Carbon-aware optimal dispatch of park-level integrated energy systems considering renewable certificate and emission trading coupling

Integrated energy systems (IESs) provide an effective framework for coordinating electricity, heat, cooling, gas, renewable generation, and energy storage. However, existing low-carbon dispatch models often treat tradable green certificates (TGCs) and carbon emission trading (CET) as independent economic terms, which weakens their ability to reflect the operational link between renewable accommodation and carbon allowance constraints. This paper proposes a carbon-aware multi-objective optimal dispatch method for a park-level IES with TGC-CET coupling. To prevent transactional double use, certificate selling and retirement are modelled as mutually exclusive channels. Renewable consumption reduces physical emissions through dispatch, whereas retired quota-surplus certificates affect only a separately reported policy-credited carbon position. This counterfactual credit is not physical abatement and is not an offset instrument under the current Chinese national ETS. A mixed-integer linear programming model is formulated to minimize operating cost and credited carbon position while maximizing renewable energy consumption. The epsilon-constraint method generates the Pareto frontier, and TOPSIS selects the compromise dispatch strategy. Compared with independent CET and TGC operation, the proposed method reduces operating cost from 28,499 CNY to 28,205 CNY, decreases physical carbon emission from 21.70 tCO2 to 21.20 tCO2, reduces the credited carbon position to 14.20 tCO2 by retiring 12.05 MWh quota-surplus certificates, and increases renewable consumption from 92.1% to 96.6%. Relative to the independent-market case, the physical improvements are modest (1.03% lower cost and 2.30% lower physical emissions); the larger reduction in the credited position is an accounting effect rather than additional abatement.