Sizing Energy Storage to Accommodate High Penetration of Variable Energy Resources

The variability and nondispatchable nature of wind and solar energy production presents substantial challenges for maintaining system balance. Depending on the economic considerations, energy storage can be a viable solution to balance energy production with consumption. This paper proposes to use discrete Fourier transform to decompose the required balancing power into different time-varying periodic components, i.e., intraweek, intraday, intrahour, and real-time. Each component can be used to quantify the maximum energy storage requirement for different types of energy storage. This requirement is the physical limit that could be theoretically accommodated by a power system. The actual energy storage capacity can be further quantified within this limit by the cost-benefit analysis (future work). The proposed approach has been successfully used in a study conducted for the 2030 Western Electricity Coordinating Council system model. Some results of this study are provided in this paper.