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Carbon capture, storage and utilisation

Explaining carbon capture, utilisation, and storage (CCUS)

CCUS is the process of collecting/capturing (C) waste carbon dioxide (C) and transporting it to a site, where it is either used (U) for alternative purposes or stored (S) in geological formations.
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15 November 2022
CCSU Whitepaper frontpage

White Paper: Carbon capture, utilisation, and storage

This article is part of the publication “Carbon capture, utilisation, and storage.

The content of this article was produced in close collaboration with DTU – Danish Technical University.

Download the publication

The purpose of CCUS is to prevent the release of large amounts of carbon dioxide (CO₂) into the atmosphere, but also to make biogenic CO₂ a valuable green commodity.

Today, carbon can be captured from the smoke from industries and from heat and power plants and waste-to-energy facilities, or it can be separated from biogas plants instead of being emitted into the air.

One way of capturing CO₂ is to conduct it through long pipes down to a liquid, which, among other substances, consists of additives that help absorb the CO₂ in the liquid. Once the CO₂ has been absorbed in the liquid, it can be separated and utilised for alternative purposes, or stored underground – onshore or offshore.

Storing CO2

Storing CO₂ is done by pumping the carbon into the many small cavities of the underground, while the above clay layer acts as a lid. As stated earlier, the Danish underground can store between 500 and 1000 years of the total Danish emissions at the current level.

CO2 utilisation

If the captured biogenic carbon is put to use, it can be synthesised into green fuels, which can fuel aircrafts and the maritime fleets of the future. When utilising the captured CO₂, the CO₂ is recycled and thereby prevents other emissions from fossil fuels. CO₂ is already a valuable commodity and today the world uses 230 million tonnes (Mt) of CO₂ from fossil fuel sources each year, according to the International Energy Agency.

Explaining CCSU

CCUS involves the capture of CO2 from large point sources, such as power generation or industrial facilities that use either fossil fuels or biomass as fuel. The CO2 can also be captured directly from the atmosphere. If not being used on-site, the captured CO2 is compressed and transported by pipeline, ship, rail or truck to be used in a range of applications, or injected into deep geological formations which can trap the CO2 for permanent storage.

What picking the high-hanging fruits means

When referring to picking the ‘high-hanging fruits’, it is because many of the ‘low-hanging fruits’ in the green transition have already been picked. Denmark has more than 50 years of experience doing just that. In particular in the sectors that can be retrofitted or directly electrified with relative ease.

CCUS is a key enabler of deep decarbonisation of the hard-to-abate sectors/the high-hanging fruits. They include transportation, agriculture, and heavy industry such as cement and chemical production.

Those who have the greatest prerequisites, hold the greatest responsibility. That is why Denmark and other countries are aiming to make CCUS a viable solution to meet global climate ambitions.

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Carbon capture, storage and utilisation