Uncertainty of LCA for Algal Biofuel Production Seminar

Abstract

As a result of algae’s promise as a renewable energy feedstock, numerous studies have used Life Cycle Assessment (LCA) to quantify the energetic viability and environmental performance of algal biofuels, yet there is no consensus of results among them. Our work, motivated by the lack of comprehensive uncertainty analysis in previous studies, uses a Monte Carlo approach to estimate ranges of expected values of LCA metrics by incorporating parameter variability with empirically specified distribution functions. Results show that large uncertainties exist at virtually all steps of the biofuel production process. Although our findings agree with a number of earlier studies on matters such as the need for nutrients recovered from waste streams, wet lipid extraction, and high-energy co-products, the ranges of reported LCA metrics show that uncertainty analysis is crucial for developing technologies, such as algal biofuels. In addition, the ranges of energy return on (energy) invested (EROI) values resulting from our analysis help explain the high variability in EROI values from earlier studies. Reporting results from LCA models as ranges, and not single values, will more reliably inform industry and policy makers on expected energetic and environmental performance of biofuels produced from microalgae.

Dr. Deborah Sills

Dr. Sills is a researcher at the Cornell Energy Institute and her work focuses on applying quantitative uncertainty analysis to Life Cycle Assessment. In addition, she is working with two PhD students on a laboratory project that involves hydrothermal liquefaction of high lipid algal feedstocks. Finally, she teaches undergraduate courses at Cornell on sustainability and environmental engineering technologies.