CCS is a chain made up of multiple technologies that aim to reduce emissions into the atmosphere by capturing and storing large amounts of CO2 permanently. This process can be divided into three main phases: capture, transport and storage. 

 

Another phase, also considered when talking about CCS (in this case, called CCUS) is the use of CO2, but the latter is considered an alternative phase to permanent storage.

 

MAIN PHASES:

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• Capture- The process begins with the separation and capture of CO2 from gaseous mixtures, mainly from   highly emitting sources, such as electricity generation plants, biofuel production and industrial processes.   capture methods can be classified into three groups, according to the way and stage in which CO2 separation occurs: post-combustion, pre-combustion and oxy-combustion. For processes in which fossil fuels are burned, such as in thermoelectric plants, for example, post-combustion capture is used. In processes related to bioenergy, however, capture by pre-combustion, such as gasification, is promising.

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• Transport- Once this CO2 is separated and captured, it is compressed and transported to the storage location. Transport options vary according to the distance between the capture location and the storage location, the availability of transport modes, among other factors. This transport can be carried out by means of gas pipelines (in a similar way to natural gas pipelines), ships or tank trucks. Brazil, for example, still does not have the infrastructure for CO2 pipelines.

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• Storage– After  transported, the CO2 is injected underground, usually at depths greater than 800 m, to be stored in rock formations – such as depleted oil and gas reservoirs (those reservoirs that have already been explored) , deep layers of coal, deep saline aquifers, among others. The selection of storage sites depends on a careful geological assessment that identifies sites that meet all the technical conditions to ensure that CO2 remains safely underground for thousands of years.