Scenarios for Potential Impacts from Hypothetical Leakage from CO₂ Geological Storage Facilities

As a contribution to the European RISCS project, Quintessa staff have authored a report on scenarios for potential impacts that might be caused by hypothetical carbon dioxide leakage from geological storage facilities.

The RISCS project is running for 4 years (2010 - 2014) and is supported by the European Commission and a number of industrial partners. The project aims to improve understanding of how geological CO2 storage might possibly impact upon the environment. There are 24 participating organisations, including research institutions, industrial companies, environmental associations and the International Energy Agency Greenhouse Gas R & D Programme.

Facilities for the geological storage of CO2 as part of carbon capture and storage (CCS) schemes will be designed to prevent leakage back to the surface.  However, it is important to be able to assess the consequences of any such leakage should it occur, as recognized by the EC Directive on CO2 storage and other sources of guidance such as the OSPAR Framework, USEPA Vulnerability Evaluation Framework and the CO2QUALSTORE Guideline.

The report describes a set of reference European marine and terrestrial receptor environments together with associated generalised impact scenario descriptions.  The baseline ‘most likely’ scenario is for a storage system to evolve as designed, with no leaks occurring. In other words, potential receptors, such as organisms and groundwater resources, will evolve as they would in the absence of any CO2 storage project. In contrast 'impact' scenarios are  potential low likelihood 'alternative evolution' scenarios. Based on simplified scoping calculations and a review of published literature concerning natural CO2 seepages and modelled CO2 behaviour, illustrative CO2 leakage fluxes and areas that would be plausible for the alternative leakage scenarios are presented.