Capture and storage of CO₂

Emission of CO₂ into the atmosphere: a problem still present in 2030

•  The Kyoto Protocol, one of the components of the United Nations Framework Convention on Climate Change (UNFCC), aims to reduce greenhouse gas (GG) emissions in the industrialised countries by 5.2% in 2012 compared to their level in 1990. One of the principal greenhouse gases, designated as being responsible for global warming, is carbon dioxide (CO₂).

•  At the present time, improvement in energy efficiency (that is to say, a reduction in the energy consumed to provide a given service or to carry out a given task), as well as the use of renewable energy sources, are in the frontline of the fight against increases in CO₂ concentration in the atmosphere. Unfortunately, the most likely scenario for the future is that, by 2030, the demand for energy will still be increasing and that 80% of the total will continue to be met by the use of fossil energy sources, emitting CO₂. According to figures from the International Energy Agency (IEA), CO₂ emissions will be in excess of 37 billion tonnes annually by 2030, compared with 23 billion tonnes per year at the present time. It is therefore vital to find new ways of combating CO₂ discharges.

One possible answer: geological sequestration of CO₂

•  The technologies of geological sequestration, or confinement, of CO₂ have seen a revival of interest in recent years. They involve capturing the CO₂ at source, as soon as it is discharged, then trapping it in a geological structure, on land or at sea. If it were possible, in this way, to capture the CO₂ and store it for several centuries, it would be conceivable to envisage putting off its discharge into the atmosphere until a time when the use of fossil-based energy would be a thing of the past and greenhouse gas emissions would no longer be at a critical level.

•  According to the IPCC (Intergovernmental Panel on Climate Change), this technique could deal with 20 to 40% of worldwide CO₂ emissions by 2050, contributing 10 to 15% of the effort to reduce emissions by 2100.

•  However, attaining such objectives, involves taking up two major challenges: one technological, the other economic. Methods of capturing and storing CO₂ have not yet been totally perfected and they still require large inputs of energy, resulting in heavy costs.