11

Japan’s Quantitative Emission Scenario of GHG Net Zero and
its Implications for Asian Countries
Go HIBINO1*, Shuichi ASHINA1, Diego SILVA HERRAN1, Toshihiko MASUI1,
Yuko MOTOKI2, Tomoki HIRAYAMA2 and Takaharu OTA2
1

Social Systems Division, National Institute for Environmental Studies
16-2 Onogawa, Tsukuba-shi, Ibaraki 305-8506, Japan
2
Sustanability Consulting Division 1, Mizuho Research & Technologies, Ltd.
2-3 Kanda-Nishikicho, Chiyoda-ku, Tokyo 101-8443, Japan*E-mail: hibino.go@nies.go.jp

Abstract
Japan enacted legislation in 2021 incorporating the aim of achieving net zero greenhouse gas (GHG)
emissions by 2050 based on temperature targets set in the Paris Agreement. Our research attempted toquantitatively express the combination of technologies, energy supply and demand, and structure of GHG
emissions required to achieve net zero GHG emissions by 2050. The combination of measures necessary toachieve this goal was estimated by using a computable general equilibrium model, a technology selection
model and an optimal generation planning model while considering factors including the consistency of the
future economy and energy demand, feasible technology deployment speed and the maintenance of regional
and temporal balances for electricity demand and supply. The results show that major changes in the energy
system will be necessary, including shifting from fossil fuel to electricity, expanding the use of hydrogen andhydrogen-based fuels, and expanding the use of renewable energy. Also, negative emission measures will be
required to address residual emissions. In addition, reducing energy demand through social transformation wasshown to reduce dependence on measures the efficacy of which is highly uncertain and thereby increase thepossibility of achieving net zero GHG emissions. These findings are also applicable to building a decarbonizedsociety in Asian countries, while taking into account each country’s stage of development and taking advantage
of climatic and regional characteristics.
Key words: computable general equilibrium model, decarbonized society, net zero GHG emissions,
optimal generation planning model, renewable energy, technology selection model

1. Introduction
At the start of the 2010s, Japan’s greenhouse gas(GHG) emissions rose due to the impact of the nuclear
power plant accident caused by the Great East Japan
Earthquake. However, since peaking in FY2013 at
1.41Gt-CO2eq, emissions have decreased for six
consecutive years, with emissions in FY2020(1.15Gt-CO2eq) being 18.4% less than emissions in 2013
(Fig. 1). CO2 accounted for more than 90% of GHG
emissions in FY2020 (84% energy-related CO2, 7%
non-energy related CO2), while methane and N2O eachaccounted for 2%, and four other gases including CFC
alternatives accounted for 5% (NIES, 2022).
Japan’s GHG emission reduction target as pledgedin the INDC (Intended Nationally Determined
Contributions) submitted to the United Nations
Global Environmental Research
26/2022 011−021
printed in Japan

Fig. 1

Japan’s GHG emissions and reduction targets.
©2022 AIRIES12

G. HIBINO et al.

Framework Convention on Climate Change (UNFCCC)
Secretariat in 2015 and the NDC (Nationally Determined
Contributions) submitted in March 2020 was a 26%
reduction in FY2030 relative to emissions in FY2013. In
addition, the target for 2050 in the long-term strategy
submitted to the UNFCCC Secretariat in June 2019 was
an 80% reduction. In October 2020, then Prime Minister
Suga declared that Japan would aim to achieve carbon
neutrality by 2050. This was followed by an amendmentof the Act on Promotion of Global WarmingCountermeasures to incorporate net zero GHG emissions
by 2050 as a target. In addition, after a meeting of the
Global Warming Prevention Headquarters, Prime Minister
Suga stated that Japan would seek a 46% reduction inemissions by 2030 and would continue to aim to cut
emissions by 50%. A subsequent internal review by thegovernment led to the formulation of a plan consistent
with these targets and approval by the Cabinet of a revised
Plan for Global Warming Countermeasures on October 22,
2021. The revised NDC incorporating the targets andlong-term strategy was resubmitted to the UNFCC
Secretariat. Japan had finally made a start towardachieving net zero GHG emissions.
However, the process of compiling the necessary
combination of substantive countermeasures and policies
to achieve the new ambitious target of 46% reduction by
2030 has been extremely difficult. The government’s planfor 2050 does not set forth a list of necessary substantive
countermeasures.
Our analysis used the three models described in thenext section to estimate the combination of measuresrequired to achieve net zero GHG emissions in 2050 withthe goal of providing information that will contribute torealizing a decarbonized society in Japan.
Currently, 133 countries around the world havedeclared net zero emission goals (Net Zero Tracker, as ofDecember 26, 2022), and in Asia, major countries such as
China, India, Indonesia, South Korea, Malaysia, Thailand
and Vietnam have all declared net zero emission goals. In
this context, we also describe the implications of
the findings from our analysis of Japan for the
decarbonization of societies in Asian countries.
The analysis of Japan in this paper is based on thework presented in Hibino et al. (2022, in Japanese), andadds suggestions for a decarbonized society in Asia
derived from the Japanese analysis.

