CCS- carbon dioxide capture and storage

Fossil fuels (mainly coal powered power stations) emits about one-third of all carbon dioxide (CO₂) that goes to the atmosphere every day. As it’s a well-known greenhouse gas, therefore many attempts are being made to capture it from the power stations and to store it underground in the geological formations. The aim is therefore towards ‘zero emission’.

Energy companies like Vattenfall are now moving ahead towards a cleaner production of power. The company has a 30 MW thermal pilot plant at Schwarze Pumpe in Germany. Here’s what Vattenfall do about CO₂ –

Lignite and hard coal will be combusted in a mixture of oxygen and re-circulated CO₂, which also contains water vapour. The flue gas will then be treated and sulphuroxides, particles and other contaminants removed. Finally, the water will be condensed and the concentrated CO₂ compressed into liquid. The captured CO₂ will then be stored underground.

Risk. Will the injected CO₂ remain safely underground or will it leak back to the atmosphere?

It’s still a matter of intensive research. If CO₂ leaks from the storage reservoir and when it comes in contact with groundwater it can form carbonic acid (H₂CO₃) which can lower the pH or cause much acidity in the surrounding environment. It can have a variety of consequences based on the chemistry of the contact materials. It can dissolve heavy metals and deteriorate the water quality drastically. More strategic environmental assessment from Vattenfall.

Therefore research and development is ongoing in this field as it’s the burning issue now. Currently we are at the infant stage of carbon dioxide capture and storage.