Low-carbon optimal dispatch of an electricity–gas–heat–hydrogen integrated energy system considering carbon capture and stepped carbon trading under the new power system

The high penetration of renewable energy in new power systems increases supply variability and intensifies source–load fluctuations, creating challenges for coordinated energy management, reliable energy supply, renewable energy accommodation, and low-carbon operation. To address these challenges, this study proposes a low-carbon optimal dispatch method for an electricity–gas–heat–hydrogen integrated energy system that coordinates multiple energy carriers and exploits their complementary conversion, storage, and regulation capabilities to enhance system flexibility and alleviate mismatches between renewable energy output and multi-energy demand.

An electricity–gas–heat–hydrogen multi-energy integrated system is constructed using power-to-gas equipment, an adjustable combined heat and power unit, and a hydrogen fuel cell. Their coordinated operation strengthens the coupling among electricity, gas, heat, and hydrogen and provides additional capabilities for energy conversion and temporal shifting. In terms of the low-carbon mechanism, carbon capture and storage (CCS) and stepped carbon trading are introduced into the dispatch framework. CCS reduces the system’s actual net carbon emissions, whereas stepped carbon trading incorporates emission costs into the operating objective and encourages low-carbon operation. On the load side, a diversified demand response model is established according to the flexible characteristics of electric, heat, and gas loads and adjusts flexible demand within the permitted range, thereby enhancing load-side regulation and improving coordination between energy production and consumption. On this basis, a multi-objective optimal dispatch model is formulated to minimize the total operating cost and maximize the load satisfaction rate and renewable energy utilization rate. The model is solved using an improved particle swarm optimization algorithm combined with the entropy-weight method to achieve coordinated optimization of economic performance, energy supply, and renewable energy utilization.

The results show that the proposed dispatch strategy can effectively coordinate the operation of the electricity, gas, heat, and hydrogen subsystems. In particular, the time-shifting capability of hydrogen storage enables energy to be transferred across different operating periods, reducing the temporal mismatch between renewable energy generation and load demand and helping to mitigate fluctuations in renewable energy output while improving source–load balance. The diversified demand response model further releases the adjustment potential of electric, heat, and gas loads and supports the coordinated dispatch of multiple energy carriers. Through the combined effects of multi-energy coupling, demand response, stepped carbon trading, and CCS, the system maintains high load satisfaction and renewable energy utilization rates while substantially reducing actual net carbon emissions. The results also demonstrate that hydrogen energy plays an important role in smoothing source–load fluctuations and strengthening system flexibility.

The coordinated application of multi-energy coupling, diversified demand response, stepped carbon trading, and CCS provides an effective approach to the low-carbon dispatch of electricity-gas-heat-hydrogen integrated energy systems, balancing operating economy, load satisfaction, renewable energy utilization, and carbon-emission reduction while improving the system’s capability to accommodate high proportions of renewable energy. It therefore provides a useful reference for the flexible, coordinated, and low-carbon operation of multi-energy systems under source–load fluctuations.