LONG-TERM SCENARIOSFOR DECARBONIZING JAPAN
Executive Summary
WWF Japan (Feb 2017)

KEY POINTSWWF Japan analyzed long-term scenarios for energy and the potential for greenhouse gas emission
reductions, based on an assumption that Japan would be a forerunner among countries to achieve
decarbonization as called for under the Paris Agreement. Specifically, the following two WWF
scenarios were considered.
ØØ100% Renewable Energy Scenario: This scenario assumes that in 2050, all of Japan's
energy is supplied by renewable energy sources.
Bridge Scenario: This scenario assumes that the government's official target of an 80%
reduction in greenhouse gas emissions by the year 2050 is achieved. This is called the"Bridge Scenario" to reflect its role as a bridge to the 100% renewable energy scenario.

2030

2050

2030

Bridge100%
renewables

100%
Govt's 2015 long-term
renewables supply-demand outlook

BridgeEnergy efficiency (reduction of FEC, compared to 2010)

16%

21%

39%

47%

14%

Renewable energy (share of primary energy)

22%

39%

74%

100%

13–14%

GHG emission reduction (compared to 2010)[compared to 2013]

26%
[32%]

42%
[46%]

81%
[82%]

95%
[95%]

20%
[26%]

Results of the analysis for the 100% Renewable Energy Scenario can be summarized as follows.
ØJapan's final energy consumption (i.e., demand) can be reduced to about half by 2050 (47%
reduction below 2010 level), based on currently-foreseeable penetration and advances inenergy efficiency technologies and measures. This is certainly not an unrealistic scenario.
For example, for energy efficiency in major industries in the industrial sector, the scenario
assumes efficiency improvements of 20% to 30% over approximately the next 40 years to
2050. All housing and at least 40% of buildings are assumed to at least meet today's latest
energy efficiency standards. And it is assumed that all vehicles will shift to electric and fuelcell vehicles (EVs and FCVs), which are already starting to become more popular.

Ø

The above-mentioned energy demand in 2050 is within the realm of Japan's potential
supply of renewable energy. If the share of renewable energy is assumed to follow a
straight-line increase to 100% of the energy mix in 2050, then in 2030, renewable energy
must supply 37% of electricity (share of "pure" electricity demand; details below), and 39%of the primary energy supply.

Ø

Renewable energy supplies (especially wind power and photovoltaic) are sometimes said tobe difficult to match with electricity demand, due to power output fluctuations. However,the simulation conducted in this scenario study indicates that 100% of demand in 2050
could be continuously met with renewable energy sources, 365 days a year. To do so,
however, a unified national electricity grid would be essential, and a two-to-one ratio ofphotovoltaic to wind power generation would be desirable.

ØConsidering the big picture for energy, the supply of renewable energy to meet electricity
demand is theoretically not a major issue. Rather, the challenge is finding how to meetdemand for heat energy and fuels. For this challenge, the keys will be to significantly
expand the use of biomass, to use surplus electricity to produce hydrogen, and to utilize thathydrogen.

Ø

Achieving this scenario will require capital expenditures (CapEx) of 365 trillion JPY (3.3
trillion USD) over approximately 40 years (2010 to 2050), but this would be offset by areduction (i.e., savings) in operating expenditures (OpEx) amounting to 449 trillion JPY(4.1 trillion USD), which means a net savings (Net) of 84 trillion JPY (0.8 trillion USD).

ØIn 2050, CO2 emissions from energy will ultimately become zero, and greenhouse gas
emissions will have decreased by 95%.

The Bridge Scenario envisions a somewhat delayed achievement of the 100% Renewable Energy
Scenario. Energy efficiency goals are achieved with a delay of about five years, and the renewableenergy supply goals with a delay of about ten years. The basic features of this scenario can besummarized as follows.
Ø

The penetration of energy efficiency technologies and measures results approximately in a
40% reduction in energy consumption in 2050 compared to 2010.

Ø

In 2050, renewable energy provides approximately 74% of the primary energy supply, andabout 90% of electricity ("pure" electricity basis; details below). In 2030, it provides about
22% of the primary energy supply and about 37% of electricity.

Ø

In 2050, of the "remaining 20%" of emissions from fossil fuels, coal is used for blast furnacesteel production and oil is used for heat demand in various industries including chemical
production, and for aviation fuel, while gas supplies heat demand in the household andcommercial sectors.

