Solar energy is abundant, non-polluting, and does not emit greenhouse gases. It can be applied at both large and small term scales. Smaller distributed solar electricity generation by individual homes, institutions or businesses is an economic possibility because New York has adopted “net metering,” which allows excess electricity generated on sunny days to flow back into the electric grid, with credit or payment from the utility company for the power generated.

According to a test conducted in July 2011, over TWO THIRDS of New York City’s rooftops are suitable for solar panels that would create a joint network capable of providing about 50% of the needs at peak times. This was conducted by a series of flights over the city with a plane equipped with a laser system known as Lidar.

Over all, the images show that 66.4 percent of the city’s buildings have roof space suitable for solar panels, said the CUNY team, which developed the map in partnership with the city and the federal Department of Energy. The rooftops could generate up to 5,847 megawatts from hundreds of thousands of buildings, the team said, compared with the negligible 6.5 megawatts yielded now from about 400 installations.

At these output levels, it could produce about 15% of the city’s energy, as opposed to less than 1% currently.