Environmental Benefit-Detriment Thresholds for Flow Battery Energy Storage Systems

While energy storage systems (ESS) are required to integrate and manage renewable resources on the electric grid, ESS can result in life cycle environmental impacts associated with (1) the production of the system, (2) the use of the system, and (3) the end-of-life of the system. As more energy storage capacity is deployed, the grid benefits and associated life cycle environmental impacts may not scale the same. For example, thresholds of energy and power capacity may exist beyond which additional energy storage results in a negative environmental impact. To explore this question, this study addressed the use-phase environmental impacts of three flow-battery energy storage systems. Dynamic electric grid modeling tools were used to establish the use-phase environmental benefits and impacts on Global Warming Potential (GWP), Particulate Matter (PM) emissions, Acidification Potential (AP), and Fossil Fuel Cumulative Energy Demand (CED) as the aggregate ESS power and energy capacity installed on the electric grid is increased. For an electric grid with a high percentage of renewable resources, the results reveal that (1) the use-phase impact can be as, or more significant than, the production - phase depending on the grid composition, (2) the combined power and energy capacities for flow battery systems where the net environmental benefits are a maximum, and (3) that power and energy capacities must be limited to certain thresholds in order to ensure that flow-battery storage provides net environmental benefits