Multi-objective optimization and operation comparison of integrated energy system considering park-level energy load under different carbon emission reduction scenarios

To address different stages of energy transformation in the future, the integrated energy system (IES) is optimized and analyzed for best operation under different target weights and energy demands. Taking the investment cost, CO₂ emissions, and percentage of renewable energy as optimization objectives, the NSGA-III and TOPSIS algorithms are used to obtain the optimal solutions. The results show that ES-balancing CO₂ emission and economics (C-E-IES) can achieve an increase in the share of renewable energy and a significant reduction in CO₂ emission in a period when CO₂ emission reduction is not very urgent. Compared with the IES considering CO₂ emission reduction (C-IES), which mainly considers CO₂ emission reduction, the C-E-IES investment cost is significantly reduced. The investment costs of C-E-IES on a typical cooling day and a typical heating day are 46.91% and 66.89% lower than those of the C-IES, while the CO₂ emissions are 71.75% and 73.66% lower than those of the traditional IES (T-IES). The proportion of renewable energy in C-E-IES is still high, reaching more than 60%. An increase in renewable energy leads to a decrease in system energy efficiency, but C-E-IES can still reach 0.72 and 0.61. A sensitivity analysis of the main renewable energy equipment cost changes showed that a change in the wind turbine price has the most significant impact on the IES.