Print PageLignocellulosic biomass can help fulfill escalating demands for liquid fuels and mitigate the environmental impacts of petroleum-derived fuels. Cellulosic biofuels also offer potential solutions to many socio-economic and sustainability problems caused by petroleum dependence. However, the large biorefineries which process cellulosic biomass to fuels face many logistical problems because they are fully integrated, centralized facilities in which all units of the conversion process are present in a single location. Biomass logistical problems are further exacerbated by physical characteristics of feedstocks such as low bulk density, compositional variability, seasonality and their tendency to decompose.
A potential solution to these problems might be a network of distributed processing facilities called “Regional Biomass Processing Depots” (RBPDs). In their simplest configuration these depots procure, preprocess /pretreat, densify and deliver feedstock to the biorefinery while providing a single co-product animal feed to end-users. However, the RBPDs can be configured into other, more complex setups by employing multiple technologies such as the ammonia fiber expansion pretreatment (AFEX), Leaf Protein Concentrate (LPC) extraction, leaf/stem separation, pyrolysis and anaerobic digestion, as dictated by feedstock characteristics and local conditions, to produce a variety of valuable co-products and for energy generation via synergies among these technologies.
In a previous analysis we conducted comparative life cycle assessments (LCA) between distributed and centralized processing systems combined with apportioning land area to different feedstocks, namely a corn system consisting of corn stover, grain and winter rye (double crop), and the perennial grasses, switchgrass and miscanthus, within farm-level landscapes. The farm level landscapes also include animal production operations. In this study we extend this landscape analysis to watershed- scales using more sophisticated geospatial information system tools as well as by including a wider range of feedstocks and sustainable management practices, including the use of marginal lands. On the processing side, we evaluate the energy balances and environmental impacts of advanced RBPDs and their associated transport systems by life cycle analysis (LCA) using the Gabi software.
Results/Conclusions
Through an integrated systems-wide analysis and by developing flexible models we seek the most sustainable landscape-processing-transportation arrangements for cellulosic biofuel production. We believe that greater energy and environmental benefits can be added to biofuel production by not merely aiming at improved logistics but by reimagining agricultural systems and landscapes, minimizing the challenges associated with biomass supply and its processing and by investigating multiple, potentially synergistic processing technologies and related complexities.
