Carnegie Mellon Electricity Industry Center

2008-09 Seminars

Uncertainty and Variability in Accounting for Grid Electricity in Life Cycle Assessment

Christopher Weber, PhD
Assistant Research Professor
Civil and Environmental Engineering
Carnegie Mellon University

Abstract
The electricity sector is one of the largest sources of greenhouse gases and conventional pollutants worldwide. It has long been a focus in life cycle assessment (LCA), both as an object of LCA studies as well as a major component of the life cycle inventory of producing nearly any product or service. Despite the seemingly broad study of this important sector, considerable variation still occurs in how electricity is accounted for in LCA and greenhouse gas accounting methods. Issues of spatial and temporal averaging, as well as marginal vs. average generation mixes will be discussed, with implications for the resultant emissions factor of grid electricity. This presentation will review the status of electricity in LCA, discuss the inherent assumptions in current accounting methods, and discuss recommendations for future modeling and standard-setting.