Frequently asked questions
1. Does CCS capture all the carbon dioxide from a flue gas?
So far, we know CCS plant can achieve capture of ~95% of carbon dioxide in flue gases. This leaves 5% of carbon emissions that will need offsetting in order to meet net-zero GHG emissions. The technology is developing so this could change or depend on the composition of the flue gas the CCS plant processes.
2. Can we achieve net-zero without CCUS?
The climate change committee (CCC), an independent statutory body established to advise the UK governments on climate change, say carbon capture is an essential component of the UK’s decarbonisation journey. However, it is not the only technology needed to decarbonise our whole economy. More information about decarbonisation and the role of CCUS can be found the CCC’s 6th carbon budget for the UK and the Scottish Emissions Targets – 2022 five yearly review.
3. Can we fit CCUS to all sources of carbon dioxide in order the meet our GHG reduction commitments and beat climate change?
Currently it is more likely CCS will be appropriate for industrial operations with significant carbon dioxide emissions. This is because the process require energy to run and also the carbon dioxide needs to be gathered and transported to an underground storage location. For other sources of GHG gases, like home boilers or cars, different solutions will likely be needed to meet net-zero GHG emissions.
4. Is CCUS dangerous or harmful?
Environmental regulations are in place to protect the environment and human health, so the impact of any potentially polluting substances used in a CCS plant will be managed via the PPC permit. This can include limits on emissions to air, land and water, it may also include requirements to used best available techniques to manage any impacts to an acceptable level for human health and the wider environment.
5. Is direct air capture a type of CCUS?
Yes, direct air storage is a type of CCUS. Rather than separating CO2 from a flue gas or process emissions as in industrial CCS, direct air capture separates CO2 from the air. The proportion of carbon dioxide in air is much less then in flue gases or process emissions, so direct air capture usually needs more energy and more space than industrial CCUS applications.
6. Which is better storage or utilisation?
Ultimately, to have the most benefit to our climate the carbon dioxide should be stored (not emitted to the atmosphere) permanently. Some type of utilisation only temporarily avoids emitting the carbon dioxide to the atmosphere. While this might displace another source of CO2 it might also create a demand (and therefore increase emissions of CO2) so utilisation needs to be considered very carefully before we can confidently say it could contribute to delivering GHG emissions reductions.