A comparative sustainability assessment of several grid energy storage technologies

The global energy transition toward a low-carbon economy is driving increasing penetration of variable energy sources into electricity markets. This unprecedented deployment of intermittent renewables confronts decision-makers in the electricity sector with the challenge of selecting among different energy storage technologies, a choice that must be made on the basis of sustainability criteria. Existing studies present shortcomings, including the absence of the social dimension, the use of weights against sustainable development, or the application of methodologies affected by the rank reversal issue, among others. To address gaps in current knowledge, this study presents a novel probabilistic model for assessing the global sustainability of grid energy storage technologies. The model is based on the MIVES (Modelo Integrado de Valor para una Evaluación Sostenible)–Monte Carlo method, which combines requirement trees, value functions, the analytic hierarchy process, and probabilistic simulations. It consists of 19 indicators and makes it possible to obtain a sustainability index (SI), as well as partial economic, social, environmental, and technical indices for each technology. Data from an extensive literature review were integrated with expert input and estimations based on linear correlations to address challenges in assessing social and environmental indicators. The model was applied to six technologies: pumped hydroelectric energy storage (PHES), compressed air energy storage (CAES), liquid air energy storage (LAES), vanadium redox flow batteries (VRFB), sodium-sulfur batteries (NaSB), and hydrogen energy storage (HES). A comprehensive sensitivity analysis is also included. To the best of the authors’ knowledge, no existing study has utilized the innovative methodology presented in this paper, nor has any related research achieved the scope and depth proposed here. The top-performing technologies identified for the economic, social, environmental, and technical dimensions of sustainability are CAES, VRFB, LAES, and PHES, respectively. In terms of global sustainability, VRFB, LAES and PHES are the best options, while HES consistently ranks last. NaSB and CAES occupy intermediate positions.