Biogenic and non-biogenic CO2 emissions are identified and tracked separately so that the contribution of the emission can be identified.
Fossil fuel use is determined by summing all fossil fuel inputs (coal, natural gas, crude oil) in terms of energy content (MJ).
Freshwater use is calculated for the life cycle of each fuel by summing all freshwater withdrawals in the life cycle
inventories (LCI).
Life cycle inventory water use data used in this study does not identify freshwater sources (groundwater, surface
water, or watersheds) and only identifies the total amount of freshwater used (water withdrawal).