Cumulative Overall Resource Efficiency Assessment (COREA) for comparing bio-based products with their fossil-derived counterparts

Abstract

Bio-based products potentially decrease consumption of non-renewable fossil resources compared to their fossil-derived counterparts, but are more demanding for bio-productive land use. Although thermodynamics-based resource accounting methods are available for calculating overall resource efficiency from a life cycle perspective, their accounting for bio-productive land resources as an input during quantification of efficiencies is unclear. This paper aims to fill the gap in scientific literature about how to calculate a cumulative overall resource efficiency indicator by developing a framework, called Cumulative Overall Resource Efficiency Assessment (COREA). COREA (i) takes into account bio-productive land resources and (ii) addresses the non-renewable character of fossil resources. To account for bio-productive land resources, two methodological questions need to be addressed: (1) “how to define the system boundary of the solar energy input in the primary biomass production system?” and (2) “how to choose the temporal system boundary of this system?”. Resource efficiencies are calculated for three cases at crop level and two cases at bio-based product level. To account for the non-renewable character of fossil resources, we propose an accounting approach that includes the ancient solar energy consumption of fossil resources. This methodological choice is illustrated through comparing the resource efficiencies of the two bio-based products with their fossil-based counterparts. The results showed that the bio-based products only had a higher resource efficiency than their fossil-derived counterparts if fossil resources were considered as ancient consumers of solar energy.