Tuesday, May 3, 2011
The logistical and feedstock supply challenges that fully integrated, centralized biorefineries currently face can potentially be dealt with by a network of distributed processing facilities called “Regional Biomass Processing Depots” (RBPDs). These depots procure, pre-process /pre-treat, densify and deliver feedstock to the biorefinery and return by-products such as animal feed to end-users. In a previous preliminary analysis, we conducted comparative life cycle assessments between distributed and centralized processing systems combined with apportioning land area to different feedstocks within farm-level landscapes. We allotted varying acreages to a corn system (corn grain, stover and a winter double crop rye) and two perennial grasses, switchgrass and miscanthus. In this study we aim to extend this mixed feedstock landscape analysis to watershed- scales using more sophisticated geospatial information system tools while including a wider range of feedstocks such as agricultural residues, double crops, perennial grasses, native prairies and woody biomass into the landscapes. We then intend to combine these landscapes with RBPDs varying in complexity. The level of complexity of RBPDs can be altered by either incorporating a single technology such as only pre-treatment in a simple set-up or by using multiple technologies such as pre-treatment, liquid protein concentrate extraction, anaerobic digestion, and so on in an advanced set-up. Through this integrated systems-wide analysis we seek the most sustainable landscape-processing-transportation arrangements based on energy returns on investment as well as on environmental impacts such as acidification and eutrophication potential, water and soil quality and green house gas emissions.