2. Methods
2.1 Analytical Models
The three models shown in Fig. 2 were used in thisanalysis.
A recursive dynamic computable general equilibrium
model for Japan (AIM/CGE) was used to estimate thefuture volume of services. AIM/CGE quantitatively
projects future economic activity based on theassumptions for future economic outlooks by using thepricing mechanism to ensure consistency in theinterrelationships of the economy as a whole. The
economic activity in each sector was estimated based on
the production value of goods and services estimated by
the model. The results were used to estimate future

Fossilfuel

Fig. 2Models used in the analysis.

Japan’s Net Zero Scenario and its Implications for Asia

service volumes such as material production, commercial
floor space, and freight transportation for the final energy
consumption sector. Details of AIM/CGE are described in
Masui (2005).
Next, the technology selection model AIM/Enduse(v1.0) was used to estimate future energy demand. The
AIM/Enduse model selects the energy equipment thatminimizes costs for each year while satisfying therequirements for the exogenously input service volumes.
Energy consumption is estimated by summing thetechnology for each service type by sector for Japan until
2050. Since the amount of technology replacement iscalculated taking into account the technology’s vintage,
the rate of new technology introduction reflects the life
span of the technology. Details of AIM/Enduse (V1.0) aredescribed in Kainuma et al. (2003).
The AIM/Multiregional Optimal Generation Planning
Model (AIM/MOGPM) was applied to the power sector
to estimate a generation mix. This model can analyze thehourly electricity demand-supply balance including theinter-regional power interchange and storage input-output
each of the 10 regions set based on the jurisdiction area ofthe electric power companies (EPCOs) such as Tokyo
Electric Power Company (TEPCO) under the cost
minimization condition. The model estimates a generation
mix and primary energy consumption required forgeneration considering capital costs, operation andmaintenance costs and fuel costs as well as the cost ofelectricity storage, cost of expansion of interconnection
transmission lines, and curtailment of renewable energy
output (amount of disconnection). The electricity demandused in the model is set based on results from thetechnology selection model. Details of AIM/MOGPM aredescribed in Gao and Ashina (2022).
The total energy supply and demand for Japan andthe corresponding CO2 emissions were calculated byusing the energy consumption for power generation
estimated by AIM/MOGPM and the energy consumption
for uses other than power generation estimated by AIM/
Enduse. For GHG emissions other than energy-related
CO2, current emission rates and estimated reduction rates
due to countermeasures were calculated for each gas andemission source, and the quantity of reductions andemissions were calculated by multiplying the two.
2.2 Analytical Framework(1) Assumptions regarding Future Society and theEconomyFor future GDP assumptions, a GDP growth rate up
to 2030 of 1.7%/year is taken from the growth realizationcase in Cabinet Office (2021). GDP growth of 0.5%/year
after 2030 is taken from the SSP2 scenario for the
projected Japanese GDP rate from the IIASA SSP (Shared
Socioeconomic Pathways) database (IIASA, 2018).
Projected populations are taken from the mediumfertility/medium-mortality case of the National Institute of

