Matching CO2 large point sources and potential geological storage sites in mainland Portugal

Abstract

Fossil fuel combustion is the major source of the increasing atmospheric concentration of carbone dioxide (CO2) since the pre-industrial period. Combustion systems like power plants, cement, iron and steel production plants and refineries are the main stationary sources of CO2 emissions. The reduction of greenhouse gas emissions in one of the main climate change mitigation measures. Carbon dioxide capture and storage (CCS) is one of the possible mitigation measures. The objective of this study was to analyze the hypothesis for the implementation of CCS systems in mainland Portugal based on source-sink matching. The CO2 large point sources (LPS) considered in mainland Portugal were the largest installations included in the Phase II of the European Emissions Trading Scheme with the highest CO2 emissions, representing about 90% of the total CO2 emissions of the Trading Scheme, verified in 2007. The potential geological storage locations considered were the geological formations formerly identified in existing studies. After the mapping of LPS and potential geological sinks of mainland Portugal, an analysis based on the proximity of the sources and storage sites was performed. From this it was possible to conclude that a large number of LPS are within or near the potential storage areas. An attempt of estimating costs of implementing a CCS system in mainland Portugal was also performed, considering the identified LPS and storage areas. This cost estimate was a very rough exercise but can allow an order of magnitude of the costs of implementing a CCS system in mainland Portugal. Preliminary results suggest that at present CCS systems are not economically interesting in Portugal, but this may change with increasing costs of energy and emission permits. The present lack of information regarding geological storage sites is an important limitation for the assessment of implementing a CCS system in mainland Portugal. Further detailed studies are required, starting with the characterisation of geological sites and the candidate sources to CCS, from technical aspects to environmental and economical factors.