Biofuel production potential in the southwestern U.S

Background/Question/Methods

Many states are enacting alternative energy mandates that specify percentages of supplied energy that must come from alternative energy sources in the coming decades. In order to meet these future alternative energy quotas, biofuels will likely become an increasingly important part of energy portfolios at local, state, and national levels. Currently in this country, most biofuels feedstocks are grown on productive agricultural lands, with the potential to reallocate farmland away from food production. However, there is increasing recognition that feedstocks grown on “marginal” lands could play a critical role in meeting future biofuel demand without jeopardizing food security. In particular, there is growing interest from governmental, academic, and private entities in exploring the vast public lands of the southwestern U.S. for biofuel production. Despite this interest, very little is known about the ecosystem impacts of biofuel production in the Southwest, and the potential benefits and risks of have yet to be quantitatively examined.

Results/Conclusions

Here we explore the viability, large-scale production potential, and ecological impacts of both current (e.g., switchgrass, canola) and next-generation (e.g., algae) biofuels feedstocks in the Southwest. We discuss modeling and on the ground approaches to assessing the likelihood that arid and semi-arid biofuels production on marginal lands would offer viable energy sources, compare different biofuels crops, and consider opportunities for smaller-scale, local biofuel production from woody biomass that may have co-benefits with restoration or fire-prevention objectives. In these ecosystems, major consideration needs to be given to the availability of water resources, which are likely to ultimately determine the sustainability of any southwestern biofuels production. Additionally, land use change could alter dust flux and nutrient cycling in these systems, with large-scale consequences, and could temper the climate-change mitigation provided by alternative energy use. However, the high solar energy inputs, high availability of large tracts of marginal public lands, and the low carbon stocks of these landscapes make the Southwest an important region in considerations of the nation's diversifying alternative-energy portfolio.