Life cycle environmental and economic impacts of various energy storage systems: eco-efficiency analysis and potential for sustainable deployments.

The deployment of energy storage systems (ESS) plays a pivotal role in accelerating the global transition to renewable energy sources. Comprehending the life cycle environmental and economic impacts, as well as the necessary conditions and scenarios required for ESS deployment, is critical in guiding decision-making and supporting sustainable operations. In this study, we first analyzed the life cycle environmental impacts of pumped hydro energy storage (PHES), lithium-ion batteries (LIB), and compressed air energy storage (CAES). We then focused on elucidating the potential for carbon neutrality in existing PHES systems compared to LIBs in China by integrating various reduction measures to achieve net-zero emissions scenarios. Ultimately, we combined environmental and economic impacts to demonstrate the eco-efficiency of both ESS, supporting their sustainable deployment. Regarding environmental impacts, LIB is currently the most environmentally favorable ESS, followed by PHES. Various decarbonization measures revealed that transitioning to renewable energy sources is the most effective strategy for carbon reduction, with projected reductions ranging between 75 and 112% in both PHES and LIB systems. When implementing all carbon reduction strategies simultaneously, LIB is expected to achieve carbon neutrality by 2030, whereas PHES is projected to reach this milestone by 2040. With anticipated energy mix optimizations, carbon emissions are expected to further decrease to 22.2 kg CO2/MWh for PHES and 48.7 kg CO2/MWh for LIB by 2050. Economic analysis indicates that the life cycle cost per MWh for PHES is $66.5, approximately half that of LIB. Meanwhile, the payback period of PHES is 21 years, while that of LIB is 28 years to reach the break-even point. This disparity clearly underscores the superior economic benefits of PHES. The eco-efficiency of PHES is anticipated to surpass that of LIBs by 2028, rendering PHES a more favorable option in appropriate regions.