to drastically lower their electric bills through PV panels attached to their roofs–and often at prices that are next to nothing.

All of which means that solar power may succeed without more utility-scale projects like Desert Sunlight coming online.

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