Every five years, DVRPC performs a regional energy use and GHG emissions inventory of the Greater Philadelphia region. The inventory looks at energy use and GHG emissions associated with the residential, commercial, transportation, and other sectors of the region. The inventory does not include energy use or GHG emissions associated with the production of imports to the region, other than electricity. GHG emissions are generally reported in metric tons of carbon dioxide equivalent (CO2e) units. This measure accounts for other gases, such as methane and nitrous oxide, as well as hydrofluorocarbons and perfluorocarbons, which are emitted in smaller amounts—but are more powerful GHGs—than carbon dioxide (CO2).

Energy production source data is reported from the U.S. Environmental Protection Agency, Emissions & Generation Resource Integrated Database (eGRID). And weather trends data are from the National Oceanic & Atmospheric Administration's National Centers for Environmental Information.