MILP-BASED OPTIMIZATION MODEL FOR CO2 CAPTURE, TRANSPORT AND STORAGE (CCS) CHAIN PLANNING: APPLICATION TO THE HARD-TO-ABATE INDUSTRY IN ITALY

Carbon Capture and Storage (CCS) technologies emerge as a pivotal choice for decarbonization, especially in the context of the industrial sectors known as hard-to-abate, mostly represented by large point CO2 emitting facilities (i.e., producing more than 100 ktCO2/y).The full-scale CCS infrastructure deployment problem entails the optimization of all the steps of the chain that go from the carbon capture at the point of emission to the final storage site, through the appropriate transportation modes.Therefore, the design of the entire CCS chain features an intrinsic complexity that includes a multi-tier array of technological possibilities and routes that must take into consideration not only the techno-economic performance and economies of scale, but also practical constraints such as geographical limitations, the availability of modes of transportation, etc.In this work, a mixed-integer linear programming (MILP) optimization model, aiming at minimizing the cost linked to the implementation (installation and operation) of the CCS chain for a defined target of sequestration (e.g.10 MtCO2/y), is presented.The model is applied to the Italian case study, encompassing the major industrial carbon dioxide sources in the area: 15 cement plants, 4 refineries, 24 steel mills and 18 waste-to-energy plants.The set of variables span from capture technologies, with CAPEX and OPEX diversified by technology and sector, to transport modes selection, sizing and operation.Five possible modes of transportation have been considered: (i) barge, (ii) train, (iii) ship, (iv) truck and (v) pipeline.A single offshore storage site is hereby considered and located in the Adriatic Sea, nearby Ravenna.This comprehensive model enables the simulation and comparison of diverse scenarios that consider different targets of decarbonization and provides a flexible tool for policymakers to support the decision-making processes and the assessment of the evolution of a cost-effective chain over the long term, in harmony with the established net-zero target for 2050.The proposed scenarios take into consideration that in Italy: (i) for short-medium term targets, 1 to 10 MtCO2/y are aligned with the recently announced Callisto CO2 transport project and coherent with the PNIEC target; (ii) 20 MtCO2/y of CO2 abated could be reached by 2050 via CCS.