4-Hour Rolling Dispatch Strategy for Wind-Deficient Evening Peak

During evening peak load periods with unexpectedly low wind power output, provincial dispatchers must rapidly adjust generation schedules to maintain grid reliability while minimizing operational costs. This scenario demands a 4-hour rolling dispatch strategy that dynamically coordinates thermal plants, energy storage systems, and available renewable resources. The key challenge lies in balancing the inertia and ramp capabilities of thermal units against the fast-response flexibility of storage, all while respecting economic dispatch principles.

First, establish a baseline forecast for the upcoming 4-hour period by updating wind predictions with the latest meteorological data and confirming actual load curves. For thermal units, prioritize units with lower marginal costs and faster ramp rates, such as combined-cycle gas turbines, and keep coal units at minimum stable loads to avoid costly shutdown-startup cycles. Energy storage systems should be scheduled to provide peak shaving during the highest net load hours. For example, discharge storage in the first two hours of the evening peak, then recharge during off-peak intervals if wind output recovers later. This thermal-storage coordination reduces reliance on expensive peaking gas turbines.

Next, implement a rolling optimization window: every hour, update the dispatch schedule for the next 4 hours using a security-constrained economic dispatch algorithm. Include constraints for minimum up/down times for thermal units, state-of-charge limits for storage, and wind curtailment thresholds. To balance stability, maintain sufficient spinning reserve from both fast-ramping storage and partially loaded thermal units. Cost optimization can be achieved by adjusting storage discharge rates to offset the most expensive thermal generation during peak hours, while keeping thermal units operating near their best efficiency points. Finally, continuously monitor frequency and voltage stability, and have a contingency plan for sudden wind drops or load spikes—such as activating demand response or emergency storage reserves. This integrated approach ensures the grid remains stable and cost-effective even under adverse wind conditions.