There's gotta be a better place: That's become the mantra of environmentalists protesting wind and solar projects on undeveloped public lands. And it's the argument behind a movement to develop already-sullied places instead -- decommissioned landfills, abandoned mines and the like.

The idea isn't new. The Environmental Protection Agency has endorsed it in some form since at least 2003, estimating that more than 11,000 contaminated sites nationwide are suitable. A handful of built projects prove that brownfields can turn green, but the concept has yet to be broadly implemented. "There was no driver," says Blair Loftis, alternative and renewable energy director for Kleinfelder, a San Diego-based engineering firm.

Kleinfelder hopes to fill that void, styling itself as a matchmaker between mining and solar companies. And as conflicts intensify over planting wind turbines in sage grouse habitat and fragmenting the Mojave Desert with sprawling solar farms, the notion is gaining steam.

It can be "the path of least resistance from a regulatory perspective," Loftis says, and contaminated lands boast "gigawatts of opportunity."

Loftis focuses on putting solar arrays on tailings piles, which he says offer thousands of flat acres close to existing power lines. (Kleinfelder's currently working with five undisclosed mines.) And since mines and their waste tend to be on privately owned land, projects can often be developed without cumbersome federal and public environmental reviews, calming investors' nerves.

Obstacles remain, but developers are finding ways around them. At some brownfield wind and solar farms, they've arranged to leave legal liabilities with the landowner. And regulatory agencies have so far approved changes in land use.

Rocky Mountain Power's plan to build a 237-megawatt wind farm on a reclaimed coal mine in windy Converse County, Wyo., "created another level of scrutiny on a piece of land where the company already had requirements (to recover it)," says company spokesman Jeff Hymas.  But state agencies "were willing to work with us." Now, he says, "It's really considered the crown jewel of all our wind farms."