Transportation fuels generate greenhouse gas (GHG) and air pollution emissions across their entire life cycle, not just when they leave the tailpipe. The life cycle emissions are referred to as the “well-to-wheels” emissions (or “seed-to-wheels” by the biofuel industry). Modeling these life cycle GHG emissions is challenging because there are numerous steps, inputs, and resources involved in making transportation fuels. But these modeling efforts are critical because it is important to compare the impacts of various fuels. Scientists at Argonne National Labs developed the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model to respond to this challenge. The model helps assign GHG or “carbon” intensity values for almost all fuels including ethanol, biodiesel, gasoline, or natural gas made from various feedstock such as corn, sugarcane, algae, and/or fossil fuels. It also allows users to model the GHGs from various vehicle and fuel combinations. EcoShift uses GREET to conduct life cycle assessments for clients who are interested in the “well-to-pump” carbon intensity (usually for fuel producers as required by various regulatory agencies) or the “well-to-wheels” carbon intensity (usually for policy makers, automobile manufacturers, or automobile fleet owners). The US Environmental Protection Agency and California Air Resources Board are just two regulatory agencies that use GREET to assign carbon intensity values to transportation fuels for the purposes of emissions trading schemes and to qualify as renewable or advanced biofuels. As low carbon fuel standards evolve, GREET will be a critical for demonstrating regulatory compliance. For more information, read about Alternative Fuels LCA, see our service offering on transportation fuels, or contact us.