Cooperative operation optimization of natural gas pipeline network and underground gas storage: economic scheduling and low-carbon control

With the growth in natural gas consumption and the implementation of the “Dual Carbon” policy, supply-demand balance and low-carbon management of natural gas pipeline network (NGPN) system are facing important challenges. This paper established a comprehensive economic and environmental optimization model of NGPN system integrating the structural and hydraulic characteristics of underground gas storage (UGS) to respond the multi-period changes of user demand by deciding the NGPN scheduling and UGS injection-withdrawal schemes. To promote low-carbon management, the model considers the carbon emission targets of the NGPN compressor stations and the UGS compressor groups, and innovatively couples the differential pressure power generation (DPPG) optimization of the UGS expander groups. A high-dimensional linearized relaxation method combining piecewise linear approximation and spatial grid approximation is designed to overcome the complex nonlinear properties of the model. The results show that the optimized NGPN scheduling scheme reduces the carbon emissions of compressor stations by 16.34 %. Through the rational decision of UGS injection-withdrawal scheme, the carbon emissions of compressor groups were reduced by 23.35 %, and the green electricity generated from the DPPG of expander groups further reduced the carbon emission of 6745.3 tons. Moreover, the influence of pipeline flow rate allocation and flow direction decision on system operation is analyzed, and the advantages of UGS in balancing supply and demand are verified. This study can provide decision support for low-carbon operation management of NGPN system with UGS.