What is CCS?

Carbon Capture and Storage (CCS) is a group of technologies that can remove almost 100% of the carbon dioxide from large-scale point sources of carbon such as energy intensive industries (for example steel, cement and refining) and fossil fuel power.

When combined with natural gas, CCS can also produce low-carbon hydrogen which can then be used to remove emissions from domestic and industrial heating.

CCS can also be used with bioenergy (bio-CCS or BECCS) as a negative emissions technology, which can actually remove carbon dioxide from the atmosphere.

There are several large-scale CCS projects already in operation around the world such as the Statoil Sleipner project, the SaskPower Boundary Dam project and the Shell Quest project.

 

CCS is a three-stage process:

Capture

The first stage in the CCS process is the capture of carbon dioxide from industrial processes such as steel-making, cement, chemicals and refining as well as capturing carbon dioxide from the gases involved with burning fossil fuels for electricity.

Capture technologies fall into three different categories; pre-combustion, post-combusion and oxy-fuel combustion.

Capturing carbon dioxide is not new technology – in fact, it has been carried out in the chemical industry since the 1940s

 

Transport

Once captured, the carbon dioxide is transported by pipeline or ship to a suitable storage site. The technologies involved in pipeline transportation are the same as those used extensively for transporting natural gas, oil and many other fluids around the world.

Laying the CO2 pipeline at SnøhvitIn some cases it may be possible to re-use existing but redundant pipelines.

Where pipelines can be shared by a number of different industries, there is the potential to develop CCS ‘clusters’. Such clusters represent the lowest-cost route to delivering CCS and reducing emissions across energy intensive industries and power.

Transportation of carbon dioxide has been carried out for over 40 years (particularly in the US for use in Enhanced Oil Recovery).

There are currently 7,762 km of operational carbon dioxide pipelines around the world.

Above: Laying the CO2 pipeline at Snøhvit. Courtesy of Statoil

 

Storage

Once the carbon dioxide has been transported, it is safely and permanently stored in geological formations that are typically located several kilometres below the earth’s surface (in the UK, carbon dioxide will be stored under the seabed). Suitable storage sites include depleted oil and gas fields and deep saline formations (porous rocks filled with very salty water).

Carbon dioxide can also be used for enhanced oil and gas recovery, where it is injected into near-depleted oil and gas fields to increase production. Any oil or gas that is recovered through this method would otherwise not be extracted and therefore has an economic value, which can help to offset some of the costs of carbon dioxide storage.

There is already considerable experience with injecting carbon dioxide deep underground for storage. For example, the Statoil Sleipner project has safely stored over 17 million tonnes of carbon dioxide since 1996. And there is more than 40 years of experience with injecting carbon dioxide for use in enhanced oil and gas recovery.

The UK has a large amount of storage capacity at its disposal, particularly under the North Sea. See CCS in the UK.

 

Above: Diagram showing how CO2 is stored underground – Image courtesy of Statoil