Carbon capture and storage

What is it?

Carbon capture and storage also known as sequestration, captures carbon dioxide from power stations and it stores it safely instead of letting the carbon dioxide be released into the atmosphere. This strategy is being seen as an immediate way of getting rid of waste carbon dioxide gas.

Where will the gas be stored?

The carbon dioxide being captured will be stored underground as the porous rock can act as a sort of sponge to store the gas. Old gas and oil fields are some of the best natural containers for this gas,the UK has many of these located in the North Sea.

How much carbon dioxide can be stored?

The UK can store about 10 years worth of the total UK carbon dioxide emissions in oilfields and a further 30 years worth in gas fields. It has been estimated that even when these fields have been filled that the UK has other porous rock capable of storing up to 500 years worth of carbon dioxide production.

Decarbonised fuels

At this moment in time power stations burn methane from natural gas as its fuel. This methane is obtained from gas fields. Carbon dioxide is produced and emitted into the atmosphere, this is how the greenhouse effect comes about.
To decarbonise fuel it has to be produced by reforming natural gas into a mixture of hydrogen gas and carbon dioxide. This process involves the use of well established technology already used by the oil industry.

This carbon dioxide will then be separated and piped offshore to an oilfield which is coming to the end of its useful life. It is extremely difficult to extract the remaining 30% of the oil the carbon dioxide being pumped into the oilfield. The carbon dioxide being pumped in will help the remaining oil to be extracted. The extra money earned from this helps to compensate the cost for decarbonising the fuel.

Storage as carbonates

Mineral storage aims to store carbon in stable minerals. Carbon dioxide is trapped by converting it into carbonate rock. In this process carbon dioxide is reacted with metsl oxides to produce stable carbonates.

This process does occur naturally and has produced the majority of our limestone rock as calcium carbonate but it is extremely slow and efforts to speed up are very energy intensive. A power station using mineral storage would require 60-180% more energy than a power plant without CCS. More research is required if mineral storage is to become a viable form of CCS.