11

Transitions of Energy Systems and Technologies toward
Achieving the Paris Agreement in Japan
Shuichi ASHINA
National Institute for Environmental Studies (NIES)
16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japane-mail: ashina.shuichi@nies.go.jp

Abstract
In order to achieve the targets in the Paris Agreement, it is important to reduce greenhouse gas (GHG)
emissions drastically. Because in Japan most GHG emissions result from energy consumption (88.6% in2015), de-carbonization of energy systems is crucial, and there are strong hopes for technological innovationin energy supply and demand to help the targets be reached. Japan has already undertaken various kinds oftechnological development and implementation in society via both the public and private sectors, and these
activities have contributed to the reduction of energy consumption and GHG emissions in Japan. For
example, the total energy consumption in the latter half of the 1990s and first half of the 2000s was around550－560 million tons of oil equivalent (Mtoe), decreasing to 502 Mtoe in 2015 through comprehensive
energy saving measures and actions to reduce GHGs. Even so, development of innovative technologies isstill needed for further GHG emission reductions. In the past, technological measures focused on devices
such as those involving hydrogen, carbon capture and storage, or batteries and renewables, but research anddevelopment (R&D) is now focused on systemized technologies. One example is energy monitoring systems
in conjunction with energy management, and another is local energy networks with renewables anddistributed energies such as gas cogeneration and biomass boilers. Low carbonization of energy systems is
the key to both GHG emission reduction and achieving a global low-carbon society. Materialization of
innovative technologies is also needed for building a low-carbon society, and Japan’s experience andexpertise in technological R&D could be the first step in the right direction and will go a long way toward
providing a foundation for impressive GHG emission reductions and establishment of a low carbon-society
not only in Japan but also all over the world.
Key words: c limate change mitigation, emission reduction, energy system, system transition,technology development

1. Introduction: Historical Transition in Japan’s
Energy Sector
The value of a “stable climate” as an environmental
commodity has increased. An important feature of theclimate system is its inertia. Because of past and current
greenhouse gas (GHG) emissions, a certain increase inglobal temperatures is unavoidable, as reported in the
IPCC’s Fifth Assessment Report (AR5). Such increases
in temperature carry profound risks. Even a small
increase in temperature is likely to have significant
impacts on ecosystems and species, and might lead toincreased droughts or extreme rainfalls, with severe
consequences for our society. Measures against global
warming need to be taken to ensure sustainable
development and a better future for Japan. The scientificinformation in AR5 and many international agreements
and commitments including the Paris Agreement
Global Environmental Research
21/2017: 011–021
printed in Japan

indicate the profoundness of global warming and theneed for prompt action. As Japan is no exception, in thatit seems to have been affected in various ways by global
warming, it is time to implement concrete measures inview of disaster prevention, health, water resources,
food, ecosystems, etc., while reducing GHG emissions.
A response to this challenge can be found intechnology development, which is Japan’s area ofexpertise. As such, the perfect opportunity for a new
growth driver can be found right before our eyes.
Competition has already begun. Competition can beovercome by creating low-carbon technologies andsocial systems that have no equal. The key is to takepositive action and not wait around doing nothing.
In order to cut greenhouse gas (GHG) emissions toachieve the low-carbon society indicated in the Paris
Agreement, it is important to understand sources of
GHG emissions and identify causes (or driving forces)©2017 AIRIES12

S. ASHINAof emissions. Based on the IPCC Inventory Guideline,
sources of GHG emissions can be divided into six
categories: (1) energy use, (2) industrial processes, (3)agriculture, (4) waste, (5) land-use change and forestry(LUCF) and (6) bunker fuels. Among these categories,
in Japan, GHG emissions from energy use have adominant share compared to the other categories. In
2015, 88.6% of Japan’s GHG emissions came fromenergy use (NIES/ GIO 2017). GHG emissions fromenergy use have a strong relationship with primaryenergy consumption and level of economic activity, so
getting a picture of GHG emissions from energy use isalmost equal to understanding energy systems andenergy consumption.

