The Mayor was up on the roof yesterday, at Riverside Correctional Facility in the Northeast. Joined by Deputy Mayor Everett Gillison and Prison Commissioner Louis Giorla, the Mayor was given a tour of the new solar hot water system being installed at Riverside.

Riverside is the central intake facility for all women who are sent to jail in Philadelphia, with an average daily population of 800. The boilers that provide hot water to the facility needed to be replaced this year.

In September, the Prison System and US Facilities, our facilities manager, first proposed an innovative option that could be added to the conventional gas-fired boilers being installed. The project team proposed an option to add a solar powered heat exchange system that will provide the primary source of hot water, using gas or oil just as a backup system.

Because the Mayor never misses a chance to remind his deputy mayors and commissioners of his goal that Philadelphia become the greenest city in America, Prison Commission Giorla approached the Office of Sustainability with the proposal.

Working with Capital Budget staffers, the project team asked for calculations about the energy savings and upfront costs associated with the solar thermal option. When those numbers came in positive, Prisons and Sustainability agreed to split the additional cost for the new technology. Less than five months later, the new system is about to go online and start saving money.

45 Solar Panels are installed on the roof of Riverside Correctional Facility, mounted in 3 rows at a 40 angle, facing south-southeast. The Solar Energy collected by the panels heats a propylene glycol solution – similar to antifreeze – in a closed system, up to 265 Fahrenheit. The heated solution is pumped through coils in well-insulated hot water tanks, and the heat exchange produces hot water for bathing, laundry, and cleaning uses by inmates and staff.

The additional cost outlay of this solar heating system is expected to pay for itself through lower energy costs in less than 9 years. The system's designed lifespan is 25 years, which means for two-thirds of its expected life the system will provide hot water at zero energy cost. And the environmental benefits begin even sooner: the reduced greenhouse gas emissions from the operation of Riverside start the day the system is turned on.

Over its useful life the solar system will save well over $1 million dollars and reduce emissions by over one million pounds of CO2.

There are a number of lessons to be learned from this little tale.

First, leadership matters. Because the Mayor has made his commitment to sustainability so visible to city workers throughout the government, innovation is starting to bubble up and tangible opportunities beginning to appear. Next on the radar screen is a large Fleet Management facility in need of a new roof. Public Property Commissioner Joan Schlotterbeck approached the Office of Sustainability about the possibility of making the project a reflective white roof or a stormwater-retaining green roof.

Second, these first-year experiments are proving to government leaders the possibilities for building sustainably. By supporting targets of investment opportunity, the Office of Sustainability plans to have a catalog of six or seven options field-tested over the next few months: solar hot water, a white roof, a more efficient motor in an air handler, automatic lighting controls, and so on. When facilities managers and capital budgeters consider these options, they'll be able to point to projects their own government colleagues have already done under the same rules and conditions they'd have to follow.

Third, we're learning how to spend money to save money. That's what smart investments do. And many of the investments will pay off faster than the Riverside solar system. Insulation and white roof spending typically pay for themselves in a year or two. That's a return on investment that can actually help us meet our current financial challenges.

Fourth, all this leadership and learning lays the foundation for even more fundamental reforms. This year, we're investing in opportunities that come to us. Next year, we plan to hold a government-wide competition for energy saving ideas and rank them according to their impact. And in the year after that, we hope to have redesigned our capital budgeting process so that energy savings are central to every investment we make and not just an add-on for some.
It's all part of the Mayor's strategy for becoming the greenest city in America. He's going to be on a lot of roofs in the coming months and years.
Mark Alan Hughes is a Senior Adviser to Mayor Nutter and the City's first Sustainability Director. Check out his other green columns here.