(226a) Reimagining Agriculture to Accommodate Large Scale Energy Production | AIChE

(226a) Reimagining Agriculture to Accommodate Large Scale Energy Production


Dale, B. E. - Presenter, Great Lakes Bioenergy Center, Michigan State University
Richard, T. L. - Presenter, Pennsylvania State University
Anex, R. P. - Presenter, Iowa State University
Laser, M. - Presenter, Dartmouth College
Bals, B. D. - Presenter, Michigan State University

Central to the debate over the efficacy of biofuels is the question of whether plants could ever be grown, harvested, and converted to fuels in quantities sufficient to meet a substantial fraction of mobility demand while feeding the world, preserving wildlife habitat and environmental quality, and achieving large reductions in greenhouse gas emissions. Writing in 2007, Lynd et al. observed that estimates for the potential energy contribution of biomass exhibit a bimodal distribution such that either a very small or very large energy supply role is anticipated. Widely disparate assessments of the feasibility and desirability of large scale biofuel production have continued to appear since that time. Reaching reconciliation on this key point is needed to avoid over-supporting undeserving options, under-supporting deserving options, or - in light of the broad range of biomass energy feedstocks and technologies ? both.

There is increasing recognition that achieving a sustainable and secure energy future requires large changes to the non-sustainable and insecure present, and that the multi-faceted, systemic energy challenges we face require multi-faceted systemic solutions (Friedman, 2008). Biofuels are a case in point. To a substantial degree, the starkly different conclusions reached by different analysts on the biomass supply issue reflect different expectations with respect to the world's willingness or capacity to innovate and change rather than hard, physical constraints (Lynd et al., 2007).

Although land use and other practices associated with food production are commonly assumed to remain unchanged or extrapolated based on current practices in analyses of biomass resource supply, large changes are possible. Motivation and opportunity to undertake changes that allow biofuel feedstocks to be produced in large amounts without compromising food production have been quite limited to date. Rather than undersupply, the world's functional breadbaskets have been challenged by productive capacity exceeding demand over the last century, and in response to this situation the primary focus of agricultural policy has been to keep farmers in business and land in production. Furthermore, feedstock demand for biofuel production from row crops has been small relative to food production, accounting for about 4% of world grain production currently, and demand for biofuel production from inedible cellulosic feedstocks has yet to emerge. Looking forward to the possibility of biofuel production on a scale large enough to meaningfully impact sustainability and security challenges gives rise to legitimate questions regarding indirect land use change, with its potential for associated carbon emissions and habitat loss.

This paper addresses reconfiguring agricultural land-use to accommodate large-scale biofuel production. Forested land is a potentially substantial additional source of biomass for fuel production, but is not analyzed herein. To the extent possible based on available information, we seek to test the hypothesis that a substantial fraction of mobility could be powered by biofuels produced from currently managed agricultural lands without decreasing food production. Because complete development and evaluation of the multiple options by which this might be achieved represents an undertaking far beyond the scope of a single presentation, our analysis is necessarily exploratory. We focus primarily on cellulosic biomass, as this class of biofuel feedstocks is widely seen as having the greatest potential for large-scale energy production, and also offers the most extensive range of possibilities for integration into agricultural landscapes without displacing food production. Our scope here is limited to the United States in order to keep the analysis tractable, although we whole-heartedly acknowledge the importance of considering the biomass supply issue at a global scale.

Two categories of land-use changes are considered here: integrating biofuel production into agricultural land, and increasing the land efficiency of food production. Reducing fuel demand and dietary change are also addressed, based on analyses in the literature, in order to illustrate the potential complementarity between multiple changes.