My PhD research attempts to understand the uncertainties inherent in the life cycle assessment (LCA) of transportation fuels, and to explore the implications of these uncertainties on policy design.

The LCA of biofuels in particular faces a number interesting analytical challenges due to uncertainties in both data and model structure. On the data side, a key factor is the high temporal and spatial variability of emissions of nitrous oxide from soils--the single greatest contributor to greenhouse gas emissions from bioenergy crops. The aggregation and averaging of widely used agriculural data also masks variability and uncertainty. In terms of model structure, the greatest challenge is quantifying, or at least bounding, the climate effects of land-use conversion due to the expanded production of energy crops.

New fuel regulations are sprouting up world wide that plan to measure and regulate the climate effects of transportation fuels using a life cycle approach. A better understanding of the uncertainties--and therefore the limits in our abilities to distinguish meaningfully between alternatives--will provide a basis for improved policy design.

My master's research involved the environmental consequences (both positive and negative) of biofuels production and utilization. I'm interested in improved biofuel production pathways, including the use of wastes and residues as feedstocks and primary energy sources, and in the social and environmental affects of land use conversion from expanded biofuel production.

Other interests include climate change mitigation and energy systems modeling.

My dissertation research includes:

• A reduced-form model of biofuels-induced ("indirect") land use change, which I'm using to explore plausible boundaries on the resulting CO₂ emissions.


• Comparative uncertainty analysis of the life cycle GHG emissions for gasoline, diesel, electricity, and various biofuel pathways, including parameter uncertainty as well as several important model uncertainties. This work uses the GREET model and some custom software to convert GREET's probability distributions for use in Crystal Ball®.


• Analysis of USDA agricultural survey data to compute the life cycle greenhouse gas emissions of corn production using a "bottom-up" approach that treats each farm as a coherent system. I will also examine the differential effects on GHG emissions of different cropping and irrigation practices.


• Analysis of the robustness of Low Carbon Fuel Standards (such as California's) given the uncertainties examined above.

MS (2006), Energy and Resources Group, UC Berkeley
MS (1982), Computer Science, Yale University
BS (1981), Computer Science and Applied Mathematics, SUNY Albany

National Science Foundation Graduate Research Fellow (2006-2009)

I was a software engineer in my first career, working on Wall Street in the eighties, in Silicon Valley in the early nineties, and in the non-profit sector in the late nineties through about 2003. I spent 8 months in Thailand in 2003-2004 working with Palang Thai to promote the use of renewable energy in Thailand, with a focus on biogas production from manure and food processing waste. I started at ERG in 2004, focusing on sustainable uses of bioenergy.