Alex Farrell
University of California at Berkeley
Abstract:
Resource depletion, energy security and climate change imperatives will require a large-scale substitution away from conventional petroleum over the next several decades, as well as improved vehicle efficiency. Recently, the ethanol has been suggested as possible alternative. However, the energy and environmental implications of ethanol are hotly debated and the literature contains studies with conflicting results. Comparing across published studies to evaluate how these assumptions affect outcomes is difficult owing to the use of different units and different system boundaries across studies. Finding intuitive and meaningful replacements for net energy as a performance metric would advance our ability to evaluate how to meet these pressing imperatives. To better understand the energy and environmental implications of ethanol and to investigate better performance metrics, we surveyed the published and gray literature and compared six studies illustrating the range of assumptions and data found for the case of corn-based ethanol. To permit a direct and meaningful comparison of the data and assumptions across the studies, we developed the Energy and Resources Group (ERG) Biofuel Analysis Meta-Model (EBAMM). This talk will discuss the analysis we performed with EBAMM to resolve the confusion about the issue, the uncertainties we have uncovered in doing so, and the implications of the results for both future research and public policy. A paper reporting some of these results, as well as the EBAMM model with all of the data are available online at http://rael.berkeley.edu/ebamm