1.1 Overview of Energy Profiles in Japan
Figure 1 summarizes energy consumption by primaryenergy source in Japan from 1880 to 2015. Until around
3.11

30
25

NUC

Oil Crisis

20

GAS

15
10
5
0
1880

1900

1920

OIL

COAL

1880
Period:

1895
Meiji

Renewable and Others

1910 1925|Taisho|
Nuclear

1940
Gas

1955 1970
Showa
Oil

Coal

1985
|

Hydro

2000 2015
Heisei

Traditional Biomass

Fig. 1 Long history of energy consumption in Japan, by primaryenergy source (EDMC, 2017).

1880, energy consumption in Japan mainly consisted of
traditional biomass such as fuel wood and charcoal.
Then coal use started to grow and Japan kept coal as amain source of energy until the end of World War II.
Before the two oil crises of 1973 and 1979, energy
consumption, especially oil consumption, increased witheconomic growth. After the latter half of the 80s, i.e., thebeginning of the bubble economy, energy consumption
started to increase again due to the upturn in economic
activity, interfusion with an energy-consuming lifestyleand shift in vehicle preferences to large cars such as land
cruisers. After the bubble economy burst in the latter
half of the 90s, Japan’s prolonged economic slump led
to suppression of energy consumption, and total energy
consumption remained at a level of around 550－560
million tons oil equivalent (Mtoe) for a while after that.
The bankruptcy of Lehman Brothers and subsequentrecession have affected not only economic activity but
also energy consumption, and energy consumption in2009 was 487 Mtoe, down 7% from the 2008 level.
Among energy sources, we should give more
attention to nuclear energy in Japan. Nuclear power wasa key technology for the electricity supply in Japan after
the oil crisis, because Japan’s energy policy aimed todiversify energy sources away from oil. On March 11,
2011, Japan suffered a big earthquake and tsunami. The
nuclear power plants in the northern part of Japan’s mainisland have been now shut down since. On that day, 55
nuclear power units were in commercial operation and
12 units were under construction, as shown in Fig. 2. The
total installed capacity was 49,165 MW, and capacity
under construction, 16,318 MW. The Okinawa ElectricPower Co. (OEPC) has no nuclear power facilities andno future plans to construct any. When the earthquake
hit, 15 plants were shut down in response. Subsequently,

Fig. 2 Locations of nuclear power plants in Japan (EDMC, 2017 and author).

13Transitions of Energy System and Technologies in Japan
300.0
Air condi�oner

Refrigerator

TV

PC

1995

2000

Ownership rate [%]

250.0

200.0

150.0

100.0

50.0
1965

1970
Industrial

1975

1980

1985

1990

Residen�al

1995

2000

2005

2010

2015

Commercial

0.0
1970

1975

1980

1985

1990

2005

2010

2015

Fig. 3 Final energy consumption, by sector (EDMC, 2017).

Fig. 4 O wnership rates for typical home appliances from 1970 to2003 (EDMC, 2017).

