Greenhouse Gas Calculator
NAPA's Greenhouse Gas Calculator, revised in 2012 and currently under beta testing, calculates greenhouse gas emissions related to asphalt pavement manufacturing in a gate-to-gate analysis. The user-friendly interface provides drop-down lists of typical fuels that are linked to greenhouse gas emission factors, expressed as carbon dioxide equivalents (CO2e), the universal measure of greenhouse gas emissions.
The Calculator provides inputs for three separate fuels used by a rotary dryer plus three additional fuels used inside the facility by equipment, including vehicles. A final category addresses CO2e attributed to electrical use, with unique factors for each state. Fuel used for onsite power generation should also be included. Generally, the more fuel combusted or burned, the more CO2-equivalent gases are emitted.
This beta update of the Greenhouse Gas Calculator adds emission offset credits for those fuels and activities that either reduce the amount of CO2e released or that sequester CO2. Credits are calculated for plant-based bio-fuels, transportation credits for waste derived fuels like recycled fuel oil, and cradle to gate credits for recycled raw materials like RAP and shingles. Credits are also calculated for reducing mix temperatures using warm mix asphalt technologies, based on user defined mix temperature.
The Greenhouse Gas Calculator was developed under the leadership of NAPA's Environmental Committee. Refinements and enhancements will be made as need arises based on user feedback. If you have suggestions for enhancements, or questions regarding underlying algorithms, please contact Howard Marks, NAPA Director of Environmental Affairs.