Pittsburgh is the second largest City in the Commonwealth of Pennsylvania and the County seat of Allegheny County. The City features 151 high-rise buildings, 446 bridges, two inclined railways, and a pre-revolutionary fortification. Pittsburgh is known colloquially as "the City of Bridges" and "the Steel City," and is often cited as one of America’s most livable Cities.
The City of Pittsburgh’s partnership with the Better Buildings Challenge and its goal to reduce portfolio-wide energy intensity 20% by 2020 strengthens the City's existing commitment to sustainability. In 2008, Mayor Luke Ravenstahl created the Office of Sustainability & Energy Efficiency. The Green Initiatives Trust Fund, which dedicates utility savings from bulk electricity purchases and reduced consumption to further energy efficiency projects, was established through legislation in 2008. As of June, 2012 the revolving Trust Fund has been put to work to retrofit the City-County Building with energy efficient HVAC and electrical equipment, replace 10% of the City's 40,000 streetlights with LEDs, install five solar thermal and one photovoltaic project, and purchase 25% of all electricity needs through green sources. Through the Better Building’s Challenge, the City is continuing the commitment it has made to make Pittsburgh an even more green and sustainable city.