Energy efficiency analysis has focused predominantly on reducing energy at its point of use by individual components, processes, or products. Efforts to address the energy embodied in materials through strategies and technologies that reduce raw material production -- while maintaining the function and use of materials -- offer a complementary and expansive approach to traditional energy efficiency analysis. The U.S. Department of Energy (DOE) energy analysis community currently lacks analytical tools that are appropriate for 1) estimating on a product and economy-wide basis energy-efficiency potential achieved through material efficiency strategies and 2) evaluating how these new strategies may complement existing energy-efficiency efforts.
The goal of this report is to describe a standardized analysis framework that would enable calculation of embodied and direct energy and the estimation of energy reduction potential achieved through changes in material use. The proposed framework meets this functionality by spanning the entire U.S. economy, including international trade flows; capturing material and energy use in products and services from raw material extraction to retirement; maintaining material and energy balances; and adjusting dynamically to absolute and relative changes in materials and energy use.
The framework is composed of two main elements: a dynamic hybrid input-output (IO) model and a material energy identity. The hybrid IO model defines recipes for material and energy flows in physical (e.g., British thermal units [Btu] and tons) and monetary units, and allows for dynamic adjustments to the amount of materials and energy used. The second element of the analytical framework, the material energy identity, acts as a way of identifying and organizing energy and material efficiency strategies, which are then implemented and analyzed in the hybrid IO model. The report also provides a simple example application of the proposed framework, which illustrates the concept of reducing energy use through changes to material efficiency.