## 2 Related Work
### Carbon Emission Reduction in a Regional Integrated Energy System
#### 2.2.2 Market Mechanism Level  
To address the imperative for carbon emission reduction, various policies and measures utilizing market operation mechanisms have been proposed, leading to the rapid development of carbon-trading and green-certificate-trading mechanisms. The fundamental principle of carbon trading involves buyers, unable to meet carbon emission allowances independently, purchasing carbon emission rights from sellers to offset their shortfall, or else facing penalties. Green certificate trading entails the government issuing green-trading certificates for renewable energy generation by enterprises, which can be bought and sold among energy companies. There have been numerous studies focusing on carbon reduction within the context of regional integrated energy systems under carbon-trading and green-certificate-trading mechanisms. [PERSON] et al. [34] conducted a feasibility study on park-level integrated energy systems, incorporating distributed wind power, rooftop photovoltaics, and high-capacity wind power technologies. The analysis considered the carbon-trading mechanism, revealing that high-capacity wind systems have significant emission reduction effects. All the regional integrated energy systems achieved higher profits compared to those not participating in the carbon-trading mechanism. [PERSON] et al. [35] proposed a low-carbon multi-energy virtual power plant model that took the impact of the carbon-trading mechanism into account. Simulation results demonstrated that carbon-trading revenue could notably reduce daily dispatching costs by 20.00% and decrease carbon emissions by 19.21% compared to traditional economic dispatch models. [PERSON] et al. [36] introduced a dispatch optimization method for regional integrated energy systems, aiming to ensure a balanced and stable energy supply while considering the impact of carbon trading.  
The method established a daily optimization dispatch model for a regional electrical and gas integrated energy network, incorporating a priority model for multi-energy devices. The objective function included the sum of energy output costs, energy conversion costs, and carbon-trading costs resulting from net carbon emissions. The optimization aims to achieve the optimal output of different forms of energy, thereby reducing energy costs and carbon emissions under the carbon-trading mechanism. [PERSON] et al. [37] developed a two-stage fuzzy-logic-based stochastic programming method for energy system planning in Shanghai, introducing the carbon-emission-trading mechanism and green-certificate-trading mechanism. The experimental results demonstrated that the synergistic effect of the carbon-trading and green-certificate-trading mechanisms could transform Shanghai's energy structure to a clean production mode and effectively reduce carbon emissions. [PERSON] et al. [38] combined the carbon-trading and green-certificate-trading mechanisms, incorporating the carbon-trading costs and green-certificate-trading costs of the park's electric-thermal coupling system into the objective function. They proposed a planning model for the park's integrated energy systems with distributed photovoltaic access. The results showed that the carbon-trading mechanism and green-certificate-trading mechanism could effectively promote the low-carbon transformation of the park. [PERSON] et al. [39] took into account the challenges of wind power integration and established a \"source-load\" bilateral complementary coordinated optimization dispatch model based on green certificates and in combination with the carbon-trading mechanism. Using an adaptive immune vaccine algorithm to solve the model, the results showed that the combination of carbon trading and green-certificate-trading mechanisms facilitates wind power consumption and reduces the carbon intensity.