Harnessing carbon regulation capacity in urban electricity-gas systems: A coordinated planning framework embedding aggregated feasible region

Urban electricity-gas systems (UEGSs) play a critical role in energy decarbonization. However, their carbon regulation capacity remains underexplored, as existing methods rarely aggregate flexible resources to reserve sufficient carbon-related operating margins to support regional systems under stricter emission quotas and carbon intensity fluctuations. Therefore, this paper proposes an aggregated carbon-feasible region (ACFR)-based coordinated planning framework to quantify and enhance the carbon regulation capacity of UEGSs. The ACFR aggregates the electricity-gas operational region into a low-dimensional carbon state space to simultaneously characterize local emissions and regional regulation margins. Based on this, a coordinated planning model is formulated to co-optimize storages and energy coupling components while considering investment cost, carbon emissions, and carbon regulation capacity. A synergistic solution method integrating region aggregation and parallel genetic algorithm is then developed to reduce computational burden. Medium-scale numerical experiments show that the proposed framework tolerates an additional 14% carbon quota tightening and a 4.89-fold increase in regional carbon intensity, demonstrating its effectiveness in significantly enhancing carbon regulation capacity with limited economic sacrifice. For large-scale experiments, the proposed algorithm reduces operation variables by up to 98.66% and total computation time by 32.3%, verifying its scalability in large-scale UEGSs.