We calculate the carbon footprint using well-established emission factors for electricity and natural gas. According to U.S. EPA eGRID information for Dominion Virginia Power in 2007, the electricity generation process results in 1.19 pounds of CO2 emissions per kWh consumed. This 1.2 pounds of CO2 consists of a generation mix of nuclear power, coal, natural gas, and small amounts of fuel oil and hydro power. According to the U.S. Energy Information Administration, each average therm of natural gas consumed results in 11.7 pounds of CO2 emissions. The carbon footprint for each building, then, is calculated based on the amount of electricity and natural gas consumed, multiplied by the emissions factor for each fuel.