Greenhouse Gas Methodology

Natural Gas and Propane

Natural gas and propane emissions calculations are the same throughout the country. Emissions rates are based on data published by the U.S. EPA for these fuels.  

Electricity

Greenhouse gas emissions and equivalencies are calculated using data and methodology published by the U.S. EPA. The EPA publishes several different emissions rates for the grid regions around the country. For electricity consumed on-site and derived from the local electric grid, our calculations utilize the output emissions rate (lb/MWh) which is based on the fuel/type of generation supplying the grid in the region. For the purpose of greenhouse gas emissions avoided through electricity use reductions, our calculations utilize the non-baseload emission rates. This allows for a larger avoided emissions rate (lb/MWh) since using less energy from the grid reduces the need for peaker plants which tend to be primarily carbon-based resources with a higher emissions intensity.