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New IEAGHG Technical Review: Carbon Capture and Utilisation as a Contribution to National Climate Change Mitigation Goals: Japan Case Study

This report builds upon previous IEAGHG studies on the topic of carbon capture and utilisation (CCU) (IEAGHG 2018a, IEAGHG 2018b, IEAGHG 2018c, IEAGHG 2019), all having been carried out by Carbon Counts. First, an update on recent CCU policy developments is set out. Second, previous research and analysis is assembled into a model – the Greenhouse Gas Emissions Model for CCU (GEMCCU) – to examine the emission reduction potential of CCU on an integrated basis. GEMCCU is used to assess the potential of a portfolio of CCU technologies to contribute towards Japan's climate change mitigation goals in 2030 and 2050.

The research finds that interest in CCU around the world continues apace, building upon the momentum identified in previous studies. Developments include:

  • OECD countries are increasingly highlighting the important role that CCU could play within their national decarbonisation strategies.
  • The United States, European Union and Japan could provide RD&D funding for CCU in excess of US$700 million over the next 10 years.
  • Evaluations of the climate change mitigation potential of CCU in the literature suggest that CO2 utilisation rates in the order of 100 to 1,100 MtCO2 by 2050 could be achieved under scenarios of comprehensive and sustained climate action.

Using two scenarios – 'scenario 2030' and 'scenario 2050' (5 and 25 MtCO2 utilised, respectively) – various combinations of CO2 sources and end use pathways, and a range of key sensitivities (accounting mode, source of electricity, various process efficiency improvements), an assessment is made of the potential of CCU to contribute towards Japan's climate mitigation goals.

Analysis suggests that using 5 to 25 MtCO2 in CCU applications could potentially drive net CO2 emissions changes of -5.4 to -17 MtCO2 under base case assumptions. The emissions reduction effect increases to, respectively, -6.4 to -28 MtCO2 with improved efficiency but decreases to -0.3 to -6.8 MtCO2 if grid electricity is assumed as the source of power (rather than 100% zero carbon electricity). The base case contribution represents between 2 and 6.4% of Japan's estimated mitigation efforts to 2030 and 2050 respectively and could reach over 10% in 2050 if improved efficiency can be achieved.

Achieving best-case results would require, by 2050, the addition of up to 22 GW of new zero carbon electricity generating capacity dedicated to CCU. Equally, analysis suggests that electricity grid emissions factors lower than 460-500 kgCO2e/MWh could be sufficient to deliver a net emissions reduction effect in the scenario 2030 base case. This decreases to 175-275 kgCO2e/MWh in scenario 2050, where higher utilisation rates and a wider portfolio of CCU technologies is employed.

Analysis using GEMCCU indicates that the most appropriate means to account for the climate mitigation effect of CCU technologies is to count the emissions reduction from capturing CO2 at source ('upstream' accounting). This requires all downstream emissions of the captured CO2 to be treated in the same way as fossil CO2 emissions. Approaches that instead count the climate mitigation 'downstream' miss emissions reduction effects when the CO2 is integrated into products with long-term storage (e.g. mineralisation technologies).

Zero-rating emissions from algae-derived fuels, assumed on the basis of them being biofuels despite being fed exclusively on fossil CO2 feedstock, presents a potential emissions accounting "loophole" that could mean the emission reduction effects of CCU are overstated. Further clarification of the measurement and reporting methods for algal fuels is therefore recommended. Under a worst-case scenario (grid electricity supply and accounting of emissions from algal fuel use as fossil CO2 emissions) the net emissions change from deploying the modelled portfolio of CCU technologies would instead be +2.7 to +3.2 MtCO2 for scenario 2030 and scenario 2050 respectively.

Technical and market constraints on polycarbonate and mineralisation pathways mean that as little as 300 ktCO2 utilised would be sufficient to saturate Japan's current markets for these products. Long-term CCU strategies will therefore inevitably involve electro-intensive pathways using hydrogen for electro-fuel production. It is also notable that in scenario 2050 the domestic production of CO2-derived methanol could "onshore" around 6 MtCO2 onto Japan's national GHG emissions inventory.

For a copy of this report, please email This email address is being protected from spambots. You need JavaScript enabled to view it. quoting reference number 2021-TR04.

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