Some might say Mayor Nutter's budget-cutting is putting him out on a limb. Today, he went up on the roof, unveiling a new solar water-heating system at the  Riverside Correctional Facility.

It's being touted as the first large urban jail in the country to install such a system. The project will provide energy savings of 20-25 percent annually over the anticipated 25-year life of the system, saving an estimated $1.1 million and one million pounds of carbon emissions.

It all began when the prison started having trouble with its water heaters. US Facilities, Inc., the contracted facilities management provider for the jail, came up with the solar solution. And, apparently, it was all done without any interruption of water service to the staff or the 800 inmates.

According to a city statement, the system replaces five-year-old conventionally-fired boilers with 15 insulated water storage tanks that are heated by an indirect circulation system. Food grade propylene glycol – heated by 45 roof-top solar panels – is pumped in a closed coil through the storage tanks.

Funding for the project comes from the Prison System's budget ($400,000 spread over three years), with supplemental funding from the Mayor's Office of Sustainability ($265,000). Riverside is the central intake facility for all women who are incarcerated in Philadelphia.