Carbon capture technology and how it works – National Grid

1. Carbon sinks

Natural forms of CCS are called carbon sinks and they are vast spaces where the natural habitats capture CO2 from the atmosphere these include forests, oceans, grasslands and wetlands.

Scientists, as well as environmental and conservation experts, recognise that the preservation and cultivation of carbon sinks could increase the amount of carbon taken from our atmosphere in the shortest space of time.

Grasslands and wetlands in particular have a much quicker turnaround for carbon storage, with coastal wetlands storing more carbon per hectare than other habitats like forests.1

Where woodland is used, experts believe certain types of tree - such as birch or willow are optimal for land-based carbon capture as they absorb more CO2 comparatively than other tree species.

One way were working to biologically capture carbon is by preserving and rehabilitating an ancient peat bog located close to one of our substations in South Wales.

The 15-hectare bog stores the equivalent of 32,000 tonnes of carbon dioxide, which is equal to the average annual emissions of 22,000 petrol cars. Restoring it has also provided conditions for rare butterflies and vegetation to flourish.

Deep saline aquifers are underground geological formations; vast expanses of porous, sedimentary rock, which are filled with salt water. CO2 can be injected into these and stored permanently in fact, saline aquifers have the largest identified storage potential among all other forms of engineered CCS.

The Endurance aquifer, located in the North Sea off the coast of the UK, is one such formation, which sits approximately 1 mile (1.6km) below the sea bed. Roughly the size of Manhattan Island and the height of The Shard or the Empire State Building, its porous composition allows for carbon dioxide to be injected into it and stored safely for potentially thousands of years.

In the US, multiple large-scale saline aquifers are now being used for CCS purposes, such as the Citronelle Project in Alabama. During its three-year trial period, it was successful in storing more than 150,000 tonnes of CO2 per year, which was captured from a nearby pilot facility.

Carbon capture technologies are still being developed globally, with individual countries creating strategies that respond to their own net zero goals. For example, in China companies have developed experimental commercial air filters huge towers that clean air of pollutants on a huge scale. These giant air towers purify air by drawing it into glass rooms, which are heated using solar power creating a greenhouse effect. This hot air up is pushed up the tower through a series of filters, before being released back into the atmosphere as clean air.

One such giant air-purifier tower in Xian has reportedly been cleaning more than 353 million cubic feet of air each day, dramatically improving local air quality. Manufacturers believe they are close to developing even larger towers, where just one could clean enough air on a daily basis for a small city.

The most recent advancements in CCS technology includes new types of liquids, which are highly effective at absorbing CO2. Two dimensional ionic liquids have a molecular structure that allow for higher rates of CO2 to be absorbed. Scientists believe editing liquids can offer more precise control in the chemical engineering process and are considered environmentally friendly.

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Carbon capture technology and how it works - National Grid