Last month Prime minister Suga pledged to reduce Japan carbon emissions by 46% (from 2013 levels) by 2030. If the objective in itself is good news for the climate, no analysis, plan and policies have been disclosed by the government. Japan previous target was 26%, and this increase will require major additional cuts in the next 9 years. Mr. Suga did not specify if this target was compatible with his concept of “green growth” or if the potential economic impact would require sacrifices from the Japanese public.
The new carbon emissions reduction target means that Japan will have to reduce its emissions by an average of 38 MtCO2 every year, or the equivalent of 3.7% of 2018 levels.
However, two more constraints need to be considered. The first one is the pledge to carbon neutrality by 2050. To reach it Japan would need to reduce its emissions by 33 MtCO2 every year from 2031. This however would overshoot the 2 degrees C global target.
According to the IPCC 5th report and Worldwide emissions since 2011 (climatewatch data, CAIT incl. LUCF), the world can still release a total of ~625 GtCO2-eq to stay in the >66% probability to not go above the target 2C. In 2018, Japan emitted ~2.36% of global CO2-eq. Ideally Japan would no emit more than 14,800 MtCO2-eq in total after 2018. To stay within this target, it should either increase the 2030 46% goal or aim for a more aggressive annual reduction after 2030, ideally a reduction of more than 60MtCO2/year the first few years.
To reach the 46% reduction target for 2030, Japan will have to reduce its emissions by an average of 38 MtCO2 every year, or the equivalent of 3.7% of 2018 levels.
To put this number in perspective, the effect of COVID 19 on the global carbon emissions for 2020 is estimated at ~7%, most of it coming from the reduction in transportation (Stanford earth). Japan would need to add an extra (cumulative) COVID every 2 years to meet its target. In other words, a drastic change in consumption patterns and the way we live our life would be required. This might be necessary to some extend in the long term, or it might be imposed by the consequences of missing our GHG reduction targets.
In the short term however their might be better options to reach the 46% goal. METI could focus on the biggest GHG emitters, coal plants (~30% of current total emissions). There are ~150 coal plants in Japan, for a total of 48GW, producing 330TWh in 2019 (METI) and therefore emitting ~ 330 MtCO2/year. Japan would need to replace the equivalent of ~5GW of coal plant generation by carbon neutral generation capacity every year for the next 10 years. It would still be ~50 MtCO2/year short to reach its target but this would be a major step.
This would obviously not be an easy solution, as coal plants are dispatchable and account for 31% of Japan energy mix. The easiest path would be to use nuclear capacity to phase-out coal plants in the next decade. If Japan had 48GW of nuclear capacity in 2011, it now has only 33 reactors classified as operable for a total of 31.6 GW (World nuclear association); not enough to fully replace coal but this could still cover 190 TWh/year, ~60% of the phased-out capacity (assuming a capacity factor of 85% for nuclear and the ~40 TWh/year current production). The remaining 140 TWh/year could be provided by Solar, Wind, Biomass and Geothermal. This would require to more than double their contribution to the energy mix to 27%, with total renewable share going up to 33%.
Given the unofficial targets rumored from METI these past months this could be an option. Grid integration would of course be an issue as pointed out by the latest OCCTO draft master plan for the development of Japan interconnections.
In a future insight we will compare the different options to decarbonize the energy mix as, coupled with the electrification of other sectors, it is likely to be at the center of the Japanese carbon reduction strategy.