Maximizing social benefit from finite energy resource allocation

Abstract

Background: Since the industrial revolution, human population and fossil energy consumption have steadily increased. With concerns over fossil energy impact on air quality and global climate, there is increasing interest in collection and conversion of non-fossil energy feedstocks. These finite renewable feedstocks (biomass, solar, wind) provide a challenge based on their land-limited supply and temporal availability. Consequently, society needs methodologies to increase end-user efficiency to maximize the energetic utility and sociological benefit from the finite land base. Methods: This paper presents a methodology for evaluating whole system effectiveness from a finite unit of biomass feedstock. By analyzing conversion of raw energy inputs into final energy services (FES) delivered in the form of transport or heat to society, we assess the FES returned on energy investment (ERoEIfes). Comparison of ERoEIfes across 11 different conversion pathways illustrates the relative delivered social benefit of each pathway derived from the same finite feedstock. Results: We found previously that New York (NY) could sustainably produce 14.2 Tg/y of biomass feedstocks from agriculture and forestry (equivalent to 7% of NY's primary energy consumption of 3.9 EJ). We found that high value FES as a percentage of energy in the biomass feedstock ranged from 5 to 15% for transport and 12 to 71% for heat (residential or commercial). However, the FES provided for six pathways was more than 2-fold higher if co-products were used. This method (1) internalizes energetic processing and use losses (2) to compare pathways and systems (3) that maximize services and value derived from land-limited sustainably harvested resources (4) thus providing a holistic approach increasing the value of a unit of land to generate primary energy resources, sustainably. Conclusion: This case study provides a framework to assess a range of conversion pathways for any finite energy feedstock for society. Across all biomass types and conversion processes, the replicable ERoEIfes methodology provides a foundation for decision-makers to compare FES delivered and then develop policies that reap the most benefit per unit of finite feedstock, thus assisting in more effective transition away from fossil-based feedstocks.