Assessing Multimetric aspects of sustainability: Application to a bioenergy crop production system in East Tennessee
This paper connects the science of sustainability theory with applied aspects of sustainability deployment. A suite of 35 sustainability indicators spanning six environmental, three economic, and three social categories has been proposed for comparing the sustainability of bioenergy production systems across different feedstock types and locations. A recent demonstration-scale switchgrass-to-ethanol production system located in East Tennessee is used to assess the availability of sustainability indicator data and associated measurements for the feedstock production and logistics portions of the biofuel supply chain. Knowledge pertaining to the available indicators is distributed within a hierarchical decision tree framework to generate an assessment of the overall sustainability of this no-till switchgrass production system relative to two alternative business-as-usual scenarios of unmanaged pasture and tilled corn production. The relative contributions of the social, economic and environmental information are determined for the overall trajectory of this bioenergy system’s sustainability under each scenario. Within this East Tennessee context, switchgrass production shows potential for improving environmental and social sustainability trajectories without adverse economic impacts, thereby leading to potential for overall enhancement in sustainability within this local agricultural system. Given the early stages of cellulosic ethanol production, it is currently difficult to determine quantitative values for all 35 sustainability indicators across the entire biofuel supply chain. This case study demonstrates that integration of qualitative sustainability indicator ratings may increase holistic understanding of a bioenergy system in the absence of complete information.