The massive Ivanpah Solar Electric Generating System in California’s Mojave Desert will eventually generate 370 megawatts, a 60 percent increase in US solar-power capacity. Scheduled for completion in 2013 by energy company BrightSource, the 5½ square miles of mirrors will reflect the sun’s heat at water towers, producing steam to spin turbines (natural gas will serve as cloudy-day backup). Ivanpah is supposed to help California generate a third of its electricity from renewables by 2020. Awesome, right?

After all, the Mojave is perfect for producing solar energy (lots of photons). But building there has costs—costs that environmental groups and others say aren’t worth it. (They’ve filed suits to stop the project.) Do cultural and ecological concerns trump fighting climate change? Here’s a look at the planned facility—and its ledger.