Objective In light of the “carbon peaking and carbon neutrality” goals, China’s natural gas demand is expected to grow rapidly until 2040, necessitating an expansion of the natural gas pipeline network. Traditionally, the layout of natural gas pipeline network has focused on point-to-point local matching between resources and markets, neglecting the distribution of national market demand and overall resource allocation optimization. This approach is inadequate for the planning, construction, and operation of “one pipeline network nationwide”. Therefore, a scientific and systematic methodology must be established to guide the planning and layout of the natural gas trunk pipeline network during the “15th Five-Year Plan” period and beyond.

Methods A simplified “zone + channel” model of the trunk pipeline network was developed based on the spatial distribution of national resource markets and the characteristics of the existing natural gas trunk pipeline network. A flow direction and volume analysis method was established, taking the minimum turnover as the optimization objective and the pipeline throughput as the constraint. The GNU Linear Programming Kit (GLPK) solver was employed to calculate the load rate of each channel. Utilizing the principle of N−1, the maximum load rate for each channel was established, enabling the identification of bottlenecks. Based on these bottlenecks, several feasible planning and layout schemes were proposed. A comprehensive evaluation index system, incorporating construction investment, operational energy consumption, and other factors, was developed to determine the optimal planning and layout scheme based on minimizing overall costs.

Results Based on the projected natural gas supply and demand data for 2040, the analysis of flow direction and volume identified four main bottlenecks in the existing natural gas trunk pipeline network, leading to the proposal of three feasible planning and layout schemes. The comprehensive comparison determined that China should plan for channels Ⅰ, Ⅲ, Ⅵ, and Ⅷ in the future.

Conclusion The simplified “zone + channel” model of the trunk pipeline network effectively highlights core issues in natural gas resource allocation and provides data support for optimizing pipeline network transmission schemes. The development of bottleneck identification criteria based on the principle of N−1, along with the comprehensive comparison method oriented by social benefits, serves as the foundation for planning and layout, then a scientific and systematic approach to natural gas pipeline network planning is established. The planning enables effective investment to play a key role while ensuring national energy security and meeting public gas demand. Additionally, it aims to reduce energy consumption in pipeline operation and offers guidance for medium- and long-term planning and construction decisions for the natural gas trunk pipeline network.