Algorithm for optimal sizing of energy storage system paired with photovoltaic generation considering lithium-ion battery degradation

There is growing interest in utilizing energy storage systems (ESS) to create combined “renewable energy plus storage” power plant. Lithium-ion battery based ESS draws much attention due to its high energy density and low self-discharge. Since Lithium-ion batteries are still costly, a power provider should determine ESS capacity in a sophisticate manner to secure profitability. Moreover, as Lithium-ion batteries are subject to degradation, this also needs to be considered in ESS capacity calculation. However, the degradation varies depending on the battery usage patterns and time and thus results in non-convexity in ESS capacity calculation. In this paper, we propose an iterative method to calculate the proper capacity of ESS paired with a PV system by considering battery degradation and profit maximization. ESS capacity calculation according to PV system size and economic evaluation according to REC weight change are conducted based on the case study of South Korea power market. Copyright The Korean Institute of Electrical Engineers