Techno-Economic Dispatch Optimization of Integrated Energy Systems with Electric Vehicle Participation Considering Incentive Saturation Effects

Large-scale electric vehicle (EV) integration provides considerable flexibility for integrated energy systems (IESs), but stronger incentives do not always yield proportional demand response benefits under physical operating limits. This paper proposes a techno-economic dispatch optimization framework for an IES incorporating a Kalina Cycle (KC), power-to-gas (P2G) technology, and hydrogen storage. A 24 h mixed-integer linear programming (MILP) model is developed to evaluate the interaction among the incentive intensity, multi-energy load response, and operating cost under different integrated demand response (IDR) scenarios. The results show a saturation-like response pattern: as the incentive intensity increases, the total operating cost rises monotonically, while the total demand response does not increase proportionally. In the studied case, the low-incentive strategy achieves the best economic performance because the additional compensation paid under high-incentive scenarios outweighs the marginal operating-cost savings. Load response analysis further indicates that EV-dominated electrical loads provide the main flexibility, whereas thermal and gas loads are strongly constrained by physical balance and equipment limits. The ablation results show that the saturation trajectory is affected by physical flexibility resources, especially the hydrogen subsystem. These findings suggest that incentive design should be coordinated with system physical constraints to avoid over-incentivization.