There is growing interest in the development of tools and methods for calculating the supply chain energy and carbon "footprints” associated with products and services. Much of the activity has been in response to "low carbon" product reporting mandates by large global retailers, such as Wal-Mart and Tesco. However, relatively little attention has been paid to the development of models that allow decision makers to assess realistic opportunities for reducing such footprints once they've been established. This presentation will provide an overview of a new supply chain energy use and greenhouse gas (GHG) emissions modeling methodology, which characterizes the key underlying technologies and processes that contribute to the energy and carbon footprints of a variety products and services. The approach allows for both environmental and economic assessment of supply chain technology and process improvements, which can help lead to targeted and better-informed supply chain energy efficiency and GHG mitigation strategies. The methodology will be demonstrated using a U.S. case study.