Once the CO2 is captured, it is then compressed and transported to be permanently stored in geological formations underground (e.g. saline aquifers, oil reservoirs), or used to create products such as concrete and low-carbon synthetic fuels.
CCUS technologies can deliver negative emissions by removing CO2 from the air (direct-air-capture) or from biomass-based energy and storing the CO2.
CO2 capture is an integral part of several industrial processes and, accordingly, technologies to separate or capture CO2 from flue gas streams have been commercially available for many decades.
The most advanced and widely adopted capture technologies are
- chemical absorption and physical separation
- membranes and looping cycles such as chemical looping or calcium looping
Today arund 230 Mt of CO2 are used globally each year, primarily to produce fertilisers (around 125 Mt/year) and for enhanced oil recovery (around 70-80 Mt/year).
Other commercial uses of CO2 include food and beverage production, cooling, water treatment and greenhouses.
The IEA has made clear that these net-zero goals will become virtually impossible to meet without CCUS.
Their Net-Zero to 2050 Roadmap indicates that driving down emissions to net-zero would require 7.6 Gt of CO2 to be captured globally – which is 190 times more than today.