Carbon Capture, Usage and Storage (CCUS)

- Carbon Footprint

A carbon footprint is the total greenhouse gas (GHG) emissions caused by an individual, event, organization, service, place or product, expressed as carbon dioxide equivalent. Greenhouse gases, including the carbon-containing gases carbon dioxide and methane, can be emitted through the burning of fossil fuels, land clearance and the production and consumption of food, manufactured goods, materials, wood, roads, buildings, transportation and other services.

- Carbon Neutral and Net Zero

Carbon neutrality refers to achieving net-zero carbon dioxide emissions. This can be done by balancing emissions of carbon dioxide with its removal (often through carbon offsetting) or by eliminating emissions from society (the transition to the "post-carbon economy"). It is used in the context of carbon dioxide-releasing processes associated with transportation, energy production, agriculture, and industry. 

Although the term "carbon neutral" is used, a carbon footprint also includes other greenhouse gases, usually carbon-based, measured in terms of their carbon dioxide equivalence. The term climate-neutral reflects the broader inclusiveness of other greenhouse gases in climate change, even if CO2 is the most abundant. The term "net zero" is increasingly used to describe a broader and more comprehensive commitment to decarbonization and climate action, moving beyond carbon neutrality by including more activities under the scope of indirect emissions, and often including a science-based target on emissions reduction, as opposed to relying solely on offsetting.

- Overview - CCUS Technology

Carbon Capture, Usage and Storage (CCUS) is a technology that can capture and make effective use of the high concentrations of CO₂ emitted by industrial activities. Consequently, it has a key role to play in decarbonization and the addressing the challenge of global climate change. 

The capture, transport and utilisation or storage of CO2 as a successful mitigation strategy hinges on the availability of technologies at each stage of the process as well as on the development and expansion of CO2 transport and storage networks. All of the steps along the value chain need to be technologically ready and developed in tandem for CCUS to scale up. 

CCUS technologies are at varying levels of maturity today. Several technologies in CO2 capture, transport, utilisation and storage are already deployed at large scale, but other technologies, including those that hold out the promise of better performance and lower unit costs, require further development. One way to assess where a technology is in its journey from the laboratory to the marketplace is to use the Technology Readiness Level (TRL) scale, which provides a common framework that can be applied to any technology to assess and compare the maturity of technologies across and within different sectors. 

- CCUS Technology Readiness Level (TRL) Scale

Originally developed by the United States National Aeronautics and Space Administration (NASA) in the 1970s, the TRL provides a snapshot in time of the level of maturity of a given technology within a defined scale. It is now widely used by research institutions and technology developers around the world to set research priorities and design innovation support programmes. 

The scale, which ranges from 1 to 9, can be applied to any technology. However, arriving at a stage where a technology can be considered commercially available (TRL 9) is not sufficient to describe its readiness to meet energy policy objectives, for which scale is often crucial. For this reason, the IEA has extended the TRL scale used in this report to incorporate two additional levels of readiness: one where the technology is commercial and competitive but needs further innovation efforts for the technology to be integrated into energy systems and value chains when deployed at scale (TRL 10), and a final one where the technology has achieved predictable growth (TRL 11). 

- The Four CCUS TRL Readiness Categories

The TRLs are grouped into four broader readiness categories: prototype, demonstration, early adoption and mature. All of the CCUS technologies and CCUS value chains that are projected to play a role in the Sustainable Development Scenario before 2070 are already at least at the prototype stage. For more details, see IEA (2020a) and IEA (2020b). 

Mature for commercial technology types that have reached sizeable deployment and for which only incremental innovations are expected. Technology types in this category have all designs and underlying components at TRL 11. Hydropower and electric trains are examples. 

Early adoption for technology types for which some designs have reached market and require policy support for scale-up, but where there are competing designs being validated at the demonstration and prototype stages. Technology types in this category have an underlying design of TRL ≥ 9. Offshore wind, electric batteries and heat pumps are examples. 

Demonstration for technology types for which designs are at demonstration stage or below, meaning no underlying design at TRL ≥ 9, but with at least one design at TRL 7 or 8. Carbon capture in cement kilns, electrolytic hydrogen-based ammonia and methanol, and large long-distance battery-electric ships are examples. 

Prototype for technology types for which designs are at prototype stage of a certain scale, meaning no underlying design at TRL 7 or 8, but with at least one design at TRL 5. Ammonia-powered vessels, electrolytic hydrogen-based steel production and DAC are examples.
 

[More to come ...]