Application of multicriteria algorithm to select suitable areas for storing CO2: CO2SiteAssess software

Abstract Deep saline aquifers are amongst the most promising emplacements for CO 2 storing, since theoretically these structures offer the highest value in terms of capacity, the risk associated with the exploration of these potential sites is greater than that for already investigated depleted oil or gas fields. In such cases, it is likely that multicriteria algorithms can facilitate the evaluation of the best alternative under consideration and the results from this process will, therefore, help the decision-maker in decreasing the risk associated with the exploration of these potential emplacements. Site selection phase comprises the identification, characterization and selection of emplacements which could be suitable for CCS among a list of candidates. In this article we propose a methodology based on (i) data recompilation and (ii) mathematical algorithm to define criteria and to hierarchy all of them in a quantitative methodology. Multicriteria decision tool could complement the collection of data: It is necessary to evaluate and to hierarchy each region or area, in order to improve the economic and technical efforts into CO 2 storage characterization. To make it possible, both technical and socio-economic criteria should be defined and weighted through a criteria ranking process. In order to help decision maker mathematical algorithm and hierarchy process has been implemented in software: CO 2 SITEASSESS is a program based on Visual Basic. It connects with a Data Base (CO 2 sources and storage alternatives), and it allows to compare different areas and structures, in order to hierarchy them or to compare with other projects (it easily might be used to standardize the site selection phase). Results can be implemented in a Geographical Information System, and it allows to geo-reference the alternatives. This tool has been used to evaluate different areas in Spain: The Guadalquivir basin in southern Spain. Five structures were defined, and the results showed that the methodology is useful to compare different alternatives, and the software may describe the criteria which need more accuracy (lack of data). In this case, the software helps project manager to define the characterization activities, in order to focus on those parameters which needs to be explored