Carbon Capture & Storage: what are the stakes?

CO2 is considered as one of the main causes of climate change. Two thirds of CO2 emissions come from fossil fuels used for power generation or from industrial processes as oil refineries, cement works, iron and steel production... The process of Carbon Capture & Storage could reduce substantially these CO2 emissions in the atmosphere.

How does it work?

Carbon is first captured, through separation from other gases produced. In the case of CO2 capture in power plants, several options can be chosen from: pre- combustion, post-combustion, or oxycombustion.

The CO2 is transported by ship or pipeline from the capture site to the storage site.

CO2 is then stored for hundreds of years into depleted Oil & Gas reservoirs, deep saline formations or unminable coal seams, either onshore or offshore.

What is the status of CO2 storage?

Storage of CO2 has taken place for many years within the framework of Enhanced Oil Recovery (EOR), but long-term CO2 storage for climate change reasons is relatively a new concept.

image Option for storage of CO2 Source: IEA-GHG, Putting carbon back into the ground,

Geological storage processes are under development in depleted Oil & Gas fields. Other geological options are studied in unminable coal seams or in deep saline aquifers. CO2 could also be stored into the deep ocean, but further research programmes are required to provide a better understanding of this technique.

Next steps for the development of CCS are cost reduction and acceptability improvement as a safe, reliable and long term containment of CO2. Since CO2 has been naturally stored for geological time-scales and many of the considered reservoirs have already stored gases and liquids for thousands of years, CCS appears to have a promising and bright future.