Carbon Capture and Storage 

Carbon Capture and Storage (CCS) would allow power plants that run on fossil fuels – particularly coal-fired power stations - to continue operating with vastly reduced emissions. It could also be used to capture and store CO₂ from industrial processes that are large point source emitters, such as steel or cement producers.

Many of the components that are required for CCS are available today, but the end-to-end process has yet to be been demonstrated at scale. For example, Statoil has injected CO₂ into oil fields since the mid-1990s to enhance oil recovery (EOR), but the CO₂ used in this process is not sourced from power plants.

There are two main barriers to the deployment of large-scale CCS:

• Cost – capturing the CO₂ reduces the efficiency of power plants by ~20-25%, and transporting the CO₂ to storage sites through new pipeline infrastructure will be expensive
• Uncertainty about the reliability of storage – there is uncertainty as to how long CO₂ will stay under ground; it will be important to demonstrate to the public that CO₂ storage is safe and reliable.

Current research activities are focused on all the stages of the process:

Capture

• Pre-combustion capture - gasification of the fuel into hydrogen and carbon dioxide and then using the hydrogen to generate power
• Oxy-fuel combustion – combusting the fuel in pure oxygen to create a carbon dioxide stream that can be captured
• Post-combustion capture – capturing the CO₂ emitted in combustion through chemical absorption

Transport

Transporting the CO₂ to the storage site will involve building new infrastructure:

• Pipelines – to transport the CO₂ to the storage sites, both on- and off-shore
• Ships – to transport the CO₂ to offshore storage sites if no pipelines exist

Storage

There are a number of options for storing CO₂:

• Saline aquifers (rock formations which hold water) – the underground store with the largest potential capacity
• Depleted oil and gas fields – an alternative underground store with a potential capacity several times smaller than aquifers
• Enhanced Oil Recovery sites – a comparatively smaller-capacity underground store likely to be developed first since the CO^₂ injection improves the economics of the oil field; however, this benefit only lasts until the oil field is depleted, and some of the CO₂ is extracted with the oil

A number of pilot plants are in operation today to test carbon capture and storage, and large-scale demonstrators are planned in Europe, North America, Australia and China over the next 5 years.