13

Population and Social Security Research (2017).
Future production volumes for materials andmachinery products in the industrial sector were
calculated from the production values by industry
estimated by AIM/CGE based on the above assumptions
for GDP. Commercial floorspace was calculated based on
the purpose of buildings; for example, the floorspace for
office buildings was estimated based on the number of
employees; that for commercial facilities, on the
production volume of commercial and personal services;and that for hospitals and schools, on the population
composition. Passenger transportation was calculated
from the future total population while freighttransportation was calculated based on the current
transportation volume for goods and future production
values. The data for main activities are shown in Table 1.
(2) Reduction Measures
There are four main pillars for reducing energyrelated CO2 emissions to realize a decarbonized society:1) reduction of demand for energy services, 2)
improvement of energy efficiency, 3) promotion ofelectrification, and 4) decarbonization of energy
production. For each of these pillars, a detailed list of
countermeasure technologies was developed for eachsector (Table 2). Measures to address GHG emissions
other than energy-related CO2 are listed in Table 3.
The model endogenously selects economical
countermeasure technologies by considering fixed andvariable costs including energy costs. Future cost
reductions are anticipated for some technologies.
Forecasts by IRENA (2019) were used for solar
photovoltaic and wind power generation while forecasts
by the Council for a Strategy for Hydrogen and Fuel Cells(2019) were used for hydrogen prices. For energy prices,
the carbon price is assumed to be a maximum of ¥40,000/t
CO2 up to 2050. Furthermore, it is assumed that a portionof tax revenues will be used to subsidize electric vehicles,
fuel cell vehicles and electric heat pump water heaters.
(3) Constraints on Energy Supply
It was assumed that about 30% of the hydrogen andsynthetic fuels supply will be dependent on imports and100% of ammonia will be imported.
Table 1 Major future activities and conditions.
FY2018 FY2050
2020–2030 1.7%
GDP growth rate2031–2050 0.5%
Population (000)126,440 101,923
Number of households (000)53,88947,241
Crude steel production (million tons/year)
102.9
85.7
Cement production (million tons /year)
60.2
60.4
Ethylene production (million tons /year)
6.2
5.4
Paper/paperboard production
26.0
23.4
(million tons /year)
Machinery production (2015 = 100)
100
141
Commercial floorspace (million m2)
1,903
1,671
Passenger transportation (billion person-km)
1,459
1,179
Freight transportation (billion t-km)
411
419

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Table 2

G. HIBINO et al.
Energy-related CO2 emission reduction measures.

Countermeasure Pillars
1) Reduction of demand for energy services

Context of Measures
Industry*: Extend product service life, resource-saving design, shared use, circular use, useof wood for structures
Commercial/Residential: Increase building insulation, energy management
Transportation*: Reduce transportation of persons and goods through digitalization,
improve transportation efficiency
2) Improved energy efficiency
All Sectors: Improve efficiency of energy consuming equipment
3) Promotion of electrification
Industry: Use heat pumps to supply low and medium heat, increase use of electric furnaces
Commercial/Residential： Increase use of heat pumps for heating and hot water supply
Transportation: Electric and fuel cell vehicles
4) Decarbonization of energy
Generation: Renewable energy, CCUS
Industry: Hydrogen direct reduced iron, CCUS
All sectors: Increase use of hydrogen and synthetic fuels* These are considered in the “technology + social transformation” scenario discussed later.
Table 3

Reduction measures for GHG emissions other than energy-related CO2.

Countermeasure Pillars
Industrial Processes
Agriculture related
Waste management
Four Gases incl. alternative CFC

Main Measures
Reduction of clinker ratio, CCUS
Agricultural soil measures, Control measures for rice paddy and livestock origin CH4, N2O
Promotion of 3R measures, Reduced use of petroleum derived products
Development and deployment of low GWP gases, prevention of leakage, capture and treatment

The upper limit for the deployment of renewableenergy was set by referring to the Ministry of theEnvironment’s Renewable Energy Potential System(REPOS) (2020). For example, the upper limits for solar
photovoltaic, onshore wind power and offshore wind
power were set at 350 GW, 118 GW and 178 GW,
respectively.
(4) Scenarios
The Intergovernmental Panel on Climate Change(IPCC) is analyzing emission pathways that would limit
the increase in average global temperature to 1.5°C (IPCC,
2018, 2022). We have analyzed emission pathways basedon low energy demand scenarios assuming that
decarbonization of the energy system will be induced bydemand-side transformations of society, business andtechnology. Compared to other scenarios, there will belower future dependence on negative emissions, and thetotal amount of renewable energy deployed will besmaller.
To examine the effects of social transformation in
Japan, we analyzed future emissions and other factors
for two scenarios to achieve net zero emissions: a“technology” scenario based on the deployment
of decarbonization technologies including energy
conservation, renewable energy and electrification and a“technology + social transformation” scenario thatassumes digitalization and a move towards circular
economy in addition to the deployment of decarbonization
technologies.
The low energy demand (LED) scenario (Grubler etal., 2018) adopted by the IPCC (2018) was referenced forthe “technology + social transformation” scenario. For theindustrial sector, it is assumed that the volume of goods
produced will be reduced by 15% in 2050 compared to

the “technology” scenario due to more efficient use ofmaterials including longer product service life,
resource-saving design and sharing. For the transportation
sectors, it is assumed that the volume of passenger andfreight transportation will be reduced by 20% in 2050
compared to the “technology” scenario due to reduction indemand and increased efficiency from digitalization anddematerialization. No differences between the two
scenarios were assumed for the commercial andresidential sectors.