ØAchieving this scenario will require capital expenditures (CapEx) of 296 trillion JPY (2.7
trillion USD) over approximately 40 years (2010 to 2050), but this would be offset by areduction (i.e., savings) in operating expenditures (OpEx) amounting to 392 trillion JPY(3.6 trillion USD), which means a net savings (Net) of 96 trillion JPY (0.9 trillion USD).

2ASSUMPTIONS AND METHODOLOGY
The list below summarizes the assumptions and analytical steps used in both WWF scenarios.
1. Assume significant reductions in energy demand through energy efficiency, based onassumptions about currently-foreseeable advances in technologies and measures.
2. Assume the gradual phase-out of nuclear power.
3. Consider how demand can be met, based on consideration of the potential available foreach type of renewable energy sources.
4. Separately, use Dynamic Simulation based on meteorological and other data to see whether
renewable energy and other sources can supply fluctuating power demands 24 hours a day, 365
days a year, in 2050.
5. Assume the gradual phase-out of fossil fuels based on the progress described above.
One major difference between the WWF scenario and other similar energy scenarios is the approach
to using renewable energy. The WWF scenario envisions not only supplying all electricity withrenewable energy sources in the future, but besides electricity, also meeting demand for heat and fuelsby using hydrogen produced with surplus electricity (it also assumes to meet demand for heat andfuels with biomass, solar heat, and other sources). This approach also makes it possible to resolve theissue of surplus electricity from fluctuating renewable sources, and at the same time to meet demandfor heat and fuels.

ENERGY DEMAND: HOW MUCH CAN ENERGY EFFICIENCY REDUCE?
Steps to consider the potential for energy efficiency
The WWF scenarios consider the potential for improvements in energy efficiency, based on thefollowing steps.
1. Determine typical energy efficiency measures and technologies in each sector (i.e., industrial,households, commercial, transport), and consider the pace of energy efficiency improvements(e.g., improved performance and large-scale deployment of LED lighting).
2. Calculate energy demand based on the contribution of each technology and measure to energy
consumption reduction, by sector and by use (e.g., by sector—household; by use—lighting, hotwater supply). (For activity levels, individual assumptions are specified separately; e.g., using
ratio of population to calculate number of vehicles). The following equation is used:
Final energy demand (by use) in year T= 2010 final energy demand (by sector and by use) x
Change in activity level from 2010 (by sector) in year T x
Pace of improvement in energy efficiency in year T
3. Add up energy consumption in all sectors and categories to produce the total energy
consumption.

Results: The potential for energy efficiency
For the society-wide activity levels, the scenarios make assumptions that trends, such as apopulation decline to 76% of the 2010 level and a shift toward sustainable society, lead to a 20%
reduction in activity level for resource consumption compared to 2010. Accordingly, as in many otherenergy scenarios, the energy consumption decreases even in the business as usual (BAU) case to 2050.
3

Under the WWF scenarios, with energy efficiency increased by additional 20–30%, a reduction inenergy demand as outlined below is possible (Assumptions for technologies and measures in specificsectors are described further below).
Under the 100% Renewable Energy Scenario, it is possible to reduce energy consumption in
2050 by 47% compared to 2010, and by 42% compared to the business as usual case (based on final
energy consumption). In terms of amount, the industrial sector will have the largest reduction, but interms of percentage, the transport sector will be the largest. The following two graphs show the
reduction amount and percent from the BAU scenario.

Reducedconsumption

Under the Bridge Scenario, improvements in energy efficiency reduces energy consumption in
2050 by 39% compared to 2010, and by 34% compared to the BAU scenario (based on final energy
consumption). As in the 100% Renewable Energy Scenario, the largest reduction is in the industrial
sector, but in terms of percentage, the reduction in the transport sector is the largest. Compared to the
100% renewable scenario, the annual rate of improvement in energy intensity (final energy
consumption per unit of real GDP) is slightly lower (2.6% for the 100% Renewable Energy Scenario
versus 2.3% for the Bridge Scenario). This is about the same level as Japan's actual rate of
improvement in the past (1970 to 1990) at 2.3%. In addition, with population decline and other4

factors, even in the BAU scenario during the same period, the average annual rate of improvement inenergy intensity is 1.3%, so if we take Japan's energy efficiency potential into account, the Bridge
Scenario would be quite achievable.

