New report on utilisation of captured CO2: - Mineralisation provides the best climate profile

The findings of a recent literature study show how captured CO2 should be used to minimise the climate footprint. The CCUS Norway business cluster network now hopes that the study can form the basis for further research and prioritisation in climate policy.

New report on utilisation of captured CO2

- The aim was to examine how different CCU routes perform environmentally and regarding resource efficiency, explains Ingunn Saur Modahl, senior researcher at NORSUS - Norwegian Institute for Sustainability Research.

Together with colleague and senior researcher Hanne Lerche Raadal, Modahl has written the report, which is part of the project "CCUS Verdiskapingspotensialet – næringsutvikling og innovasjon".

The research findings

The NORSUS researchers have looked at three different ways of utilising captured CO2, known as CCU (Carbon Capture Utilisation) routes:

• Mineralisation (e.g. into carbonates that can replace cement)

• Direct utilisation (e.g. for use in greenhouses)

• Chemicals and fuels

In the literature reviewed, the climate impacts are calculated using life cycle assessment methodology, which includes all burdens and benefits throughout the value chain. The most significant impacts are related to: 

• Electricity used for transforming CO2 and the climate profile of the potential substituted electricity

• Whether the CCU product replaces another product

• Whether the CO2 is permanently stored or released

- The report shows that CCU systems where CO2 is mineralised have the best climate performance. We are, however, aware that the results rely on a set of preconditions. For example, CCU fuel production can be a good option for transforming and storing renewable electricity in cases of surplus of electricity and when substituting fossil electricity generation is less relevant. If this is not the case, using renewable power to reduce fossil fuel power generation is better, Modahl points out.  

- A challenging process

The study is based on data from reliable, peer-reviewed, and relevant literature, and the data has been recalculated to a common functional unit to be able to make a fair comparison. 

- It has been challenging to process the information to make the results comparable, and we have focused on only reviewing literature that is based on recognised methodology for CCU systems, Modahl says.

The content of the available literature allowed the researchers to present the findings for climate impact with numerical values. The findings for resource use and other environmental indicators had to be described more qualitatively.

Debated topic

The researchers are aware that their study will be debated and that there are stakeholders who might have a different view when it comes to utilising the economic potential of captured CO2 to produce fuels and chemicals. 

Modahl emphasises that NORSUS's task is to present an environmental factual basis and finds that she and her colleague Raadal have done just that. 

- Our findings are solid. The authorities can use our study in their prioritisation and future energy policy, and it can be utilised as a basis for further research. We hope that the results will contribute to making choices and prioritisations that reduce climate change burdens, says Ingunn Saur Modahl. 

The report also forms the basis for other research activities in the "CCUS Verdiskapingspotensialet – næringsutvikling og innovasjon " project. Already this spring, mineralisation of captured CO2 will be studied to map the potential and actual energy requirements.

The CCUS project is partly funded by the former Viken County Council.