This is an excerpt from a speech given by Judith Hackett, the head of the Health & Safety Executive. Coming so soon after the news that CCS can cause earthquakes, one can't help but wonder if this is an idea that will now pass into obscurity
CO2 has for many years had a variety of applications in industrial processes. But CCS brings these processes together on a completely different scale to capture the CO2 from fossil fuel burning power stations and then store it permanently under the sea in deep geological formations. The method involves several 'interfaces': capture, compression, transport, intermediate storage and injection into storage all of which need further understanding. The existing regulatory framework is sufficiently flexible to mean that it can cover the whole CCS process. But this still requires the risks to be identified and for the appropriate control and mitigatory measures to be implemented. A major release of pure CO2 into the atmosphere at any point in the process would present a major hazard as an asphyxiant.
But engineers must also consider:
- The effect of impurities in the CO2 stream;
- how will CO2 in the super-critical stage be managed given its potentially harmful properties as a powerful solvent?
- what materials of construction should be used for CO2, which could be impure, wet and therefore acidic and in varying thermodynamic states;
- how CO2 will behave if a pipe it's being carried in ruptures.
One simple but stark illustration of dealing with CO2 relates to escape routes for personnel on offshore platforms in the event of a CO2 release during the injection phase into deep sea storage. Traditionally, for the oil and gas sector, personnel evacuation down to sea level has been the right answer when dealing with the conventional threat of a loss of containment of oil and gas but CO2, is heavier than air and will - on a calm day - accumulate on the sea's surface rendering a marine response impossible.