the Tohoku Electric Power Co. (Tohoku-EPCO) shut
down all its nuclear power plants (Onagawa: 2,174 MW
and Higashi-dori: 1,100 MW). The Tokyo ElectricPower Co. (TEPCO) also shut down some of its nuclear
power plants on account of the earthquake, but only
plants on the Pacific side of Japan (Fukushima Daiichi:
4,696 MW and Fukushima Daini: 4,400 MW). By 2014,
all of Japan’s nuclear power plants had been shut down
for periodical inspection and never restarted within theyear. Thus, Japan generated no nuclear-power electricity
in the year 2014. Since 2015, some nuclear power plants
located in the western part of Japan have been approvedfor restarting on the condition that they conform tostrengthened safety criteria set by the Nuclear andIndustrial Safety Agency.
In terms of final energy consumption in Japan, total
final energy consumption has shown a similar trend to
primary energy consumption, as shown in Fig. 3. The
industrial sector, especially the manufacturing industry,accounts for a large part of final energy consumption
during the entire period covered by the statistics. In
2015, the total final energy consumption was 316 Mtoe,
with the industrial sector (manufacturing andnonmanufacturing industries) consuming 149 Mtoe,
which corresponds to 47.1% of the total final energy
consumption. However, final energy consumption in theindustrial sector after the oil crises has remained almost
steady at around 150－160 Mtoe and its share of the total
final energy consumption has gradually decreased. The
increase in final energy consumption has come mainly
from increases in final energy consumption in both theresidential and passenger transportation sectors.
In 1965, final energy consumption in the residential
and passenger transportation sectors was 11 Mtoe and 8
Mtoe, respectively. In 2015, the residential sector
consumed 47 Mtoe, which corresponded to 4.4 times the
final energy in 1965, and the passenger transportation
sector consumed 49 Mtoe, 6.2 times the 1965 level. This
is why, especially after the bubble economy started,
lifestyles in Japan shifted toward higher energyconsumption, such as greater varieties of home
appliances, multiple appliance and vehicle ownership,larger sizes of appliances and trends in vehicle
preferences for larger cars. As an illustrative example,
changes in ownership rates for typical home appliances(air conditioners, refrigerators, TVs and PCs) from 1970
to 2015 are summarized in Fig. 4 (some statistical data
after 2004 are unavailable due to a change in thestatistical survey system). More than 100% ownershipindicates that the average household has several units of
the appliance, e.g., 200% ownership of air conditioners
could be interpreted to mean that each household has
installed two air conditioning systems at home. The
figure clearly shows that except for refrigerators,
ownership rates continue to grow. That is, final energy
consumption also continues to grow.

1.2 H
 istorical Transitions of the Energy System in Japan
In the 135-year history of energy statistics in Japan,
we can find at least two energy system transitions (ortechnology shifts). Specifically, one occurred after theoil crisis and the other, after the March 2011 earthquake.
The oil crisis triggered the promotion of non-oil
energy sources such as gas and nuclear, as describedabove, and popularization of energy-saving activities,
including replacement by energy efficient machines orappliances in all sectors, including industrial, residential,commercial and transportation. Although this transition
brought another type of energy system into Japan—theelectrified society— that transition is not yet complete,because even now, oil still accounts for around 45% ofprimary energy consumption in Japan, as shown in Fig. 1.
The accidents in Fukushima following the March2011 earthquake led nuclear power to be shut down forthorough safety review. As a result, nuclear was fully
substituted for by fossil fuels in 2014. Some nuclear
plants, however, have restarted after safety examinations
and approval by the government since 2015, so theenergy transition from nuclear to other energy resources
was not completed.
From the viewpoint of the energy transition in Japan,
even though diversification of fuel sources waspromoted after the oil crisis, oil has remained thedominant energy source consistently during the period

S. ASHINA

from 1965 to now. Before the oil crisis, energy demand
growth covered mainly oil. On the other hand, after theoil crisis, promotion of diversified energy sources
resulted in both suppression of oil consumption growth
and an increased gas and nuclear power supply. In asimilar way, before the Fukushima accident, nuclear
power was considered a key electricity supply and its
capacity grew in line with the Basic Energy Plan
designed by the Ministry of Economy, Trade and Industry(METI). On the other hand, the possibility of restarting
most nuclear power plants, except for a few such as
Fukushima Daiichi and Fukushima Daini, is being
explored after the complete examination of facilities.
As shown above, Japan has experienced two energy
system transitions triggered by the oil crisis andFukushima nuclear accident. Now, the Kyoto Protocol,
Paris Agreement and subsequent international agreements
on climate change mitigation are set to bring about athird energy system transition in Japan. The “low-carbon
society” philosophy aims to minimize carbon emissions
in all sectors as well as shift to a simpler, higher-quality
life and coexistence with nature. In order to realize sucha low-carbon society and/or energy system, new,innovative technologies are required not only for theenergy system but also the whole social system. The
needs for technological development cover wide-ranging
aspects, including the energy system, transportation,industry, buildings, energy efficiency, renewable energy,
lifestyle changes, education and awareness, governance,
forestconservation,
waste
management,
airenvironmental quality and urban planning. Even though,low-carbonization of the energy system is inevitable,
understanding of the energy system as well as actions
towards a low-carbon energy system offer hope. This
paper presents an outlook on technology development
before and after the Paris Agreement.

