Multiscale analysis for the utilization of CO2 towards the production of chemicals at the country level: Case study of Spain

Abstract

This work evaluates a systematic comparison between the production of methanol and methane using CO2 and renewable hydrogen. CO2 is captured from point and dilute sources using aqueous MEA solutions and a conventional DAC process. Hydrogen is obtained through water electrolysis, powered by PV panels and wind turbines. First, a techno-economic evaluation is developed to detail the characteristics of the production facilities and the renewable energy systems. Finally, a Facility Location Problem (FLP) is developed to determine the centralized and decentralized CO2 use across Spain. This supply network is formulated as a mixed-integer linear programming (MILP) problem, selecting the optimal amount of CO2 to capture, the number and location of the facilities, the distribution of the PV panels for a fixed available area in the territory, and the number of wind turbines across the 47 Spanish peninsular provinces. Methanol is the selected product, with prices between 1,000–2,600 €/tMethanol. MEA solutions are preferred over DAC. Methane production is also considered through decentralized CO2 capture due to abundant CO2 availability and high transportation costs. A sensitivity analysis was performed, obtaining prices from 18.97 to 20.36 €/MMBTU to 8.90–9.09 €/MMBTU in the years 2022 and 2050, covering 5 times the methane production for that period. The implementation of carbon taxes could lower methane prices to around 2–3 €/MMBTU by 2050, aligning closely with natural gas prices.