Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: life cycle assessment of site specific impacts

Biofuel life cycle assessments (LCAs) generally do not address regional environmental impacts, but focus on global impacts.  Regional impacts require the location of the biorefinery be known.  Absence of location leads to an incomplete view of biofuel life cycle impacts, especially when considering impacts such as water usage that has a strong regional component.  To address this concern we have performed LCAs for four probable biorefinery locations in the Pacific Northwest.  Locations include Stanwood WA, Jefferson OR, Clarksburg CA, and Hayden ID.  The proposed biorefineries are each capable of producing 100 million gallons of bio-jet fuel per year from poplar biomass.  The feedstock demand of each biorefinery will require approximately 125,000 acres of land be converted to growing poplar trees.  Cradle to biorefinery gate LCAs are conducted for each site.  Unit process data are tailored to represent environmental and technological flows that occur within the respective watersheds of each location.  Site suitability models are used to identify the lands that could be converted to poplar production and the crops that could be displaced.  Analysis of each site includes direct and indirect land use change, poplar crop management, below ground carbon storage, and biorefinery operations.  Impacts assessed include global warming potential, fossil fuel use, water use, eutrophication, acidification, smog, and human health.   LCA results are incorporated into maps using ArcGIS and used to assess impacts specific to each region.   These results help complete the picture of life cycle environmental impacts resulting from a commercial scale biofuels industry in the Pacific Northwest.