3. Simulation Results
3.1 Final Energy Consumption by Sector
Energy consumption in the final energy consumption
sectors was estimated by using AIM/Enduse. The results
are shown below.
(1) Industrial Sector
Figure 3 shows the final energy consumption for theindustrial sector in 2018 and 2050. Compared to 2018,
final energy consumption in 2050 is 22% lower for the“technology” scenario and 33% lower for the “technology+ social transformation” scenario. The effect of socialtransformation, as evaluated by comparing the“technology” and “technology + social transformation”
scenarios for 2050, is estimated to be a 15% reduction.
Also, the effect of deploying countermeasure technology
was calculated by comparing energy consumption for2050 in both scenarios with a “fixed technology” scenario
while holding activity constant; the reduction is estimatedto be 21% for both scenarios. Fossil fuel consumption isabout 90% lower in 2050 than in 2018. Although coal isstill consumed in 2050, it is only consumed by the steel
and cement industries and both industries have installedJapan’s Net Zero Scenario and its Implications for Asia

CO2 capture technologies for coal consumption. In
contrast, the shares of electricity, hydrogen and synthetic
fuels increase. For both scenarios from 2018 to 2050, theshare of electricity increases from 20% to 34%, hydrogenfrom 0% to 23%, and synthetic fuels from 0% to 18%(percentages of consumption as energy excluding
non-energy use).
(2) Commercial and Residential Sectors
Figure 4 shows the final energy consumption in 2018and 2050 for the commercial and residential sectors. The
commercial and residential sectors generally show similar
trends. As there are no differences in the assumptions
between the “technology” and “technology + socialtransformation” scenarios for the two sectors, only one
energy consumption is shown for each sector in 2050.
Final energy consumption in 2050 is 51% lower forthe commercial sector and 53% lower for the residential
sector compared to 2018. Also, the effect of deploying

countermeasure technology, as evaluated by comparing
energy consumption of both scenarios with a scenario
using “fixed technology” while holding activity constant,is estimated to be 55% for the commercial sector and 45%
for the residential sector. By energy type, the share offossil fuel decreases while the share of electricity
increases. Between 2018 and 2050, electricity as a shareof final energy consumption increases from 54% to 93%
in the commercial sector and from 51% to 74% in theresidential sector. Regarding energy consumption by
application, large decreases in energy consumption areseen in both sectors for air conditioning/heating and hot
water supply compared to 2018, with a 76% reduction forthe commercial sector and a 61% reduction for the
residential sector for air conditioning/heating and an 81%
reduction for the commercial sector and a 73% reduction
for the residential sector for hot water supply.

<By source><By source><By industrial subsector>
Paper and pulp

<By industrial subsector>

Iron and steel

Fig. 3

Final energy consumption in the industrial sector (Mtoe).
<By source><By use>Fig. 415

Final energy consumption in the commercial and residential sectors (left: commercial, right: residential, Mtoe).

16

G. HIBINO et al.

(3) Transportation Sector
Figure 5 shows the final energy consumption for thetransportation sector for 2018 and 2050. Compared to2018, final energy consumption in 2050 is 74% lower for
the “technology” scenario and 79% lower for the“technology + social transformation” scenario. The effectof social transformation, as evaluated by comparing the“technology” and “technology + social transformation”
scenarios, is estimated to be a 20% reduction. Also, theeffect of deploying countermeasure technology, as
evaluated by comparing both scenarios to a scenario using“fixed technology” while holding activity constant, isestimated to be a 72% reduction for both scenarios.
Regarding energy consumption by application, passenger
vehicles and freight vehicles currently account for a highproportion of energy consumption in the transportation
sector and significant reductions in energy consumption
by both vehicle types (passenger vehicles: 88%–91%
reduction, freight vehicles: 66%–72% reduction)
contribute greatly to the overall reduction in energy
consumption.
Regarding the energy mix, the proportion of fossil
fuels decreases and the proportions of electricity,hydrogen and synthetic fuels increase. In 2018, electricity
was used only for railroads and did not exceed 2% of theenergy used for transportation while hydrogen andsynthetic fuels were not consumed. In 2050, theproportion of electricity increases to 41% while hydrogen
increases to 21%–22% and synthetic fuel to 24%–26%.
By 2050, almost 100% of passenger vehicles will beelectric vehicles. In contrast, as the use of batteries forstoring energy for freight vehicles will result in theextremely high weight of batteries, a portion of freightvehicle will be non-electric vehicles including hydrogenfuel cell vehicles (accounting for 35% of energy
consumption) and internal combustion locomotives
powered by synthetic fuels (accounting for 32% of energy
consumption).

