Final Report Summary of the European Union Project Research into Impacts and Safety in CO2 Storage: Final OGS-DOGA Oceanographic Results

Effects assessment – based on the sensitivity of particular species, communities or habitats linked to potential leakage events associated with identified risks. Where relevant it shall include effects of exposure to elevated CO2 concentrations in the biosphere (including soils, marine sediments and benthic waters (asphyxiation; hypercapnia) and reduced pH in those environments as a consequence of leaking CO2).. There are limitations in regard to quantitative approaches as follows: Research on quantification of leakage pathways and flux rates is still ongoing, and therefore these assessments are likely to be of qualitative/semi-quantitative nature, until experienced is gained. Further research studies are underway, with an aim to provide more quantitative approaches/data for such assessments. See, for example, 'IEAGHG Quantification Techniques for CO2 Leakage' study and the EU FP7 RISCS project. It is recognised that current imaging technologies should be further developed to identify the existence of all relevant risks, as the scale of some risks could be less than existing surveying detection limits. Judging the likelihood and consequence of risk elements, or the associated uncertainties, both qualitatively or (semi- )quantitatively, depends in part on the reliability of the input parameters. Care should be taken that a valid body of data and experience exists for justifying the application of quantitative analysis to risk elements affecting the geological storage of CO2. (European Commission Guidance Document 1 Excerpts, pages 39-40)