Regional life cycle assessment of soybean derived biodiesel for transportation fleets

Although the life cycle environmental impacts of biofuels have been recently reported, studies that focus on specific regions and use real fleet data for the use phase are still lacking. In Pennsylvania, the Penn Security Fuels Initiative required 2% biodiesel (B2), effective on January 1, 2010, with higher blending levels required in the future if production thresholds are met. This study quantifies the environmental impacts of biodiesel blends to meet increasing regional biodiesel demand. A process life cycle model was developed using data collected from collaboration with Pennsylvania Department of Transportation. For PennDOT, both in‐state and out‐of‐state production scenarios were analyzed to estimate the possible environmental impacts of biodiesel blends. The results show that fertilizer usage in the agricultural phase, soy oil extraction and refining, feedstock and fuel transportation, and fuel combustion in the use phase are main contributors to biodiesel’s life cycle environmental impacts for all blends. Comparing biodiesels with ultra low sulfur diesel, significant environmental tradeoffs exist between global warming potential and eutrophication. For Pennsylvania, an in‐state farming and processing preference has the lowest environmental impacts for B5. However, the limited area of farmlands in Pennsylvania may not satisfy the state’s biodiesel needs with higher blending levels.