Implications of Trends in Energy Return on Energy Invested (EROI) for Transitioning to Renewable Electricity

Abstract

Recent papers argue that the energy return on energy invested (EROI) for renewable electricity technologies and systems may be so low that the transition from fossil fuelled to renewable electricity may displace investment in other important economic sectors. For the case of large-scale electricity supply, we draw upon insights from Net Energy Analysis and renewable energy engineering to examine critically some assumptions, data and arguments in these papers, focussing on regions in which wind and solar can provide the majority of electricity. We show that the above claim is based on outdated data on EROIs, on failing to consider the energy efficiency advantages of transitioning away from fuel combustion and on overestimates of storage requirements. EROIs of wind and solar photovoltaics, which can provide the vast majority of electricity and indeed of all energy in the future, are generally high (≥ 10) and increasing. The impact of storage on EROI depends on the quantities and types of storage adopted and their operational strategies. In the regions considered in this paper, the quantity of storage required to maintain generation reliability is relatively small.