2. Current Technological Measures and Actions
for Climate Change Mitigation in Japan
Japan has tackled GHG emission reduction under acollaborative framework that includes government, local
authorities, industries, businesses, citizens and NGOs. In
October 1990, the Government of Japan ratified a plan
against global warming, named the “Global warming
action prevention plan,” in a ministerial conference on
global environmental conservation. The plan targetedstabilization of CO2 emissions at the 1990 level after theyear 2000. In 1997, the Third Conference of the Parties(COP) to the United Nations Framework Convention on
Climate Change (UNFCCC) was held in Kyoto where
the Kyoto Protocol was agreed upon. In the Kyoto
Protocol, the GHG emission reduction target for Japanwas set at a 6% reduction compared to the baseline year
from 2008 to 2012.
In June 1998, following the Kyoto Protocol
agreement, the Global Warming Prevention Headquarters
adopted “Guidelines for Measures to Prevent Global
Warming – Measures Towards 2010 to Prevent Global

Warming.“ At the same time, the Law Concerning thePromotion of the Measures to Cope with Global Warming
was enacted (Law No.117 of 1998) to set a basic
framework for actions to prevent global warming, andother relevant laws and measures, such as the Act on the
Rational Use of Energy, was revised. Since then, thegovernment of Japan has implemented various kinds ofpolicy measures, such as imposition of a tax for global
warming from 2012 and implementation of a feed-intariff (FIT) system for wholly renewable energy from
June 2012. In 2016, the Japanese government renewed
the National Plan for Coping with Global Warming, andsummarized three national GHG reduction targets: a
3.8% or more reduction from the 2005 level by 2020, a
26% reduction from the 2013 level by 2030, and an 80%
reduction by 2050.
Under these laws and plans, various kinds ofmitigation actions using technology have beenpromoted. Hybrid vehicles and electric vehicles, forinstance, have gradually diffused over these 10 years asshown in Fig. 5. In 1998, 3,428 hybrid vehicles and 638
electric vehicles were in use. The number of hybrid
vehicles in 2016 was 5,581,578 units, rising to 16.28
times the 1998 level. Although the increase in electricvehicles was small compared to that in hybrid vehicles,
63,760 units were in use in 2016. Such trends inpenetration can be found for other energy efficienttechnologies, such as LED light bulbs, heat pump water
heaters, solar heaters and efficient industrial furnaces.
Japan’s government and ministries have also
supported the spread of emission reduction technology
through policies and measures. For example, METI, theministry with jurisdiction over energy policy, creates
policies and measures for energy conservation, theKyoto Mechanisms, investment in innovative technology
and promotion of nuclear power. The Agency for Natural
Resources and Energy promotes a variety of energy
policies and measures in conjunction with METI. It has
been promoting the adoption of next-generation cokeovens and propagating high-performance industrial
furnaces in the industrial sector. The agency has
6,000,000

Hybrid vehicles

5,000,000

Electric vehicles
Number of Cars

14

4,000,000
3,000,000

2,000,000
1,000,000

0

1998

2000

2002

2004

2006

2008

2010

2012

2014

2016

Fig. 5 H istorical trends in penetration levels of hybrid and electricvehicles (Automobile Inspection & Registration Information
Association, 2017).

