U.S. transportation models forecasting greenhouse gas emissions: an evaluation from a user’s perspective

This paper briefly describes and evaluates some of the more important and frequently used models to estimate greenhouse gas emissions by a number of U.S. government agencies. Among the models covered are: National Energy Modeling System (NEMS); MARKAL-MACRO; MiniCAM; Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model; and Transitional Alternative Fuels and Vehicles (TAFV) Model. These models have been used by the U.S. Congress and federal agencies to assess U.S. strategies to meet the Kyoto Accord, which would require the United States to maintain U.S. carbon emissions at 7% below 1990 levels between 2008 and 2012. In this paper, each model is described and its capabilities and limitations highlighted. Model perspectives are provided from a user's viewpoint, so that potential users will have a full understanding of the capabilities of these models and the resources needed to build, update, and maintain them.