Environmental Policy and Life Cycle Assessment: Implications of the Renewable Fuels Standard on Upper-Midwest Land Use

A renewable energy supply is a key component of a more sustainable society. Biomass can be an important part of a renewable energy portfolio, but in order to utilize biomass energy sustainably both good science and good policy need to be implemented effectively. This research intends to bridge the gap between Engineering and Policy studies by showing how Life Cycle Assessment (LCA) has influenced policies, and how the policy process influences LCA. We present here results of an original LCA for several regionally important feedstocks for the Upper-Midwest according to the requirements of the Renewable Fuel Standard (RFS). Additionally, an evaluation is made of the RFS according to the best practices of LCA, and recommendations are made for future policy Improvements.

The RFS is intended to stimulate biofuel production by mandating a certain amount of biofuel be blended with the U.S. transportation fuel supply each year until 2022, and setting lifecycle greenhouse gas emissions limits for those biofuels. The RFS also considers many other environmental impacts to air quality, water quality, and ecosystem health, in what LCA practitioners call an attributional analysis. Other impacts to be studied mandated by the RFS include energy security, predicted commercial fuel production, infrastructure impacts, ruraleconomic development, and food prices. These additional considerations push LCA beyond attributional analysis which only considers direct effects, towards a newer consequential analysis which also considers indirect effects.

Life cycle profiles were prepared in SimaPro 7.2 using the EcoInvent database for cellulosic ethanol produced from swithgrass, prairie grass, hybrid poplar, hybrid willow, and logging residues. Results for greenhouse gas emissions, eutrophication potential, and particulate matter emissions are presented as the basis for policy analysis. These profiles expand on LCAs performed by the EPA and others to determine what impacts the RRS may have in this region.