Energy storage sizing for grid compatibility of intermittent renewable resources: A California case study

High levels of intermittent renewable sources will lead to large swings in demand for other generation resources, increasing the risk of overgeneration. Rooftop solar installations exacerbate the potential issues as well. Energy storage systems can mitigate these problems but need to be properly sized to reach network wide goals. This paper presents a method to estimate the necessary energy capacity and power for storage systems to align intermittent resources with network ramp-rate limitations. Case studies for the California Independent System Operator in 2017 and projecting to the renewable portfolio standard target of 60% in 2030 are presented. The effect of curtailment on storage requirements is also analyzed. Lastly, the impact of behind-the-meter solar installations in the Los Angeles area is estimated. These analyses show that significant amounts of storage and some curtailment will be necessary to reach the RPS targets given current network ramping limits unless other dispatchable renewable resources are deployed. This is the first step to develop grid-level planning tools by estimating storage needs with consideration of the demand, renewable generation characteristics, and curtailment levels. (C) 2020 Published by Elsevier Ltd.