The watershed-scale optimized and rearranged landscape design (WORLD) model and local biomass processing depots for sustainable biofuel production: Integrated life cycle assessments

An array of feedstock is being evaluated as potential raw material for cellulosic biofuel production. Thorough assessments are required in regional landscape settings before these feedstocks can be cultivated and sustainable management practices can be implemented. On the processing side, a potential solution to the logistical challenges of large biorefineries is provided by a network of distributed processing facilities called local biomass processing depots. A large-scale cellulosic ethanol industry is likely to emerge soon in the United States. We have the opportunity to influence the sustainability of this emerging industry. The watershed-scale optimized and rearranged landscape design (WORLD) model estimates land allocations for different cellulosic feedstocks at biorefinery scale without displacing current animal nutrition requirements. This model also incorporates a network of the aforementioned depots. An integrated life cycle assessment is then conducted over the unified system of optimized feedstock production, processing, and associated transport operations to evaluate net energy yields (NEYs) and environmental impacts. A sustainability assessment was conducted in a nine-county region of Michigan for the categories of cellulosic ethanol production, soil characteristics, water quality, and greenhouse gas (GHG) emissions. Making significant changes such as introducing perennial grasses, riparian buffers and double crops in current landscapes provides the largest absolute NEYs of about 53 GJ/ha while also attaining 120% gains in soil organic carbon, 103% lower nitrogen leaching, and 68% reductions in net GHG emissions (compared to a baseline of current conventional landscapes). Interestingly, minimizing certain environmental impacts also provides greater NEYs. (c) 2013 Society of Chemical Industry and John Wiley & Sons, Ltd