A sustainability assessment framework for an algal-based biorefinery

Abstract

Algal-based biorefineries are proposed as a solution to current environmental and economic problems of algal-based biofuels. This multi-product perspective decreases the environmental impacts of the main product and increases the economic viability of the conversion facility. These statements are validated by different assessments from a technological, environmental and economic perspective. However, the analysis of environmental impacts of algal-based biorefineries is characterized by the lack of common system boundaries, discrepancies in assumptions, the lack of a common set of environmental indicators and the exclusion of scale effects. Moreover, the economic viability of the process is mostly ignored or assessed in a separate analysis, without considering technological and market risks. An upcoming trend in economic evaluations of algal-based biorefineries is the execution of a techno-economic assessment. However, not all techno-economic assessments fully integrate the technological process. A generic framework is missing and problems such as the lack of common system boundaries and exclusion of scale effects are encountered. Moreover, this techno-economic assessment does not include environmental aspects. This paper proposes a generic framework which integrates a full environmental impact assessment in a techno-economic assessment. The suggested methodology can be performed during each stage of technology development. It provides a harmonized set of process boundaries and assumptions, the inclusion of scale effects, the identification of relevant environmental, technical and economic indicators and a full-scale risk assessment. This integrated assessment, in comparison to separate assessments, saves much time and effort.