In 2050, over 80% of the worldwide electricity demand is expected to be supplied by renewables. The mismatch between supply and demand resulting from these intermittent energy sources and the physical limits of existing electrical grids are challenges in this transition, for which batteries are part of the solution. Therefore, there is a renewed interest to develop advanced and environmentally sound batteries, which requires assessing their environmental impacts by means of life cycle assessment (LCA). However, in current LCA studies the use phase is insufficiently addressed and even oftentimes excluded due to complexity. The aim of this research was to gain insight into current approaches of modelling the use phase in existing LCA and footprinting studies to provide LCA practitioners with recommendations and improved approaches. A literature review was performed which included 26 papers, Annex II of Regulation (EU) No 2019/1020 and the PEFCRs for High Specific Rechargeable Batteries for Mobile Applications. Next to storing renewable energy, batteries can serve different services, also called applications. The implications of incorporating the utilisation of a battery for multiple applications simultaneously, i.e., value stacking, in modelling the use phase are discussed in a qualitative way, since this is emerging as a practical and economically beneficial operational strategy. Finally, the relative effect on a battery’s life cycle impact assessment (LCIA) scores of four issues identified in the literature review is analysed in an illustrative case study about an organic redox flow battery (ORFB).

It appears that many studies do not provide clear information on how the functional unit (FU) is specified, which application(s) the battery is utilised for, application characteristics, modelling assumptions including the electricity and battery inputs or complete LCI data. Overall, the degree of transparency of many battery LCA studies is mediocre which complicates judging the usefulness of results and should be improved to improve comparability and reproducibility for which recommendations are provided. Moreover, the interaction of battery parameters and application characteristics is captured in proposed modelling guidelines for the electricity and battery system input flows. Value stacking results in environmental benefits, particularly when a battery is used to store renewable electricity which is used to serve another application simultaneously. It seems only interesting for battery technologies with high cycle lives such as RFBs and some lithium-ion batteries because these offer the ability to increase battery utilisation without considerably decreasing the battery’s lifetime.

To reach sustainability ambitions, battery applications leading to a reduction in environmental impacts should be promoted for which a general incentive policy is not appropriate. Such policy stimulates all battery applications, which could lead to small or even negative contributions to environmental impact reduction compared to the current situation. Even though this is a temporary transition problem, it could lead to an undesirable interim increase of environmental impacts during the transition. To this end, performing comparative assessments of applications that are expected to be served by batteries in the future, requiring the involvement of transmission network operators, and how these are served in the current situation are useful.