(120c) Using System Dynamics to Support Consequential Life Cycle Analysis: The Forest Based “Drop-in” Biofuel Supply Chain Example

The biofuel research and production sector is enjoying an unprecedented amount of public and private effort in order to remove various financial and technical barriers. One of these very important barriers is the challenge of developing biofuels that are compatible with existing gasoline, jet fuel and diesel infrastructure. The United States Department of Energy has been championing efforts that ensure that the next generation of biofuels will be regarded as “drop-in” biofuels. According to the Former Undersecretary of the United States Department of Energy, Kristina Johnson,  “drop in” biofuels can be defined as fuels produced from various biomass which are compatible with the over $9 trillion energy refinery and gas station infrastructure currently available in the United States (Excerpts from the 4th Annual Cellulosic Biofuel Summit 2009 ).

Biofuel production involves the use of biomass raw materials extracted from the environment, which are transported to processing sites where the biomass is converted into biofuels. From these processing sites, the produced biofuel is then conveyed to end users through distribution points. It is therefore important to acknowledge the effects of activities and processes at each stage of the life cycle of biofuels on sustainable development – economic feasibility, environmental soundness and social acceptance. A Life Cycle Assessment (LCA) that looks at describing the environmental profile of the whole supply chain of drop-in biofuels is thus important.  There are two types of LCA methodologies - the attributional LCA which uses average data for each unit process and the consequential LCA which relies on marginal data for its analysis (Ekvall and Andrae, 2006). Additionally, attributional LCA analysis defines the status quo whilst the consequential LCA measures the impacts through changes in the physical flows.

System dynamics is a mathematical and methodological approach used in understanding complex systems over time. It helps us to better understand the interactions that will go into producing results when interactions between components of a system are simulated. The coupling of system dynamics with a consequential LCA conducted on forest based “drop-in” biofuels in the state of Maine can reveal many intriguing facts that might not be revealed in the forecasting associated with consequential LCA. System dynamics will help us gain qualitative insights into understanding the intricacies of economic, ecological and social issues when they interact with biofuel systems. The results of this study will be presented at the meeting.