Key energy efficiency measures and technologies
The WWF scenarios envision energy efficiency technologies and measures like the ones indicatedbelow. The scenarios are based on factors such as the currently-foreseeable penetration oftechnologies, and can be fully achieved even without excessive reliance on innovative technologies.
SectorExamples of technologies and measures

Industry

Inverter controls on pumps, inverter controls on fans, iron/steel recycling

Household

Promotion of zero energy houses (ZEH), heat pumps, and LED lighting,more efficient electric refrigerators, reduced standby energy consumption

Commercial

Promotion of zero energy buildings (ZEB), replacement of hard-disk storage
in data centers with flash memory

Transport

Promotion of eco-friendly driving, car sharing, electric vehicles (EV), and fuelcell vehicles (FCV)ENERGY SUPPLY: MOVING TOWARD 100% RENEWABLE ENERGY
For renewable energies, based on a study by Japan’s Ministry of the Environment regarding theirpotentials, certain constraints are applied for the actual amount of renewable energies utilized, withconsideration given to their sustainability.
For this scenario, "renewable energy" is defined to include, among other types, hydroelectric (ofwhich only small and medium hydro is expected to increase), photovoltaic, wind power, geothermal,
biomass (heat and electricity), wave power, and solar heat.

Electricity supply
For electricity, since photovoltaic and wind power have large future potential, their shares are
assumed to increase. In order to supply electricity continuously 365 days a year, the simulation showsthat a desirable proportion of photovoltaic to wind power would be approximately two to one. Thus,
the WWF scenarios assume that same proportion in the supply in 2050.
Also, the WWF scenarios assume that a portion of heat and fuel demand is supplied by electricity
from renewable energy sources. There are two approaches for this. One is to use electricity to replaceheat and fuel demand, which until now has largely been supplied by sources such as gasoline and gas.
Examples include electric vehicles and air conditioning by heat pumps.
Another approach is to use electricity to produce hydrogen, and then meet demand for heat and fuel(including fuel cell vehicles) using that hydrogen. It is assumed that all surplus electricity is used to
produce and store hydrogen, so that the fluctuating electricity supply from renewable sources can beutilized effectively, even during time slots when the amount of electricity generated exceeds demand.
This strategy has enormous merits in terms of electricity grid operations.
The following graph shows the electricity supply under the 100% Renewable Energy Scenario.
It includes electricity for the production of hydrogen for fuel use, as described above. Toward 2050,"pure" electricity demand declines by about 40% from 2010 due to factors such as population decline
and improved energy efficiency, but electricity generation itself is maintained at about the same level
as today if the proportion of electricity used to provide heat and fuel is included. At the midpoint in
2030, the renewable energy share is approximately 37% of "pure" electricity, and approximately 45%
of electricity supply if we include generation for heat and fuel uses. Photovoltaic and wind power are
major sources in that mix.
5

The Bridge Scenario assumes some gas use remaining even in 2050. Specifically, gas is assumed
to supply 8% of electricity including for heat and fuel uses, and 10% of "pure" electricity. The reason touse gas (as opposed to oil and coal) in this scenario is that it emits less CO2 to obtain the same amountof electricity, and can also respond flexibly to fluctuations in renewable energy supply. However,conversely, even in the Bridge Scenario, there is a need to decarbonize approximately 90% of theelectricity supply in 2050. At the midpoint in 2030, the renewable energy share is approximately 37%
of "pure" electricity, and approximately 43% of electricity supply if generation for heat and fuel uses is
included.

Electricity generation (TWh)
2010

2020

2030

2040

2030

2050

2030

25%
9%

0%
0%

22%
8%

100

0

24%

0%

21%

0%

105
0

135
0

13%
4%

22%
0%

11%
4%

14%
0%

Oil

250
90

190
70

66
55

Gas

233

210

180

Hydro

83
288

90
108

97
33

Nuclear

2050

Share
(incl. heat &fuel uses)

0
0

322
107

Coal

Share
("pure"electricity)

2050

0%
0%

Geothermal

3

4

7

37

61

1%

10%

1%

6%

Biomass
PV

15
0

23
50

32
98

42
150

45
235

4%
13%

7%
38%

4%
11%

5%
24%

Wind

0

16

40

66

118

5%

19%

5%

12%

Wave

0
1,051

0
840

0
747

13
635

26
0%
621 100%

4%
100%

0%
86%

3%
63%

PV for heat & fuel

0

15

80

160

245

9%

25%

Wind for heat & fuel“Pure” electricity total

0

8

40

95

122

5%

12%

Total electricity, incl.
heat & fuel uses

1,051

863

867

889

988

100%

100%

Renewable energy total("pure" electricity)

101

182

274

414

621

Renewable energy total(incl. heat & fuel uses)