15

Transitions of Energy System and Technologies in Japanencouraged steady improvements in energy efficiency
equipment in the residential and commercial sectors
through a top runner approach, which sets standards forenergy efficiency. Under Japan’s Energy Conservation
Law, it promotes public relations activities, including
eco-labeling. In the transportation sector, it promotes
modal shifts and improved logistics efficiency.
Renewable energies such as wind and solar are a key
element for both energy policy and global warming
policy, and the agency has been funding technology
development and pilot projects.
In addition, it has also implemented technology
development programs. One example is a microgrid
demonstration project. Installation of renewables such as
solar, wind and biomass contributes to reduction of CO2
emissions and climate change mitigation. On the other
hand, burgeoning renewable generation has a nonnegligible negative impact on the grid system. The
output of renewable generation, especially solar andwind, is unstable, resulting in voltage and frequency
fluctuations in the power grid system. A microgrid(recently termed “smart grid”) is a localized group ofgenerators, storage cells, and electricity users connectedto the grid, that can function autonomously. Generators
include fuel cells, solar, wind, biomass, micro-gas
turbine and so on. In 2003, the New Energy andIndustrial Technology Development Organization(NEDO) started three demonstration projects in Aomori,
Aichi and Kyoto prefectures under its Regional Power
Grid with Renewable Energy Resources Project. Thesedemonstration projects evaluate the feasibility ofintegrating new energy sources into a local distribution
network. In addition to these demonstration projects,
several demonstration projects have been conducted by
the private sector.

2.1 Three pillars of technological actions andmeasures: avoid, shift and improve
As just described, Japan has made many efforts todevelop and promote technology for GHG emission
reduction in both the private and public sectors. These
efforts comprise three mainstays. The Kaya identity is a

useful tool for understanding GHG emission reduction
actions. The Kaya identity is a methodology forexpressing CO2 emissions by multiplying population,
activity level per capita, energy intensity and average
emission factors as shown in the following equation.
CO 2 = Population ×

Activity
EnergyCO2
××
Population Activity Energy

Eq.1

The second item on the right-hand side expresses
activity level per capita, the third item represents energy
consumption per unit activity (energy intensity), and thelast item is CO2 emissions per unit energy consumption(average emission factor). By using the Kaya identity,
the level of effort needed to achieve a certain CO2
reduction can be easily analyzed.
It is assumed that “population” will not change as aresult of taking GHG emission reduction actions. Thus,
emission reduction can be considered almost equal to
improvements in “activity/population,” “energy/activity”(energy intensity) and “CO2/energy” (average emission
factor) created by technology, as shown in Fig. 6.
Therefore, based on analysis using the Kaya identity,
technological actions can be categorized into thefollowing three categories (mainstays):
1) AVOID the use of energy services2) SHIFT energy sources to less GHG-intensive ones
3) IMPROVE energy use efficiency
Essential to avoiding the use of energy services is
cutting the amount of energy wasted. Changing lifestyles
and business-styles also contributes to avoidance of theuse of energy services. In order to accelerate actions to
avoid the use of energy services, it is also important tomonitor and visualize energy consumption.
Shifting energy sources to non-GHG-emitting energy,
such as renewable energies and nuclear power could
lead to sharp reductions of GHG emissions. Renewables
are one of the key technologies for promoting a shift.
Renewable energy capacity has steadily grown all over
the world as well as in Japan, as shown in Fig. 7. Fromthe viewpoint of energy sources, hydropower is the
120,000

Avoid activities

Improve efficiency

Shift resources

Reduce timespent foractivities

Cut energy
waste

Replace with energyefficient appliances

Install renewableenergy technologies

100,000
Capacity of Renewables [MW]Activity
EnergyCO 2
CO 2  Population 
Population Activity Energy

Marine

Wind

Solar

Bioenergy

Geothermal

80,00060,00040,00020,0000

Fig. 6 The Kaya identity and three mainstays of a reduced-carbon
energy system.

Hydropower2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Fig. 7 Installed renewable energy capacity (IRENA, 2017).

16

S. ASHINA

dominant technology among renewable resources
throughout Japan. After the year 2000, capacities ofsolar are increasing drastically due to enforcement of afeed-in-tariff (FIT) scheme.
Replacing and/or installing energy efficient technologies
have been key actions to improve energy use efficiency
heretofore. Increasing air leakage efficiency andstrengthening thermal insulation for rooms and spaces arealso effective measures to improve energy efficiency. In
general, energy efficient technology requires additionalcosts for installation. Subsidies and tax relief, however,
could accelerate actions to improve energy use efficiency.
The availability of renewables differs place-by-place.

