Assessing operational benefits of large-scale energy storage in power system: Comprehensive framework, quantitative analysis, and decoupling method

With the large-scale integration of centralized renewable energy (RE), the problem of RE curtailment and system operation security is becoming increasingly prominent. As a promising solution technology, energy storage system (ESS) has gradually gained attention in many fields. However, without meticulous planning and benefit assessment, installing ESSs may lead to a relatively long payback period, and it could be a barrier to properly guiding industry planning and development. In this article, we present a comprehensive framework to incorporate both the investment and operational benefits of ESS, and quantitatively assess operational benefits (ie, energy transfer and ancillary services benefits). The time-sequential operation simulation method is introduced to quantify the different operational benefits more accurately. Finally, we analyze the coupling relationships among these benefits and design a decoupling method to separate them. A case study on a modified practical power system is investigated. Numerical results show that the operational benefits of ESS are fully investigated and properly measured. In addition, ESSs' operational benefits will increase with the RE penetration and proper selection of the installed capacity of ESSs.