101

205

394

668

988

45%

100%

6

37%

100%

Primary energy supply
In the 100% Renewable Energy Scenario, just as in the case in which only electricity is
considered, the proportion of wind power and photovoltaic generation increases, but to respond toheat and fuel demand, the role of biomass increases (to approximately 20% of total energy in 2050). In
addition to biomass and solar heat, it is also assumed that hydrogen produced by photovoltaic andwind power is utilized. At the midpoint in 2030, renewable energy has a 39% share of the total.
For the Bridge Scenario, coal is used for blast furnace steel production, oil for thermal heat
demand in various industries including chemical production and for aviation fuel, while gas supplies
heat demand in the household and commercial sectors. As a result, in 2050, renewable energy has a
74% share, while, coal, oil, and gas still have a 6%, 8%, and 12% share, respectively. At the midpoint in
2030, renewable energy has a 22% share of the total energy supply.

Primary energy supply (PJ)
2010

2020

2030

2040

Share
2050

2030

2050

Coal
Oil

4,981
8,819

4,076
7,474

2,814
5,009

1,443
2,657

0
0

16%
29%

0%
0%

Gas

4,243

3,682

2,380

1,278

0

14%

0%

Hydro
Nuclear

747
2,322

810
801

873
207

949
0

1,215
0

5%
1%

11%
0%

Geothermal

28

33

66

331

552

0%

5%

Biomass
PV

153
20

938
794

1,500
2,890

1,778
3,900

2,200
4,316

9%
17%

19%
38%

Wind

29

397

1,260

1,946

2,167

7%

19%

Wave
Solar heat

0
0

0
20

2
120

118
444

237
600

0%
1%

2%
5%

22,15719,025

17,122

14,844

11,287

976

2,992

6,711

9,466

11,287

39%

100%

Total
Total renewables

7

COSTSIn the 100% Renewable Energy Scenario, total capital expenditures over the 40 years from2010 to 2050 come to 191 trillion JPY [1.7 trillion USD when 1USD=110JPY] for energy efficiency and
174 trillion JPY [1.6 trillion USD] for renewable energy, totaling 365 trillion JPY [3.3 trillion USD].
However, the promotion of energy efficiency and expansion of renewable energy end up limiting fossil
fuel consumptions, resulting in a significant decline in facility operating costs, which, in turn,generates savings. The amount of savings comes to 281 trillion JPY [-2.6 trillion USD] for energy
efficiency and 168 trillion JPY [-1.5 trillion USD] for renewable energy, totaling 449 trillion JPY [-4.1
trillion USD]. Thus, the net cost over 40 years comes to a total of minus 84 trillion JPY [-0.8 trillion
USD]. In other words, this is a net benefit of 84 trillion JPY [-0.8 trillion USD].
The Bridge Scenario is similar. Total capital expenditures over the 40 years from 2010 to 2050
come to 156 trillion JPY [1.4 trillion USD] for energy efficiency and 143 trillion JPY [1.3 trillion USD]
for renewable energy, totaling 299 trillion JPY [2.7 trillion USD]. Cost savings from the promotion ofenergy efficiency and expansion of renewable energy come to 242 trillion JPY [-2.2 trillion USD] forenergy efficiency and 146 trillion JPY [-1.3 trillion USD] for renewable energy, totaling 388 trillion JPY[-3.6 trillion USD]. The net cost over 40 years comes to a total of minus 90 trillion JPY [-0.8 trillion
USD]. In other words, this is a net benefit of 90 trillion JPY [-0.8 trillion USD].
These calculations were based on a period of 40 years to estimate investment and returns, but in thereal world of capital investment, it is rare to see investments planned over such a long time period.
Thus, it will be important to introduce policies that offer incentives to encourage investment andproduce these kinds of benefits in the long term.
Expenditures(trillion JPY)
[trillion USD; 1USD=110JPY]

100% Renewable Energy Scenario

Bridge Scenario

CapitalOperatingNet

CapitalOperatingNet

Energy efficiency

191
[1.7]

-281
[-2.6]-90[-0.8]

156
[1.4]

-242
[-2.2]-86[-0.8]

Renewable energy

174
[1.6]

-168
[-1.5]+5.9[+0.05]

143
[1.3]

-146
[-1.3

-3.5
[-0.03]

Total

365
[3.3]

-449
[-4.1]-84[-0.8]

299
[2.7]

-388
[-3.5]-90[-0.8]* Some numbers don't add up due to rounding.”

