Microgrid energy optimal scheduling in ports incorporating the bidirectional event trigger mechanism

Coordinated scheduling of port logistics and energy systems is essential for improving the economic and environmental performance of electrified ports. However, existing studies often optimize logistics operations and energy management separately, without adequately accounting for their strong coupling or the mismatch in operating time scales between logistics activities and energy resources. To address this issue, this paper proposes a day-ahead and real-time multi-time-scale coordinated scheduling framework for port microgrids with a bidirectional event trigger mechanism (BETM). In the day-ahead stage, an hourly mixed-integer linear programming (MILP) model is developed to jointly optimize berth and quay crane assignments, renewable energy utilization, grid electricity procurement, and energy storage dispatch, thereby generating a feasible baseline schedule. In the real-time stage, system operation proceeds at 15-min intervals, with system states and short-term forecasts continuously updated to account for operational uncertainties. BETM simultaneously monitors logistics-side and energy-side deviations from the day-ahead baseline and activates re-optimization only when the triggering conditions are met. Once triggered, the real-time MILP is re-solved over a 1-h prediction horizon and implemented in a rolling-horizon manner, thereby enhancing disturbance adaptability while avoiding unnecessary schedule revisions. Adaptive time-varying thresholds are designed according to system operating conditions. Case studies based on Tianjin Dongjiang Port show that, compared with model predictive control (MPC) and a logistics event trigger mechanism (LETM), the proposed method reduces total operating cost by 18.64% and 22.44%, respectively, while decreasing total online solution time by 88.90% and 77.76%, respectively. Moreover, it achieves near-zero renewable energy curtailment and favorable environmental performance in terms of peak-load reduction, carbon intensity, and renewable energy utilization. These findings demonstrate the potential of the proposed framework to enhance the cleaner production performance of electrified ports through improved economic efficiency and low-carbon energy utilization.