Carbon capture, utilization and storage spillover effects on the Portuguese energy system

Carbon capture, utilization and storage scenarios have been developed for the Lusitanian Basin (Portuguese region) under the STRATEGY CCUS project, considering Portugal's carbon neutrality goal up to 2050. Supported by the national energy policy vision, the scenarios assume the use of captured biogenic CO2 emissions to generate synthetic methane as well as the geological storage of fossil CO2. Although carbon capture, utilization and storage tackles CO2 emissions, while maintaining fuel combustion and industrial processes, the deployment of the technology may lead to side effects on the overall energy system, such as on renewable power generation necessary to produce synthetic fuels. This study analyses the spillover effects (i.e., the impacts) of carbon capture, utilization and storage in the Lusitanian Basin in the Portuguese energy system, namely in the national power capacity and final energy consumption. The analysis is supported by the linear optimization energy system model TIMES_PT. Results show that by 2050, the generation of synthetic methane by hydrogen from electrolysis and CO2 (e-gas) demands a large amount of green hydrogen, 29% more than compared with a cost-effective decarbonization scenario. Consequently, a higher installed power capacity of solar and wind (above 6 GW by 2050) will be required. Contrary to what would be expected, the mandatory generation of e-gas does not lead to a reduction in electricity consumption in final users, as the synthetic fuel substitutes instead biomass/biogas and the direct use of hydrogen.