This study proposes a novel output curtailment method of renewable energy sources (RESs) to mitigate grid congestion while balancing curtailment minimization and fairness among power producers, considering the operational efficiency of system operators. This method is based on creating zones using sensitivity analysis and clustering grid congestion conditions. Recently, the large introduction of RESs has raised concerns of grid congestion in power systems. To mitigate congestion, the system operator curtails the output of RESs; however, the curtailment should be minimized while ensuring equal generation opportunities among power producers. The proposed method divides RESs into multiple zones according to the congestion mitigation effect of their output curtailment and uniformly curtails them in each zone. Moreover, the method divides congestion conditions throughout the year by clustering and creates zones of RESs for each congestion pattern. This approach aims to apply the optimal zone division of RESs according to the congestion condition, while removing the burden on the operator to recreate the zone division for each time step. A simulation was conducted to evaluate the effectiveness of the proposed method using a bulk power system model in the northern area of Tohoku region of Japan. Based on the simulation results, our proposed method outperforms existing approaches in terms of minimizing RES curtailment and promoting fairness across power producers, while considering the frequency of zonal creation.

The large-scale integration of renewable energy sources (RESs) has raised concerns regarding grid congestion in Japan. Battery energy storage systems (BESSs) can mitigate congestion by adjusting charging schedules; however, BESS owners basically prioritize market arbitrage, which may not be aligned with congestion mitigation. This paper proposes a charging incentive design to guide arbitrage-oriented BESS charging toward time periods that are effective for grid congestion mitigation. The system operator predicts congested hours and ensures that BESS owners can purchase electricity at the lowest daily market price. This design intends to shift the BESS charging time towards congestion periods. Because market prices tend to decline during congestion periods, the proposed method reduces the operator’s financial burden while encouraging congestion-mitigating charging behavior. Numerical simulations using a simplified Japanese east-side power system model demonstrate that the proposed method reduced the congestion mitigation costs by 3.86% and curtailed the RES output by 3.89%, compared to using no incentive method (current operation in Japan). Furthermore, additional payments to BESS owners accounted for only around 7% of the resulting cost savings, indicating that the proposed method achieved lower overall system operating costs.