Life cycle assessment of a novel bipolar electrodialysis-based flow battery concept and its potential use to mitigate the intermittency of renewable energy generation

Abstract

The novel bipolar electrodialysis flow battery (BEDFB) concept is an acid-base type of energy storage solution that uses safe and abundant electrolytes and that has the potential of providing long-duration storage at low cost. To date, the potential environmental impacts of the BEDFB have not been investigated. Here, we report the results of a life cycle assessment (LCA) and an integrated sustainability analysis for a 1 MW/ 6 MWh BEDFB system having a 20-year lifetime. The manufacturing phase (cradle-to-gate) and the full life cycle (cradle-to-grave) were analyzed per 1 MWh (functional unit) of installed storage capacity using five LCA categories. For the use phase part of the LCA, the BEDFB was assumed to provide energy storage to support wind and PV generation within the national Mexican electricity grid. In addition, the cumulative energy demand (CED), the energy returned on investment (EROI) and three sustainability dimensions (feasibility, viability, desirability) were evaluated. Finally, we calculated the losses posed by the renewables that are currently (2019) deployed in the Mexican grid to assess the potential of energy storage deployment within the Mexican context. For the manufacturing phase, the BEDFB technology exhibited a terrestrial ecotoxicity value of 16.3 kg1.4DCB/MWh and a global warming impact of 9.1 kgCO2e/MWh, which are significantly lower values than reported for the state-of-the-art all-vanadium flow battery technology. PV generation in combination with the BEDFB demonstrated the best environmental profile, followed by generation through wind and the average Mexican grid conditions. We found that 304 BEDFB's would suffice to mitigate the energy losses represented by renewable deployments in Mexico today. The main result from the sustainability analysis is that, on the supply side, the BEDFB technology requires minimal fossil energy and chemicals during the upstream processes of the manufacturing phase.