Life Cycle Assessment (LCA) of biodiesel from soybeans is a cradle to grave evaluation of energy and environmental issues associated with producing, harvesting, and transporting soybeans, converting the soybeans into biodiesel, and distributing and using the biodiesel in motor vehicles. Soybean biodiesel LCAs frequently include an assessment of diesel fuel, the petroleum derived product that biodiesel will displace, as a means to compare the two products.
Biodiesel production in the U.S. is currently limited but is increasing. Most biodiesel used today is added to diesel fuel using a mixture of 20% biodiesel and 80% petroleum-derived diesel (B20).
Recent LCAs of biodiesel from soybeans found that B20 reduced the amount of petroleum used, other fossil fuels used, and the amount of greenhouse gas emissions compared to using diesel fuel, but found mixed results with respect to emissions of nitrogen compounds.