New York City's mayor Michael Bloomberg puts birds on things, if by "birds" you mean solar panels and "things" you mean the city’s myriad defunct landfills. The so-called greening of brownfields is a nationwide trend, since landfills and other plots of ruined land close to or even within cities are often not suitable for other applications.

You can't build houses on a capped landfill, and short of turning them into parks — an expensive and, to some people, kinda gross proposition — they have few applications. Solar panel installations, however, tend to be light-weight and require nothing more than open space. The closer renewable power plants are to the users of their electricity, the more efficient they are, because losses from transmission of their electricity are minimized. So urban brownfields that would otherwise go unused are uniquely suited to hosting large arrays of solar panels.

It's all part of the city's PlaNYC, an ambitious agenda to reduce the city's greenhouse gas emissions 30 percent by 2012. The plan's 100-plus programs also include an energy efficiency corporation for helping building owners finance energy conservation measures, and a phase-out of the dirtiest heating oils.

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