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Three Carbon Utilization Methods

The idea behind carbon utilization is that carbon dioxide (CO2) is a raw material that can be captured from industrial flue gas and then reused in a variety of commercially viable products and processes. It takes a different approach from merely storing CO2 underground, but the two methods are sometimes referred to together in the expression carbon capture, utilization and storage (CCUS).

The CO2 emitted by large industrial facilities (such as the coal-fired power plant shown here) can be utilized in a variety of physical and chemical processes. ©Thinkstock

Several CO2See Carbon Dioxid utilization methods have already achieved industrial maturity, including enhanced oil recovery (EOR), chemical synthesis and microalgae cultivation to produce high value-added products. However, these use only a very small amount of CO2: around 0.5% of global emissions, or less than 200 metric megatons per year (Mt CO2/year), compared with a total of more than 36,000 Mt CO2/year worldwide in 2015.

A great number of research projects in the field are currently being carried out around the world. Within the next 5 to 20 years, these could open up new prospects and eventually lead to the absorption of between 5% and 10% of emissions – provided reasonable solutions can be found to the cost issue.

0,5 % : The proportion of global CO2 emissions that are currently commercially utilized in industry.

 

CO2 utilization faces three underlying challenges:

 

  • Capturing carbon dioxide is a difficult and still costly process (see Close-Up: "Carbon Capture"). In addition, it can only viably be performed on extremely carbon-intensive industrial facilities, ruling out CO2 emissions from transportation, farming and housing. Carbon utilization is therefore just one of several drivers for bringing CO2 emissions under control, alongside other, more widely applicable solutions such as energy efficiencyIn economic terms, energy efficiency refers to the efforts made to reduce the energy consumption of a system..., energy savings, the development of renewable energies and underground storage.
  • Industrial facilities that use CO2 as a raw material must be located close to the source of emissions or face prohibitive transportation costs. For this reason, carbon utilization fits neatly into an approach based on the circular economy and eco-industrial parks, where the CO2 emissions from one plant become the feedstock for another.
  • CO2-based products must have existing commercial markets. These may be mass markets (such as for energy products), which are generally low value, or niche markets (such as for fine chemicals), which are high value but low volume.
  • The carbon footprintThe carbon footprint (also known as greenhouse gas inventory) of a good or service measures the impact human activities have on the environment ... of a process based on CO2 utilization must be smaller than that of the conventional alternative. In other words, CO2 emissions must be lower once the entire process cycle has been taken into account. Otherwise, the CO2 has merely been shifted along the chain before finally being released into the atmosphere. Consideration must also be given to the life cycle of the products before their destruction if the aim of the processing is to store carbon.

Around 50 metric megatons of CO2 per year are reinjected into oil wells to enhance recovery. 

Three main types of carbon utilization have been identified1: