Simple Explanation of Technologies that Capture or Remove Carbon

Along with reduction and adaptation, technologies that remove carbon from the atmosphere or capture it at source are the third pillar of climate action. These technologies (sometimes called negative emissions technologies or NETs) can be broadly subdivided into carbon dioxide removal (CDR), also known simply as carbon removal (CR), which removes CO2 from the air, and carbon technologies (carbon tech), which remove carbon from source emissions.

Once the carbon is either captured or removed it can be kept out of the atmosphere in a process known as sequestration. One of the most effective approaches to carbon sequestration involves leveraging the CO2-absorbing characteristics of different types of rock. Geosequestration is a long-term solution for the storage of carbon, it locks emissions away underground.

Carbon capture (CC) separates CO2 from the source where emissions are produced preventing them from entering the atmosphere. Carbon capture, and sequestration (CCS) removes and transports captured carbon to sequestration sites.

Captured CO2 can also be ‘locked away’ in manufactured products through what is known as CCU which uses captured CO2 to make everything from fuel to bulletproof vests. In the fossil fuel industry a type of CCU, known as CCUS (carbon capture utilization and sequestration) uses captured CO2 to extract more oil and gas from a well through a process known as enhanced oil recovery (EOR).

Rather than siphon carbon from the source where they are produced, CDR removes carbon from the air, this includes direct air capture or DAC sometimes referred to as DACCS (direct air capture with carbon storage), and natural climate solutions (NCS) also known as nature-based climate solutions. NCS leverages natural processes like photosynthesis, to remove carbon from the air. Although NCS is great at capturing carbon, it does not always sequester that carbon over long periods. NCS is prone to carbon losses from events such as wildfires, drought, marine heat waves, and insect infestations. DAC/DACCS is a carbon removal solution that uses machines with fans that push air through chambers that remove CO2.  

These different carbon capture/removal technologies all have a role to play as they are part of a suite of widely recognized climate solutions. These technologies are often assessed by their viability, scalability, and cost. There are a host of novel ways of removing carbon and a wide range of research directions are being explored.

Related

• How 3 Carbon Removal Technologies Work Together to Mitigate CO2
• We Need a Master Plan to Remove Carbon

Related videos and podcasts

• Video: Primer on Carbon Removal Technologies
• Podcast: Richard Matthews Discusses Carbon Removal

Related research

• Why We Need Carbon Capture and Sequestration
• Evaluation Criteria to Assess Carbon Removal Technologies  
• Assessment of Carbon Capture Technologies
• Assessment of Leading Carbon Capture Companies

Fossil fuels and carbon capture

• The Role of the Fossil Fuel Industry in Carbon Capture
• What We Should and Should Not Do with Captured Carbon
• The Fossil Fuel Industry’s Carbon Capture Ruse at COP 28

Cost and scalability of carbon capture

• The Economic Opportunities Associated with Carbon Removal
• The Costs of CDR (Carbon Capture, Direct Air Capture and Geosequestration)
• The Costs and Scalability of Carbon Capture Technologies