Hybrid Approaches to Quantify the Environmental Impacts of Renewable Energy Technologies: A Comparison and Methodological Proposal

Abstract

The transition towards a more sustainable and decarbonised energy system is mandatory for achieving global climate objectives, and renewable energies are essential to this purpose. There are different methodologies to assess the sustainability, each with its strengths and limitations. Thus, hybrid approaches integrating Input-Output analysis and Life Cycle Assessment (LCA) are often proposed to overcome limitations and take advantage of strengths of renewable technologies. Through a case study of Concentrated Solar Power (CSP) technology, a potentially significant technology in the European context, this study provides an environmental assessment of seven environmental indicators by applying and comparing methodological approaches: Environmental Extended Multiregional Input-Output (EMRIO), Life Cycle Assessment and two hybrid approaches used in literature. Among those, we propose a new hybrid tieredapproach, named Identification and Subtraction Method (ISM), that expands the boundaries of the LCA method, identifying in MRIO results the impacts from sectors not included in the LCA. The results indicated that the LCA and EMRIO approaches provide impact values in the lower and upper ranges, respectively, although there are some exceptions. The proposed ISM method achieves to expand the LCA boundaries by including indirect impacts, avoiding any double-counting and retaining the technological detail and representativeness of the process-based LCA.The highest differences between methods are found in the assessment of local impacts and the depletion of the resources for either fuels or minerals and metals, while the methods tend to agree more on the quantification of global and regional impacts. However, there are limitations to the implementation of the impact characterization methods and the quantification of the potential impacts that should be borne in mind when comparing the results of the different methods.