In April, the City of Philadelphia unveiled its first solar photovoltaic system (above), located at PWD's Southeast Water Pollution Control Plant. The 250-kilowatt solar array consists of more than 1,000 panels covering 60,000 square feet, and its electricity will help power the energy-intensive task of water treatment. The project's total cost of $1.7 million—funded jointly by a Recovery Act Energy Efficiency and Conservation Block Grant and PWD— is expected to have a 9-year payback period and helps to achieve Mayor Michael Nutter's Greenworks goal of generating 20 percent of Philadelphia's electricity from alternative energy sources by 2015.

"PWD is proud to use clean, sustainable power generated on-site," said PWD commissioner Howard Neukrug at the solar PV installation on April 25. "Because this project was so successful, we’re planning to replicate it at other treatment plants.”

More info and a fact sheet about the solar panels can be found at the Philadelphia Recovery Office's website.

Video of the installation after the jump.