Life cycle assessment and grid electricity: what do we know and what can we know?
The generation and distribution of electricity comprises nearly 40% of U.S. CO(2), emissions, as well as large shares of SO(2), NO(x), small particulates, and other toxins. Thus, correctly accounting for these electricity-related environmental releases is of great importance in life cycle assessment of products and processes. Unfortunately, there is no agreed-upon protocol for accounting for the environmental emissions associated with electricity, as well as significant uncertainty in the estimates. Here, we explore the limits of current knowledge about grid electricity in LCA and carbon footprinting for the U.S. electrical grid, and show that differences in standards, protocols, and reporting organizations can lead to important differences in estimates of CO(2) SO(2), and NO(x) emissions factors. We find a considerable divergence in published values for grid emissions factor in the U.S. We discuss the implications of this divergence and list recommendations for a standardized approach to accounting for air pollution emissions in life cycle assessment and policy analyses in a world with incomplete and uncertain information.
Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. clweber@andrew.cmu.edu
Christopher L
CL
Weber
Paulina
P
Jiaramillo
Joe
J
Marriott
Constantine
C
Samaras
D000397:Air Pollution / Q000706:statistics & numerical data; D058572:Carbon Footprint / Q000706:statistics & numerical data; D003247:Conservation of Natural Resources / Q000379:methods*; D004560:Electricity; D040362:Geographic Information Systems; D011210:Power Plants / Q000706:statistics & numerical data*; D014481:United States