Today, CCS projects are storing almost 45 million tons of CO2 every year, which is about the amount of CO2 emissions created by 10 million passenger cars. Capture generally takes place at large stationary sources of CO2, like power plants or industrial plants that make cement, steel, and chemicals. Most current carbon capture projects use a liquid to chemically remove the CO2 before it goes out the smokestack, but several new types of capture processes are under development.

The captured CO2 gas is then compressed so it becomes liquid-like and transported to a storage site, generally through a pipeline. Ship transport is more expensive than using pipelines, but it is being considered in both Europe and Japan. Once at the storage site, the CO2 is pumped more than 2,500 feet down wells into geological formations like used-up oil and gas reservoirs, as well as formations that contain unusable, salty water.

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.

Saline Aquifers

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.

Giant Air Filters

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.