(4) Final Energy Consumption Sector
Figure 6 shows the final energy consumption for2018 and 2050 for the final energy consumption sector,
which is the sum of the industrial, commercial, residential
and transportation sectors. The total final energy
consumption for 2050 compared to 2018 is reduced by
42% for the “technology” scenario and by 49% for the“technology + social transformation” scenario. The effectof social transformation, as evaluated by comparing
energy consumption in 2050 for the two scenarios, isestimated to be a 12% reduction. Also, the effect of
deploying countermeasure technologies, as evaluated bycomparing both scenarios with a “fixed technology”
scenario while holding activity constant, is estimated to bea 39% reduction for both scenarios. Regarding the energy
mix, the proportion of fossil fuels decreases while theproportion of electricity, hydrogen and hydrogen-based
fuels increases. The proportion of electricity increases
from 26% in 2018 to 49%–51% in 2050 while theproportion of hydrogen and hydrogen-based fuels
increases from no consumption in 2018 to 31%–33% in
2050.
(5) Demand for Hydrogen and Hydrogen-based Fuels
Figure 7 shows the demand for hydrogen andhydrogen-based fuels in 2050. The demand for hydrogenis 52–61 million tons oil equivalent (Mtoe). Hydrogen isnecessary for producing synthetic fuels, and demand forsynthetic fuel production accounts for more than 50% of
total hydrogen demand. Demand for synthetic fuel is 34–
40 Mtoe, with industrial use (including non-energy use)accounting for about 80% of demand. Demand forammonia in 2050 will be 17 Mtoe, mostly for electricity
generation.
In Japan, synthetic fuels will be produced using CO2
captured from electricity generation or the industrial
sector. Excluding CO2 captured from biomass power
generation used for synthetic fuel production,
consumption of synthetic fuels produced from CO2 from

<By source><By mode>

Fig. 5

Final energy consumption in the transportation
sector (Mtoe).

Fig. 6

Final energy consumption (Mtoe).

Japan’s Net Zero Scenario and its Implications for Asia

fossil fuels and limestone is included in CO2 emissions.
(6) Demand for Electricity
Figure 8 shows the demand for electricity for 2018and 2050. Electricity demand in 2050 will increaseby 30%–46% compared to 2018. While the demand
for final consumption sectors (industrial + commercial +residential + transportation) will decrease, the demand for
production of hydrogen and hydrogen-based fuels(primarily for electrolytic hydrogen production) will
increase.
3.2 Electricity Generation
The electricity demand estimated by AIM/Enduse
was downscaled to 8,760 hours (24 hours x 365 days) by
the EPCOs’ jurisdiction areas (10 regions). In the model,
electricity demands for hydrogen production have been
allocated as surplus electricity while keeping the capacity
factor of hydrogen production facilities more than 60%.
The electricity demand for hydrogen and synthetic fuel17

production was assumed not to be constrained by region
or time.
Figure 9 shows electricity generation in 2018 and
2050, while the mix of renewable energy power
generation is shown in Fig. 10. The share of decarbonized
power sources in electricity generation increases from
25% in 2018 to 100% in 2050. The proportion ofrenewable power generation increases from 17% in 2018
to 73%–76% in 2050; solar photovoltaic generates 403–
405 TWh in 2050, while onshore wind generates 133–226
TWh, and offshore wind generates 205–276 TWh.
3.3 Domestic Primary Energy Supply
Currently, fossil fuels account for more than 80% ofJapan’s primary energy supply. Renewable energy sources
will account for about 70% of primary energy in 2050.
This represents an improvement in energy self-sufficiency
from 15% in 2018 to more than 70% in 2050.

Industrial autoproducer

Fig. 9Fig. 7 Demand for hydrogen and hydrogen-based fuels(2050, Mtoe).

Power generation mix (TWh).

PV (others)

Industrial autoproducer

transformation

Fig. 8

Electric power demand (TWh).

Fig. 10

Renewable energy power generation mix (TWh).

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G. HIBINO et al.

3.4 CO2 Capture and Use
CO2 capture in 2050 will be 147–157 million tons of
CO2 (MtCO2). CO2 will be captured from the steel,cement and petrochemical industries in the industrial
sector and natural gas-fired and biomass-fired thermal
power plants in the power generation sector. Of thecaptured CO2, 49–57 MtCO2 will be used to produce
synthetic fuels, and the remaining 97–99 MtCO2 will be
stored underground.
3.5 GHG Emissions
Figure 11 shows GHG emissions for 2018 and 2050.
Emissions from the consumption of synthetic fuelsaccount for a considerable proportion of energy-related
CO2 emissions in 2050. Some GHG emissions will be
unavoidable in 2050 even if decarbonization measures arepromoted. Our analysis estimates total GHG emissions of
102–114 MtCO2, broken down as follows: 55–65 MtCO2
from energy-related CO2; 19–22 MtCO2 from nonenergy-related CO2; and 27–30 MtCO2eq from methane,
N2O and the four gases including CFC alternatives. Forest
sequestration, bioenergy with carbon dioxide capture andstorage (BECCS), and other negative emission
technologies will be required to offset these emissions.

