Multi-time scale CCUS pipeline network optimization: modeling cost-effective emission reduction trajectories by multi-policy integration

As global climate change escalates, curbing greenhouse gas emissions has emerged as a shared imperative and pressing necessity for the global community. Recognized as a critical decarbonization mechanism, carbon capture, utilization and storage (CCUS) systems require source-sink matching optimization to maximize their carbon sequestration potential. However, current research on source-sink matching predominantly focuses on a single dimension of space, time, or policy, lacking an integrated consideration of these three dimensions. Based on this, and in combination with the regional emission reduction requirements, a mixed-integer linear programming (MILP) framework was developed to enable carbon quota trading among sources. The model took into account not only the economy of CCUS technology but also its flexibility and adaptability during the multi-period construction process. The study divided the CCUS pipeline network into multiple construction periods and formulated differentiated emission reduction targets and policies for each. The aim was to optimize the network layout, considering time, space, and policy dimensions, to maximize emission reduction benefits and minimize costs. Case study verification revealed that, without considering carbon trading and carbon taxes, the total project cost increased yearly from 1.42 × 10⁹ USD in period u1 to 8.23 × 10⁹ USD in u8, with a marginal emission reduction cost of 35.64 USD/t. In contrast, when carbon tax and trading mechanisms were incorporated, the total cost still rose (from 1.08 × 10⁹ USD in u1 to 5.32 × 10⁹ USD in u8), but the marginal cost decreased by 21.12 % to 182.29 USD/t. This demonstrates the effectiveness of the proposed multi-period adjustment method and the synergistic role of policy integration in reducing decarbonization costs.