(41b) Comparative Life Cycle Assessment of Biofuel Produced in Two Forest Product Biorefineries

In 2007, the U.S. EPA revised the National Renewable Fuel Standard, seeking to produce 16 billion gallons of cellulosic ethanol by 2022. This legislation was motivated primarily by concerns and opportunities regarding global climate change, energy independence, and economic development. Of these 16 billion gallons, a significant portion will likely originate from forest-based feedstocks. In fact, current efforts focus on extracting fermentable sugars within existing forest product supply chains, such as kraft pulp & paper (KPP) and oriented strand board (OSB) panels. This co-production of wood products and fuel is known as an integrated forest biorefinery. Achieving a sustainable forest bioeconomy via the biorefinery models, however, will require studies that address their unique environmental benefits and challenges.

To date, life cycle assessment (LCA) has been a primary tool in guiding sustainable biofuel development. In short, LCA estimates a product's environmental impacts (i.e. resource consumption and emission outputs) from raw material extraction through production, use and end-of-life. No published studies, however, examine the life-cycle impacts of integrated KPP or OSB biorefineries.

In this study, we perform a comparative LCA of bioethanol produced within KPP and OSB biorefineries. The system boundary is from cradle-to-gate, including timber management and harvesting, feedstock extraction and panel production, and transportation. Regarding the OSB biorefinery, LCA data sources include secondary studies on timber harvesting and OSB manufacturing, laboratory-scale studies on hot water extraction of hemicellulose, and adjusted studies on bioethanol production. Results from an existing KPP LCA study by Bhander et al. (under review) will be compared to novel results for the OSB biorefinery. Preliminary results will be presented and future direction will be discussed.