Fig. 11

GHG emissions (MtCO2eq).

3.6 Additional Investment AmountFigure 12 shows the annual average additional
investment from 2041 to 2050. The amount of investment
required for insulation of houses and other buildings andrenewable energy accounts for a considerable proportionof the additional investment.

4. Towards Realization of a DecarbonizedSociety in Japan
4.1 Conversion of the Energy System
As energy-related CO2 emissions accounted for 84%
of Japan’s GHG emissions in FY2020 (Ministry of theEnvironment, 2022), decarbonization of the energy
system is the most critical issue for achieving net zero
GHG emissions. Based on our analysis, the key points forthe energy system in 2050 are as follows:(1) Reduction of energy demand by 40% to 50% throughsocial transformation and deployment of technologies
for improving energy efficiency.
(2) Regarding reduced final energy demand, promotionof electrification so that the proportion of electricity
in final consumption is 50% (26% in 2018).
(3) As the electrification of all energy applications will
be difficult, use of hydrogen and hydrogen-based
fuels for industrial applications for high-temperature
heat, large-scale transport, and other fields where
electrification is difficult.
(4) However, as electricity will be required to producehydrogen and hydrogen-based fuels, combined withthe electrification of the final consumption sector, theFig. 12Additional investments (annual average: 2041–2050,
trillion yen).

amount of electricity generated is estimated toincrease by more than 30% from current levels.
Power generation will be provided by 100%
decarbonized power sources. This will require thesupply of electricity from renewable energy sources
to increase to more than five times the current levelof 200 billion kWh.
(5) In addition, 150 million tons of CO2 will be captured
from the remaining consumption of fossil fuels forelectricity generation and industrial applications.
About one-third of the recovered CO2 will be used to
produce synthetic fuels while the remaining 100
million tons of CO2 will need to be stored
underground.
(6) Annual investment of about 10 trillion yen will be
required for the decarbonization of the energy
system.

Japan’s Net Zero Scenario and its Implications for Asia

19

Currently, fossil fuels account for 70% of final
energy consumption, and fossil fuel-fired thermal power
generation accounts for 70% of electricity generation. The
fossil-fuel-based energy system will need to betransformed into the renewable-energy-based energy
system described above.

scenario including social transformation reduces thedependence on currently undeployed decarbonization
technologies, including the amount of negative emission
technology required (55→43 MtCO2); reduces imports ofhydrogen and hydrogen-based fuels (47→42 Mtoe); andreduces wind power deployment (276→205 TWh).

4.2 Deployment of Negative Emission Measures
It is extremely difficult to completely control GHG
emissions and reduce emissions to net zero without
offsetting emissions with sequestration. Our estimatesshow that in 2050 the use of synthetic fuels, GHG
emissions including CO2 emissions from industrial
processes and waste incineration, and emissions of CH4
and N2O from the agriculture and livestock industries will
result in GHG emissions of about 100 MtCO2, which isequivalent to about 10% of GHG emissions in 2018. The
only negative emissions measure aimed at capturing CO2
from the atmosphere currently being implemented is CO2
sequestration by forests; in 2020, 57 MtCO2 were
estimated to be sequestered by forests in Japan (NIES,2022). However, as Japanese forest plantations age, theamount sequestered by forests will tend to decrease(MAFF, 2021) and significant increases in sequestration
cannot be expected. Thus, other negative emission
measures including BECCS, direct air capture (DAC),
biochar, and blue carbon management will be required(IPCC, 2022). However, these measures are in the R&D
stage and have not reached the stage of widespread
deployment. To increase the possibility of Japan achieving
net zero emissions, promotion of R&D and acceleration of
deployment for these technologies will be necessary.

