Optimal BESS Sizing for PV Interconnection & Energy Arbitrage with Industrial Customers

Increasing commercial and industrial (C&I) customers are on board with a clean-energy future by installing photovoltaic (PV) systems at their facilities to compensate for the electricity supplied by the utilities. On the other hand, utilities may require no reverse power flow back to the bulk power system unless the customer is willing to pay potential network upgrading costs and follow ISO/RTO’s interconnection process. In the meantime, most equipment and devices of C&I customers are sensitive to voltage fluctuations caused by fault or switching events in the utility’s system. Voltage quality is a challenge to both the customer and the supplying utility. Therefore, a battery energy storage system (BESS), which can control power flow and is able to provide a fast response to voltage fluctuations during system events, is one of the best solutions. In addition to maximizing the PV penetrations, the BESS can be further utilized to track the locational marginal prices (LMPs) for energy arbitrage. As a result, a multi-objective optimization problem is needed to size the BESS to maximize the “bang for the buck”. This paper presents a real-world case study for a manufacturing customer to achieve decarbonization, arbitrage, and voltage quality improvement using a BESS optimal sizing algorithm and practical considerations. We believe the proposed approach can be adopted by other utilities or renewable developers for similar C&I customers.