Towards Developing a Large Distributed Energy Storage Using a Weighted Batteries Scheduling Scheme

The energy storage system (ESS) is the next major disruption to the current architecture of the electricity grid. Energy storage offers several benefits to the electricity grid, which include frequency regulation, energy arbitrage, peak shaving, reducing intermittency of renewable energy sources (RESs), and many other benefits that are not possible without large energy storage. Large-scale batteries are still expensive and cannot be readily used with a reasonable return on investment. Aggregating a large number of consumers' small scale batteries may provide us with the benefits of large central storage. However, aggregated small-scale batteries have several advantages over large central storage. Small-scale batteries provide better scalability and open up many new investment opportunities for the grid as well as for the consumers. In this article, we present a control scheme for small-scale distributed batteries, namely, Weighted Batteries Scheduling (WBS) scheme to make a large distributed energy storage. We also present a method to calculate weights, that are required for the WBS scheme, by prioritizing the batteries with respect to the state-of-charge (SOC). We evaluate the fairness of the proposed scheme using Jain's fairness index and entropy-based fairness index. The proposed storage model can be used for any necessary support for the electricity grid. We study financial benefits obtained by the large distributed energy storage for frequency regulation, energy arbitrage and peak shaving. Frequency regulation appears to be of the highest value for energy storage. Our results show that a distributed storage consisting of 1000 small batteries each of 1 kW power achieves average daily revenue of $606.61.