(704a) Key Ingredients and Co-Products in Biofuel Life Cycle Analysis

In many cases, life cycle analyses (LCA) of biofuels have treated key ingredients and co-products less rigorously than feedstocks and fuel products.  Key ingredients and co-products, however, can significantly impact LCA results and merit attention.  For example, we have recently examined the contribution of enzymes to the life cycle energy consumption and greenhouse gas (GHG) emissions of corn and cellulosic ethanol with Argonne National Laboratory’s Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model.  We estimate that the contribution to farm-to-pump GHG emissions in the case of corn ethanol is approximately 1%.  In the case of cellulosic ethanol, this contribution is much higher (up to 20%) because enzymes are consumed at a much higher rate.  We have also added new data to GREET for the production of yeast and determined that it can contribute up to 11% of farm-to-pump emissions for cellulosic ethanol.  

 Additionally, we examine key co-products from biofuel production with a focus on biochar, which has not received rigorous treatment in previous biofuel LCAs.  We discuss the properties of biochar including GHG mitigation, yield increase, and fertilizer offsets and how these properties can be incorporated into LCAs of biofuels that produce biochar as a co-product.