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November 05, 2015

Philly's biggest polluters are its buildings, report says

Drexel University finds 60 percent of city's emissions come from buildings' energy use

Environment Pollution
Drexel University Thom Carroll/for PhillyVoice

Drexel University

The biggest source of greenhouse gases in Philadelphia isn't an exhaust-belching car, a new report says. It's the office building that driver works in.

A Drexel University report released Wednesday and written for the Mayor's Office of Sustainability found that energy-gobbling buildings account for 60 percent of Philly's carbon footprint.

That's three times more than the next-biggest source of greenhouse gas emissions: Cars, trucks and buses, which emit 19 percent of the city's gases.

The solution: Retrofit large buildings like hospitals, schools, office buildings and supermarkets so they waste less energy. Invest in technologies like better insulation, motion-sensor lights, electrical heat pumps and roofs painted white to reflect sunlight.

Large establishments would ultimately save money because the retrofits would result in lower utility bills. However, the authors acknowledged that trying to overhaul residential housing would be much less cost-effective.

They recommend focusing instead on providing those homes with electricity from renewable-energy sources. Philadelphia gets 56 percent of its energy from coal or natural gas and 40 percent from nuclear power, but almost nothing from solar or wind. Other recommendations in the report include using electric buses for public transportation, while encouraging people to drive less or buy electric cars.

The ultimate goal: an 80 percent reduction in emissions within 35 years. Right now, Philly emits 21 million tons of carbon dioxide per year, or 13.7 tons per person, which is actually far less than the U.S. average.

“Cities, as population and economic centers, are responsible for generating about three-quarters of the emissions that are driving global warming,” said Joseph Hughes, director of Drexel's Institute for Energy and the Environment. “But what makes cities a big part of the problem also makes them a big part of the solution — implementing large-scale de-carbonization strategies in metropolitan areas would have a tremendously beneficial effect on a global scale.”

So how much would all this cost? The authors estimated the price of different sustainability measures in terms of how much it would take to avert 1 ton of CO2, on average.

• Retrofitting buildings in every sector: $55/ton

• Retrofitting just office buildings: $6/ton

• Switching to renewable sources of electricity: $23/ton

• Switching to hybrid cars: $90/ton

Saving the planet, though? That's priceless.

Read the study's findings here.