5. Implications for Achieving a DecarbonizedAsia

4.3 Social Transformation Toward a DecarbonizedSocietyIn this analysis, we attempted to calculate the effectof social transformation on the reduction of GHG
emissions by using two scenarios. The effects ofdematerialization on goods production (15% reduction ingoods production) and the effects of digitalization anddematerialization on demand for transportation (20%reduction in demand for transportation) were consideredin the “technology + social transformation” scenario. The“technology + social transformation” scenario led to a
12% reduction in final energy consumption compared to
the “technology” scenario.
Achieving social transformation increases thelikelihood of achieving a decarbonized society. Achieving
net zero emissions will also depend on the deployment ofdecarbonization technologies that are currently not widelyused. However, there is a high degree of uncertainty
regarding various social, economic and technologicalaspects associated with the deployment of thesetechnologies. Thus, reduction of energy demand throughsocial transformation will reduce the dependence on
highly uncertain technologies and increase the possibilityof achieving a decarbonized society. In this analysis, the

5.1 Renewable Energy Power Generation
Our analysis of Japan suggests that a significant
increase in renewable energy generation will be necessary
to achieve carbon neutrality. The transition from thermal
power generation to solar and wind power generation,
which are highly variable, will be a challenge. Currently,
the share of thermal power generation in the power
generation mix in Asian countries is about 70% in all
major countries and regions (Japan 73%, China 67%,
India 76%, ASEAN 76% in 2020, (IEA, 2022). On theother hand, there are differences in the amount ofelectricity generated per capita. Japan's per capita
generated electricity has remained at 8–9 MWh/year/
person for the past 20 years. China's was around 1 MWh/year/person in 2000 and reached 5.5 MWh/year/person in
2020. India and ASEAN are 1.1 and 1.7 MWh/year/
person, respectively, in 2020 (IEA, 2022). A large numberof new power plants are expected to be built in India and
ASEAN. Considering that thermal power generation has alifetime of about 40 years, the newly built plants willremain in 2050. Therefore, those plants that are not readyfor CCUS or conversion to hydrogen-based fuels will
become stranded assets with respect to CN realization.
Future new construction should be shifted mainly torenewable energy generation. To this end, it will beessential to strengthen the power grid in parallel.
5.2 Hydrogen-based fuelIn areas where electrification is difficult, such as
high-temperature thermal applications in the industrial
sector and freight vehicles, ships and aviation in thetransportation sector, Japan’s analysis suggests that theuse of hydrogen-based fuels is inevitable fordecarbonization. This is true for all countries, where theseapplications exist, and the supply of hydrogen-based fuels
is a common challenge. The production of carbon-freehydrogen fuels will either be based on fossil fuels, withsequestration and storage of carbon emissions, or byelectrolysis using renewable energy generation. In orderfor synthetic fuels to be decarbonized, their carbon sourcemust be of biomass origin or atmospheric CO2. In the
production of new fuels, it will be necessary to use
production that takes advantage of the characteristics ofeach country and, in countries with large production
potential, to create production plans not only for their own
use but also for export in order to realize a decarbonizedsociety for the entire world.

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G. HIBINO et al.

5.3 Response to Negative Emissions
In Asia, especially in Southeast Asia, there arecountries with abundant forest resources. In suchcountries, expansion of forest sinks is incorporated into
their strategies to achieve carbon neutrality. For example,
Indonesia and Thailand, in their long-term strategies,
expect to absorb 300MtCO2 or 120MtCO2 in 2050,
respectively (Indonesia, 2021; Thailand, 2022). On theother hand, some countries are not expected to absorb
much from forests due to climate and land area. Therefore,
countries with abundant forest resources are expected totake measures to use these resources not only to reducethe burden of their own energy-related CO2 reduction
measures, but also as offsets for resource-poor countries
and regions.
In addition to forests, negative emission measures
include soil carbon sequestration, blue carbon, biomass
CCS, and other measures that incorporate natural uses, aswell as DAC, which captures CO2 directly from theatmosphere through chemical reactions. These measures
are also expected to take advantage of the characteristicsof the natural environment, not only within each country,
but also for decarbonization of the world as a whole.
5.4 Necessity of Social Transformation
Our analysis of Japan suggests that achieving socialtransformation will increase the certainty of achieving adecarbonized society. There are countries in Asia that are
currently still in the developing stage, where material
demand will increase significantly in the future due toimproved capital development and the diffusion ofdurable consumer goods. For example, per capita steel
consumption (production + exports - imports) in Japanand China exceeded 500 kg in 2018 (Japan 560 kg, China
609 kg), while in Thailand and Vietnam, consumption was
about half that amount (Thailand 322 kg, Vietnam 262 kg),and in India and Indonesia it was about one-eighth (India
77 kg, Indonesia 68 kg) (World Steel Federation, 2019).
In 2020, per capita car ownership was 0.62 in Japan, 0.20
in China, 0.28 in Thailand, 0.11 in Indonesia and 0.05 in
India (estimated from JAMA, 2022 and UN, 2022), with
India’s less than one tenth of Japan’s. For the least
developed countries, building social capital for efficientmaterial use and creating cities that do not become
car-dependent will, in the long run, lead to a shortcut
toward a decarbonized society.

