Water consumption and water quality continue to be key factors affecting environmental sustainability in biofuel production. This review covers the findings from biofuel water analyses published over the past 2 years to underscore the progress made, and to highlight advancements in understanding the interactions among increased production and water demand, water resource availability, and potential changes in water quality. We focus on two key areas: water footprint assessment and watershed modeling. Results revealed that miscanthus-, switchgrass-, and forest wood-based biofuels all have promising blue and grey water footprints. Alternative water resources have been explored for algae production, and challenges remain. A most noticeable improvement in the analysis of life-cycle water consumption is the adoption of geospatial analysis and watershed modeling to generate a spatially explicit water footprint at a finer scale (e.g., multi-state region, state, and county scales) to address the impacts of land use change and climate on the water footprint in a landscape with a mixed biofuel feedstock.
Water sustainability is an integral part of the environmental sustainability. Water use, water quality, and the demand on water resource for bioenergy production can have potential impacts to food, feed, and fiber production and to our social well-being. With the support from United State Department of Energy, Argonne National Laboratory is developing a life cycle water use assessment tool for biofuels production at the national scale with multiple spatial resolutions. This open-access web-based model – WATER (Water Assessment Tool for Energy Resources) – ties hydrologic cycle to energy production supply chain with a focus on feedstock production and biorefinery conversion stages. The model employs water footprint accounting to quantify the consumption of blue water, green water, and grey water in the fuel production at regional, state, and county resolution for the entire United States. Direct and indirect water uses are considered, which includes electricity generation and petroleum fuel and natural gas production. It is capable of simulating future climate scenarios. Currently, WATER includes biofuel produced from corn grain, corn stover, switchgrass, miscanthus, and soybean. The model is designed to allow for evaluation of production pathways at the region where the specific feedstock grown; for comparison of biorefinery locations based on water sustainability metric, and for analysis of the interplay of policy, feedstock, pathway, and location factors and the trade-offs among environmental, economic, and social impacts.