3. Future Directions of Technology
Development toward the Paris Agreement
Japan has already undertaken development of various
kinds of technology and its implementation in society,and these activities contribute to the suppression of GHG
emissions in Japan. Figure 8 shows the CO2 emissions
trajectory from 1965 to 2016 by sector. The total CO2
emissions trend traces a similar pathway to total primaryenergy consumption as shown in Fig. 1. Before the oil
1,400

CO2 Emissions [MtCO2]

1,200
1,000
800
600
400
200
0

1965
Power

1970

1975

Ownuse1980
Industrial

1985

1990

Residen�al

1995

2000

Commercial

2005

2010

2015

Transporta�on

Fig. 8 C
 O2 emissions by sector from 1965 to 2015 (EDMC, 2017).

crises, CO2 emission increases corresponded to thegrowth of oil consumption, rising from 392.2 MtCO2 in1965 to 917.5 Mt-CO2 in 1973. After the oil crisis, total
CO2 emissions remained roughly flat at the start ofbubble economy in the latter half of the 80s, because
energy sources shifted to natural gas and nuclear power,
which emit relatively less CO2 per unit energy than oil,and energy-saving activities had become widely acceptedin the industrial sector. In the 90s, total CO2 emissions
showed a similar trend to primary energy consumption,
but in the 2000s, the growth rate of total primary energy
consumption nearly flatlined, while on the other hand,
total CO2 emissions continued to increase, except in
2009, after the global recession. The earthquake andnuclear accident of March 2011 triggered a reduction in
CO2 emissions. Although nuclear power was replaced byfossil fuels such as coal, oil and natural gas, the national
power-saving edict, issued on July 1, 2011, led to achange in attitudes among businesses and citizens toward
not only electricity consumption but also all other typesof energy consumption.
The development of innovative technologies needed
for building a low-carbon society by the deadline might
depend on the accumulation of whatever technologies
have been developed up to that time, changes in systems,
the preparation of social infrastructure that can enable
these new technologies to be incorporated and otherfactors. Table 1 summarizes major technologies forachieving sharp GHG emission reductions by 2050
based on Ashina et al., 2012. In order to achieve theParis Agreement in the long-term, various types oftechnologies in all sectors should be implemented:
energy-efficient air conditioners, LED lights, etc., in theresidential sector; energy-efficient boilers and fuelconversion in the industrial sector; hybrid automobilesand electric vehicles in the transport sector; and energyefficient fossil fuel-fired power generation, CCSequipped power generation, etc., in the energy supply
sector. In addition to these individual technologies,

Table 1 M ajor technologies useful toward achieving the Paris Agreement.
Major technologies
Residential andcommercial sector

Energy-efficient air conditioners, districtwide heating and cooling (cooling/ heating/ hot water), electric heatpump hot water heaters, fuel cell hot water heaters, solar water heaters, energy-efficient lighting, energy-efficientelectrical appliances, energy-efficient commercial power equipment, etc.

Transport sector

Electric vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, improved automobile fuelconsumption (lightweight vehicles, etc.), energy-efficient railways, energy-efficient shipping, energy-efficientaviation, biofuels, etc.

Industrial sector

Innovative steel manufacturing processes, innovative chemical manufacturing processes, increased efficiency forpaper and pulp manufacturing processes, increased efficiency for cement manufacturing processes, highperformance industrial furnaces, energy-efficient motors, energy-efficient boilers, increased efficiency for home
generators, fuel conversion, etc.

Energy supply sector

Energy-efficient coal-fired thermal power generation, energy-efficient gas thermal power generation, nuclear
power generation, general hydroelectric power generation, small and medium-scale hydroelectric power
generation, geothermal power generation, photovoltaic power generation, onshore wind power generation,
offshore wind power generation, biomass power generation, waste power generation, hydrogen production
through fossil fuel reforming, hydrogen production through electrolysis, carbon capture and storage technologies,etc.