Summary
The realization of a decarbonized society will require
efforts to achieve zero emissions from all emission
sources as well as a drastic transformation of the energy
consumption mix. Our analysis shows that promotingsocial transformation will substantially increase thepossibility of achieving a decarbonized society.

Acknowledgments
This research was performed under the Environment
Research and Technology Development Fund (JPMEERF
20201002) of the Environmental Restoration andConservation Agency Provided by the Ministry ofEnvironment of Japan.
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Go HIBINO
Go Hibino received his master’s degree from the
Graduate School of Science, Tokyo University of
Science. From 1991, he worked at the now Mizuho
Information & Research Institute, Mizuho Research& Technologies, Ltd. He has served in his current
position since July 2020. Since the early 1990s, hehas been involved in the Asia-Pacific Integrated
Model (AIM) Development Project, primarily with the development of
AIM/Enduse and its application to Japan. He has also been a long-time
contributor to reviews on Japan’s emission reduction targets and reductionplans. He is currently the research collaboration coordinator (Asia-PacificIntegrated Model) for the Decarbonization Measures Assessment Section,
Social Systems Division, National Institute for Environmental Studies(NIES).

Shuichi ASHINA
Dr. Ashina received his Ph.D. from the Graduate
School of Engineering, Tohoku University in 2006.
He joined NIES in 2006 and served as a seniorresearcher and manager in the International
Coordination Office. Since April 2021, he has been
Principal Researcher in the Regional Planning
Section, Social Systems Division. His specialty ismechanical and system engineering. As a member of the Asia-PacificIntegrated Model team, his research addresses decarbonized societies andcities in Japan and other Asian countries, along with roadmaps forrealization. He also has contributed to deliberations on decarbonization
planning and developing policies including as a member of government
advisory groups. In recent years he has also worked on ICT/IoT and
AI-based approaches and their application to climate change mitigation
research.

21

Diego SILVA HERRAN
Dr. Silva Herran received his Ph.D. from the
Graduate School of Engineering, Department ofManagement Science and Technology, Tohoku
University in 2010. He specializes in energy systemanalysis for sustainable societies and environmental
issues focusing on climate change mitigation
scenarios. For AIM, he uses GIS data to assess
renewable energy resources and analyzes national and global climatechange mitigation scenarios using integrated assessment models. He
currently serves as senior researcher in the Decarbonization Measures
Assessment Section, Social Systems Division at NIES.

Toshihiko MASUI
Prof. Masui received his Ph.D. from the Graduate
School of Engineering Osaka University. He joined
NIES as a researcher in 1998. He has held his
current position since April 2022 after serving as
senior researcher and director. He has a concurrent
appointment as a visiting professor at the Tokyo
Institute of Technology School of Engineering. His
research focuses on development of the Computable General Equilibrium
Model, one of the component models of the Asia-Pacific Integrated Modelbeing developed at the National Institute for Environmental Studies, andapplication of the model to assessing climate change mitigation measures.
Prof. Masui currently serves as Social Systems Division Director at NIES.

Yuko MOTOKI
Dr. Motoki received her Ph.D. in policy andmedia. She is responsible for energy supply anddemand analysis for the National Institute forEnvironmental Studies’ AIM project, research on
implementation of carbon pricing in Japan andoverseas, support for review committee operation,
including that of the Central Environment
Council’s subcommittees as well as lecturing andconsulting for private sector companies. She currently serves as chief
consultant for Sustainability Consulting Division 1 at Mizuho Research &Technologies, Ltd.

Tomoki HIRAYAMA
Tomoki Hirayama is a meteorologist engaged
mainly in supporting formulation of the Ministry of
the Environment’s mid- to long-term plans andresearch with the National Institute forEnvironmental Studies’ AIM project. His work
includes estimating GHG and air pollutant
emissions using energy supply and demand andtechnology selection models and analyzing theemission reduction effectiveness of measures and policies. He is currently
senior consultant for Sustainability Consulting Division 1 at Mizuho
Research & Technologies, Ltd.

Takaharu OTA
Takaharu Ota is a consultant for the Sustainability
Consulting Division of Mizuho Research &Technologies Co., specializing in quantitative
analysis using models. His research with the
National Institute for Environmental Studies AIM
project includes the use of energy supply anddemand, technology selection models for estimating emissions, and investigation of innovative
decarbonization technologies, such as the use of hydrogen for direct
reduction ironmaking.

(Received 14 October 2022, Accepted 28 December 2022)