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CO2 capture, use, and storage (CCUS)

CO2 capture technologies used by Repsol

CO2 capture, use, and storage (CCUS) is an innovative technology key to achieving our atmospheric CO2 reduction targets. At Repsol, we lead the implementation of CCUS solutions to mitigate industrial emissions, transforming CO2 into a raw material or storing it for future uses.

What is carbon capture, use, and storage?

Carbon capture, use, and storage (CCUS) technologies are what we call the set of technological processes that seek to reduce the amount of CO2 in the atmosphere by capturing and storing it safely for future use. Not only does CCUS offer an additional solution to gas reduction policy, it can also be used in hydrocarbon recovery processes and other future uses currently under development. 

CCS (carbon capture and storage)

These technologies allow carbon dioxide emissions to be captured and stored safely in the subsoil, preventing them from being released into the atmosphere.

The capture is usually done directly from the emitting sources (more efficient) or CO2 can be extracted  directly from the atmosphere. In the latter case, it is called Direct Air Capture (DAC).

CCU (carbon capture and use)

If the carbon is used to develop other products instead of being stored in the subsoil, it is called carbon capture and use (CCU).

CCUS

A term for referring jointly to CCS and CCU.

What carbon capture technologies (CCUS) can do

They contribute to the reduction of CO2 emissions

They allow the reconversion of waste into raw material

They are safe for people and the environment

They are applicable in large industrial sectors

CCS technologies: efficiency in industry

Strong track record

The techniques used in CCS are proven technologies that have been used for decades on a commercial scale, with over 620 CCS projects in various stages of development worldwide (as reported by the Global CCS Institute, 2025). Thus, CO₂ storage is considered completely safe for people and the environment, as demonstrated by the track record of success for more than five decades. 

Adapting to change

Although CCS has a strong track record, its large-scale application poses new technological challenges. In the beginning, it worked with relatively small volumes of CO₂, but today it aspires to manage quantities on the order of gigatons, which requires redesigning infrastructures and processes to make them more robust and efficient.

In addition, the origin of CO₂ has changed: previously it was obtained mainly from the subsoil, while now it comes from industrial sources, which introduces impurities into the captured gas. These impurities can affect their behavior during transport, injection, and storage, generating phenomena such as corrosion, solid formation, or changes in pressure and temperature. 

Upstream: the best prepared sector

The technical and scientific knowledge accumulated by upstream companies positions this sector as the best able to face these challenges. Thanks to their experience in subsoil fluid management, well design, and geological risk management, Upstream companies are consolidated as guarantors of the safe and effective deployment of these technologies, ensuring the injection and permanent storage of CO₂.

CCU: unlocking the CO2 value chain

Capture and use

Once carbon dioxide (CO₂) is captured, rather than stored geologically, it can be transformed into a wide range of useful products through various technological routes.

This use of CO₂ not only reduces emissions but also converts a waste into a raw material for sectors such as construction, energy, chemicals, and food.

There are six broad categories of CO₂ -derived products:

  • Synthetic fuels.
  • Chemicals.
  • Polymers.
  • Construction aggregates.
  • Carbon additives.
  • Ingredients.

Each of these categories has specific by-products and compatible conversion routes, such as mineralization, biological conversion, electrolysis, photocatalysis, and thermal catalysis.

Reconversion of CO2 into raw materials

CO₂ can also be converted into synthetic fuels such as e-methanol or e-diesel, by thermochemical, electrochemical, or biological processes.

These fuels are chemically equivalent to their fossil counterparts and can be integrated into existing infrastructure, making them especially attractive for sectors that are difficult to electrify, such as aviation, maritime, or heavy-duty road transport.

CO₂ can also be transformed into basic chemicals and intermediates that serve as product synthesis building blocks for a wide range of industries, from petrochemicals, pharmaceuticals, to materials.

Among the most prominent compounds are ethylene and propylene, carbon monoxide, and formic acid, which can be obtained through routes such as thermal catalysis, electrolysis, or biological conversion.

These chemicals can be integrated into existing value chains, substituting fossil raw materials and thus reducing the carbon footprint of key industrial processes.

The production of chemicals from CO₂ is emerging as a strategic way to reduce emissions in the chemicals industry without compromising its competitiveness.

Construction aggregates are another of the most promising destinations for captured CO₂, due to their ability to act as a permanent carbon sink. In this case, CO₂ is used to cure concrete mixtures or to mineralize industrial waste such as fly ash or slag, generating materials such as aggregates or supplementary cements.

CO2 storage tanks

FAQs about carbon capture, use, and storage (CCUS)

Captured CO2 is a versatile raw material in the circular economy. Its main uses include: 

  • Synthetic fuels (e-fuels): combining it with renewable hydrogen to create net-zero emission fuels. 
  • Building materials: to make cements and concretes that sequester carbon permanently. 
  • Chemical industry: production of sustainable polymers and plastics. 

The difference lies in the final destination of the carbon: 

  • CCCS (capture and storage): focuses exclusively on capturing CO2 and confining it underground to remove it from the atmospheric cycle. 
  • CCUS (capture, storage, and usage): Just add the U for "use." Here, CO2 is reintroduced into the value chain to make products, fostering the circular economy and reducing dependence on fossil sources. 

Repsol has integrated CO2 as a strategic resource. At our industrial complexes, the company undetakes projects to combine captured CO2 with renewable hydrogen. The resulting products are low-carbon e-fuels or liquid fuels, which make it possible to decarbonize sectors that are difficult to electrify, such as aviation or heavy transport. 

Learn more about these technologies

Petronor industrial complex

First synthetic fuels plant in Spain

We are committed to a circular model where we use renewable CO2 and  H2 to produce synthetic fuels.

Eco-aggregates

CO2 mineralization project

We are promoting the reuse of waste by converting it into new raw materials that we reintroduce back into production cycles.

Updated as of May 2026