GHG EMISSIONS
Under the 100% Renewable Energy Scenario, unsurprisingly, energy-related CO2 emissions drop to
zero. With other non-CO2 gases considered, greenhouse gas emissions ultimately decline byapproximately 95% in 2050. At interim points in 2020 and 2030, for the 100% Renewable Energy
Scenario, the reductions compared to 2010 are approximately 16% and 42%, respectively (orapproximately 14% and 40% compared to 1990, or 22% and 46 compared to 2013).
Under the Bridge Scenario, in 2020 and 2030, the reductions compared to 2010 are
approximately 7% and 26%, respectively (or approximately 4% and 24% compared to 1990, or 14% and
32% compared to 2013).

8

LONG-TERM STRATEGY FOR A “DECARBONIZED SOCIETY” IN JAPANTo achieve the 100% Renewable Energy Scenario or the Bridge Scenario, certain assumptions are
made for the calculations. Conversely, one could say that these assumptions must be achieved in orderto realize the scenarios. Below is a selection of the most important assumptions.
In this report, the Bridge Scenario is presented as a scenario on the path to achieve the 100%
Renewable Energy Scenario; thus, essentially, there are no major differences in the criteria to achieve
either one. In fact, supplying 100% of electricity from renewable energy sources is an extension oftechnologies that already exist, so realization of this goal is entirely within the realm of possibility.
However, some prospects are still not fully known, such as the potential to fully use renewable energy
for heat and fuels, as well as certain industrial processes such as iron- and steelmaking. In this regard,
the Bridge Scenario has shown that an 80% reduction in 2050 at the latest is entirely achievable, as it
still includes the use of gas in the electricity sector, and permits gas, oil, and coal in sectors where it iscurrently difficult to find alternatives. Nevertheless, for the long-term planning to 2050, it is necessary
to present an ambitious vision such as the 100% Renewable Energy Scenario to accelerate processes toachieve decarbonization.
Below is a set of some major conditions to be achieved, considering the assumptions used to create
the scenarios.

Energy efficiencyØØØPromotion of energy efficiency for housing and buildings (e.g., ZEH, ZEB): By
2050, nearly all housing and about 40% of buildings other than housing meet today's latest
energy efficiency standards.
More efficient industry and promotion of metal recycling: Material manufacturingindustries aim to increase efficiency by 20–30% over approximately 40 years from 2010 to2050. Also, iron and steel industries, the largest emission sources in the industrial sector,
aim to increase the proportion of electric furnaces being used with a target of approximately
70% and contribute to emission reductions.
Accelerated penetration of EVs and FCVs: By 2050, nearly all vehicles are electricvehicles or fuel-cell vehicles. This requires more than half of vehicles operating in the 2030s
to be EVs or FCVs.

9

Renewable energyØØØReform of power grid operations: Reform power grid operations with a real priority
given to the use of renewable energy.
Development of hydrogen infrastructure based on renewable energy: Install
infrastructure to produce hydrogen using surplus electricity from renewable energy sources.
Full-scale utilization comes around 2030 approximately.
Expanded use of heat from biomass: Develop systems to enable sustainable biomass
supply at the level of 60 million m3 per year in total.

Phasing out fossil fuelsØØCarbon pricing of fossil fuels: As part of the capital investment required by the
scenarios, some items will take time to recover the investment. For the scenarios, a carbon
price has not been explicitly provided, but in order to induce more capital investment for
decarbonization, carbon pricing needs to be introduced, with emissions trading (cap andtrade) in particular.
Decarbonization of electricity sector (in particular, phase out of coal-fired
power plants): It is necessary to decarbonize the electricity sector faster than othersectors. For example, coal-fired power generation decreases by more than 40% from 2010
to 2030. If power generation efficiency remains unchanged, generation capacity needs todecrease by about that amount, so new construction of coal-fired plants would be unlikely.
On this point, there is no difference between the 100% Renewable Energy Scenario and theBridge Scenario.

Gradual phase-out of nuclear powerØ

Articulation of policies to gradually phase out nuclear power: In principle,
nuclear is phased out after they reach thirty-year lifetime. As for the existing plants,
immediately phase out those that are not able to meet new safety standards, and those that
do not have consent of the local community.

Contact:
WWF Japan Climate and Energy Group
Nihonseimei Akabanebashi Building (6th Floor), 3-1-14 Shiba, Minato-Ku, Tokyo 105-0014 Japan

Tel: +81-3-3769-3509 / Fax: +81-3-3769-1717 / Email: climatechange@wwf.or.jp
The full report (only in Japanese) can be downloaded from the WWF Japan website:
http://www.wwf.or.jp/re100_2017/10