Optimizing long-term park-level integrated energy system through multi-stage planning: A study incorporating the ladder-type carbon trading mechanism

The integrated energy system is widely acknowledged as an effective method for advancing the adoption of renewable energy sources and reducing carbon emissions. To address economic issues caused by the inconsistency between traditional single-stage planning capacities of the park-level integrated energy system (PIES), the long-term planning model is proposed, which consists of multi-stage divisions and incorporates the ladder-type carbon trading mechanism. The model utilizes the long-term, multi-stage planning approach to determine the optimal installed capacity of equipment. Meanwhile, the ladder-type carbon trading mechanism is conducted considering the relationship between actual carbon emissions, carbon emission quotas, and carbon trading cost. The study assesses the impact of carbon trading mechanisms and various planning stage divisions on the economic feasibility of the PIES and its ability to reduce carbon emissions. The results indicate that compared to fixed carbon price trading strategies, the implementation of ladder-type carbon trading increases costs by 0.15 %–0.18 %, but reduces carbon emissions by 0.36 %–0.6 %; as the number of planning stages increases, carbon emissions significantly decrease, and lifecycle costs also significantly decrease. Compared to traditional single-stage planning, carbon emissions decrease by 14.6 % and lifecycle costs decrease by 15.17 % at number of planning stage K = 15; when the baseline price is set at 0.5 yuan/kg and the price growth rate is 0.5, the optimal values of carbon emissions and carbon trading cost are achieved. In conclusion, this study serves as references for the strategic implementations of PIES, emphasizing the importance of economic efficiency and low-carbon practices in line with the system's long-term development and sustainability objectives.