Transitions of Energy System and Technologies in Japantechnology systems (or energy-system technology) will
also be implemented.
Among these technologies and systems, batteries,
energy management and local energy networks are
anticipated as innovative technologies for the future.
Since early times, Japan has carried out development
projects for various technologies expected to contributeto large reductions in GHG emissions in the future, suchas hydrogen fuel, fuel cells and carbon capture andstorage (CCS). Some of these technologies have diffused
as planned, but others are lagging and have yet to be
introduced to the market. We can take fuel cells, atechnology first developed by the National Aeronautics
and Space Administration (NASA) in 1961, as an
example. From 1981 to 1986, scientists in Japandeveloped the phosphoric acid fuel cell (PAFC) in the
Moonlight Project. The basic technologies were
demonstrated in the 1990s, and projects such as the New
Sunshine Project and the Fixed-type PAFC Millennium
Project of the Japan Gas Association were carried out
later (2000 to 2004) to highlight the potentials of PAFCs.
Yet, as of this writing, fuel cells have only been
introduced on a trial basis or for demonstration byelectric and gas supply companies. Today, nearly 50
years after its conception, the fuel cell is yet to be solidly
positioned in the market. The status of CCS, the nuclear
fuel cycle and nuclear power technologies is similar, but
technology systems have much room for R&D.

a) Innovative Battery Technologies
Renewables are expected to play a central role in
low-carbon electricity supply systems. Photovoltaic
systems (PVs) and wind power generators have now
been widely adopted around the world as an option for
reducing CO2 emissions, but electricity from renewables,
especially solar and wind, has large volatility over time.
Renewable electricity supplies vary according to natural
conditions, such as solar insolation and wind speed, andthe electricity supply from them rarely matches
electricity demand. Thus it is important to level theelectricity outputs of renewables to match supply-anddemand.
The batteries developed at present can be classified
into six types: (1) secondary batteries, (2) capacitors, (3)fly wheels, (4) superconducting magnetic energy storage(SMES), (5) pumped hydro, and (6) compressed airelectricity storage. Among these types, secondary batteries
can be expected to become popular in future society.
b) Energy Monitoring Systems in Conjunction with
Energy Management
To accelerate lifestyle and workstyle changes, it isimportant to share with all stakeholders information
about the effects of energy saving actions and behavioral
changes on reducing energy consumption for a lowcarbon lifestyle. Japan already has its own statisticalsystem for energy supply and demand, but statistical data
are mostly capable of describing the national orprefectural situation, and it is difficult to determine the17

effects of avoidance actions such as lifestyle changes by
each household. On the other hand, a monitoring system
could provide a comprehensive picture on how muchenergy is consumed and for what purposes in houses,
buildings and districts, but efforts to address national
and/or prefectural energy consumption would face manydifficulties if they only relied on a monitoring system.
Many companies and research institutions have started
developing energy monitoring systems, and some havealready been implemented in the real world. The
government of Japan also supports R&D of energy
monitoring systems in conjunction with energy
management systems. Kitakyushu launched a project
named “Kitakyushu Smart Community Creation Project”
from FY2010 to FY2014, and as a part of the project,smart meters and displays for electricity consumption
were installed in houses and offices. Based on the
project’s results, installing energy monitoring system
could reduce 0.6% of energy use in offices, andintroduction of energy management systems and batteries
in households could almost halve their energy
consumption (Sasakura, 2015).
Energy monitoring systems usually consist of a seriesof data collection systems involving energy-use monitors
for residential, commercial and industrial use; transportmonitoring; greenhouse gas inventories; land use maps;
demographic assessments; and so on. Figure 9 gives theschematics of an energy monitoring system as an
example. The system comprises four functions: (1)electricity monitoring, (2) data transference, (3) datacollection and (4) data sharing. Electricity monitoringmeasures real-time electricity consumption by using
sensors installed in the distribution board of eachbuilding. Electricity consumption can be monitored
minute by minute, and the amount of electricity
consumed can be determined by multiplying power
current by power voltage.
The monitored data are transferred to a data serverusing the data transfer system. The system uses two
types of data transfer methodology. One system uses awired or wireless Internet connection and the other uses
a mobile line. The system is expected to be installed in
offices and commercial buildings which have wired-/
wireless-Internet connections as well as houses whereinternet connections are not always available. The datatransfer speed of mobile lines is slow compared toInternet connections in general, but mobile lines are now
very common everywhere in Japan, so the system
includes both mobile lines and Internet. Mobile lines
often fail to transfer data due to poor reception or slow
connections. To avoid loss of monitored data, the datatransfer system includes temporary data storage that canhold data for 10 days.
The transferred monitoring data are stored at a dataserver. The server has the function of sharing data via
the Internet. Stakeholders such as residents, workers andstaff at monitoring sites can use a browser to accessmonitoring data. The system provides graphicalinformation systems to users for getting information

