Assessment of the Capacity Credit of Renewables and Storage in Multi-Area Power Systems

Capacity credit (CC) can be defined as the capacity of conventional generators that can be replaced by renewable energy sources (RES) and/or other resources such as energy storage without reducing system reliability. Conventional approaches for calculating CC typically treat the power system as a single area without considering transfer constraints and reliability of interconnectors. However, in multi-area power systems locational aspects are key to assess tradeoffs and synergies arising from transmission, storage and RES in providing adequacy of supply. In this work, we propose a new methodology to quantify the CC of RES and storage in a multi-area power system. Due to the large computational burden brought about by composite system adequacy evaluation, a new accelerated sequential Monte Carlo simulation strategy and a new adaptive sampling approach are specifically developed to achieve computation efficiency. The proposed methodology is tested by demonstrating the impact of interconnectors' transfer constraints and availability on RES-storage CC in the case of the Australian National Energy Market (NEM) multi-area power system, with applications to wind, solar, and pumped hydro storage plants. The results from several realistic NEM case studies highlight how the proposed model can inform strategic, reliability-aware integrated system planning of large-scale interconnected low-carbon power systems.