Environmental impact of energy storage technologies and future renewable grids

Energy storage technologies are essential for enabling high-renewable electricity systems, but their broader environmental effects are currently underexamined. This study conducts a harmonised Life Cycle Assessment (LCA) of two fossil-based peaking systems and nine storage technologies, covering pumped hydro, compressed/adiabatic air (CAES, ACAES), concentrated solar with thermal storage (CSP-TES), PV/Wind-Battery, and PV/Wind-ACAES, using the Environmental Footprint 3.1 method. The novelty of this work lies in the use of 16 distinct environmental impact indicators—extending analysis beyond climate change to include toxicity, eutrophication, land use, resource depletion etc. The impact of the study is through the quantification of environmental burdens across each indicator, enabling a full-spectrum evaluation of trade-offs. A core contribution is a direct cross-comparison of mechanical, thermal, and electrochemical technologies under standardised boundary conditions, supported by weighted endpoint scoring methods that facilitate consistent benchmarking. Results show that Wind-ACAES and -Battery, perform best in climate change assessment (0.028–0.064 kgCO₂eq/kWh), and best under holistic environmental evaluation (0.024–0.093 index score). These are followed by CSP-TES and PV-BESS (0.11–0.14 kgCO₂eq/kWh, 0.08–0.226 index score), where the former offers low eutrophication and particulate matter impacts, while the latter has high mineral resource depletion and land use impacts. Furthermore, the scenario modelling for the US, China and UK future renewable grid integration, illustrates how storage systems interact with decarbonisation pathways. The significance of these findings lies in demonstrating that energy storage, whilst central to displacing fossil fuel generation (8.4–11.5%/yr.) and integrating variable renewables, has a minimal impact. Considering a 100% storage adoption, the storage infrastructure emissions represented only 8–13% of the annual CO₂ impact, for the 2040 projected renewable grids, with wind and solar expansion. Hence, this study demonstrates how to critically evaluate the supporting cases with lifecycle-aware deployment strategies and advises on the required policies, as storage becomes an increasingly central component of global energy transitions.