Can carbon capture and utilisation contribute towards the Paris Agreement's goals?

As part of ongoing collaboration with the IEA Greenhouse Gas R&D Programme and Japanese stakeholders, our latest report considers the extent to which carbon capture and utilisation (CCU) technologies potentially drive emission reductions at a national level, and how these might collectively contribute towards countries' climate mitigation goals under the Paris Agreement.

The analysis was undertaken using an in-house model - the GHG Emissions Model for Carbon Capture and Utilisation ("GEMCCU") - that incorporates the lifecycle GHG emissions effects of different CCU technologies and allocates them to IPCC Reporting Categories used in compiling economy-wide national GHG inventories. Using the GEMCCU architecture, we assessed the potential of four different CCU technologies to contribute towards climate mitigation goals set out in Japan's nationally determined contribution (NDC) and long-term low emission development strategy (LT-LEDS). The analysis undertaken incorporates ambitions described in Japan’s national roadmap for CCU.

Example output from the GEMCCU model

Results from GEMCCU suggest that utilising 5 to 25 MtCO2 in CCU applications could potentially drive net emissions changes of -5.4 and -17 MtCO2 in 2030 and 2050 respectively under base case assumptions. We also found that these effects could be increased to, respectively, -6.4 and -28 MtCO2 if process efficiency improvements can be acheived. On the other hand, overall emissions effects fall to -0.3 and -6.8 MtCO2 respectively if grid electricity is assumed to be the source of power (rather than 100% zero carbon electricity). Up to 22GW of new, zero-carbon, electricity generation capacity could be needed to achieve the optimum emissions effect.

Some caution is needed in interpreting the results. The MRV treatment of algal-derived biofuels has particularly significant impacts on the modelled outcomes. Where emissions from these fuels are assumed to be zero-rated, significant emission reductions can be achieved. However, in situations where the algae exclusively consume fossil CO2 in their growth cycle, it is a matter of debate whether emissions from these products should be zero-rated since they are not absorbing atmospheric CO2. In zero-rating these emissions, something of a paradox is created: electro-conversion of fossil CO2 to fuel (e.g. MeOH) requires the CO2 product emissions to be counted, whereas biological conversion by algae does not. Further consideration of this matter is needed to clarify their treatment in national GHG inventory compilation.

The full report containing much more information will soon be available from the IEA Greenhouse Gas R&D Programme.