Clean Energy’s statements concerning the impacts of renewable natural gas (RNG) on carbon/greenhouse gas emissions are based on using GREET Life Cycle Assessment (LCA) as a basis for greenhouse gas modeling. Like the modeling used in the California Air Resource Board’s (CARB) Low Carbon Fuel Standard (LCFS), this modeling compares the carbon intensity of fossil diesel fuel with the carbon intensity of RNG fuel derived from dairy manure. Carbon intensities from CARB’s LCFS program for different pathways and feedstocks are calculated and verified by organizations that are accredited verification bodies or accredited individual verifiers who can verify such LCA’s.
Clean Energy annually creates a greenhouse gas inventory in line with the GHG Protocol, displaying material GHG emissions within its value chain in Scope 1, 2 and 3. As it relates to the use of conventional natural gas, renewable natural gas, or hydrogen as a fuel, emission reductions can refer to either greenhouse gases or criteria pollutants. For GHGs, the emissions can be expressed by mass of the greenhouse gas (CO2, CH4, N2O, etc) or by using a global warming potential (GWP) adjusted factor in line with the latest UN IPCC which allows for the expression of the greenhouse gas in terms of a mass of CO2e or carbon dioxide equivalent. Criteria pollutant can encompass several different emissions including NOx, SOx, Particulate Matter (PM1.0, PM2.5), CO, VOC’s, etc. Currently Clean Energy does not have 3rd party verification on its GHG Inventory, but is working towards this in the future.
For additional information, please see our sustainability report available here: https://www.cleanenergyfuels.com/sustainability
