Grid-Connected Battery Energy Storage Systems for Power Modulation: A Holistic Assessment Framework

The United States currently relies on fossil fuels for energy production, as large-scale renewable energy use is not conducive to the current power grid infrastructure. The most prominent renewable sources—solar and wind—stochastically produce power and challenge the maintenance of constant frequency, and the matching of supply and demand on the electricity grid. As a result, more than 2,000 GWh of energy was curtailed by independent system operators (ISOs) in 2022 [1]. Therefore, energy must be stored during times of overproduction and sold back to the grid during times of underproduction and high demand to eliminate the need for fossil fuels. Battery Energy Storage Systems (BESSs) arise as an attractive grid supplement that may manage this stochastic power because of their storage performance, ability to modulate power, and ease of development compared to other Energy Storage Systems (ESSs). While different types of BESSs are currently being developed, estimating the economic and environmental impacts of their integration into the electricity grid becomes a challenge [2]. This work aims to address and balance the profitability and environmental impact of integrating different types of BESSs—such as Sodium-ion batteries (SIB) [3] and lithium-ion batteries (LIB) [4]—into the grid. To assess economic performance of BESSs in power markets, optimal bid-in strategies for the day-ahead market, real-time market, and frequency regulation market were found for all ISOs in the US. To assess environmental performance for the same BESSs, a lifetime cycle assessment (LCA) cradle-to-grave framework for power-modulating systems was created to quantify the environmental impact that the integration of batteries into the grid with the optimal bid-in strategies may have. Initial economic feasibility results highlight that participation in day-ahead markets can generate $100,000-$400,000/year/MWh capacity depending on the given ISO. The LCA framework will be applied to example SIB and LIB systems, and results will show a holistic analysis of the implementation of BESSs as power-grid supplements for sustainable energy retention.