18

S. ASHINA(2) Data transfer

Internet(3) Data collecting

Monitored
data

Mobile line

Data server
Assembled data

Monitored data

(1) Electricity monitoring(4) Data sharing

Web browser

Distribution
board

Public signage

Currency andvoltage sensors

Fig. 9 Schematics of one case of an energy monitoring system (Ashina et al., 2016).
Lighting

Receptacle

Other

AC

Refrigerator

Sun
3/6

Mon
3/7

Tue
3/8

Wed
3/9

Thu
3/10

Fri
3/11

Sat
3/12

Sun
3/6

Mon
3/7

Tue
3/8

Wed
3/9

Thu
3/10

Fri
3/11

Sat
3/12

Sun
3/6

Mon
3/7

Tue
3/8

Wed
3/9

Thu
3/10

Fri
3/11

Sat
3/12

Sun
3/6

Mon
3/7

Tue
3/8

Wed
3/9

Thu
3/10

Fri
3/11

Sat
3/12

Sun
3/6

Mon
3/7

Tue
3/8

Wed
3/9

Thu
3/10

Fri
3/11

Sat
3/12

OfficeShopping
Mall

Cafe

Hotel

House
hold

Fig. 10 Example of monitoring data (Ashina, 2017).

both in real-time and on past electricity consumption.
The system also provides summarized information onelectricity consumption in certain areas (such as cities
and blocks), and shows information on real-timeelectricity consumption over a public signage system.
Figure 10 shows monitoring data from selected sites
on March 6 to 12, 2016. The monitoring data clearlyshow large differences among the monitored sites.
Offices and commercial facilities (a shopping mall andcafe) consume electricity mainly during the daytime,
while hotels consume electricity both day and night.
Electricity consumption in houses is low compared to
offices and commercial buildings, and is affected byfamily structure, lifestyle and travel. In other words, thelevel of electricity consumption is defined mainly by the
number of members staying in the house.
The monitoring data could be used not only for
notifying stakeholders of energy use but also formanaging energy. The Community Energy Management
System (CEMS) is a system for energy management inareas and communities, and is analogous to the Building
Energy Management System (BEMS), Home Energy
Management System (HEMS) and Factory Energy
Management System (FEMS). CEMS could manage theenergy balance between supply and demand, leading toefficient use of energy. The evolving capabilities of
EMS offer not only effective use of energy in houses
and buildings but also new opportunities to automate
some parts of the commissioning process, and cangenerate benefits over the entire lifetime of a building.
Developing a detailed systematic automated approach
will improve the quality assurance process and may evenintegrate energy audit capabilities that could improve theoverall performance of buildings as well.

Transitions of Energy System and Technologies in Japanc) Local Energy Networks
Local authorities have played an important role inpreventing deterioration of the natural environment andcombating environmental pollution, and they are often
more pioneering than the national government. Chapter
28 of Agenda 21 points out the importance of local
authorities in addressing global warming issues. In
Japan’s general policy for promoting measures against
global warming, basic policy concepts include theimportance of promoting collaborative action among thegovernment, local authorities, businesses and citizens;and local authorities play a crucial role in tacklingclimate change in Japan. Local authorities are expected
to set goals and directions for regional actions, promote
institutional arrangements and development of social
infrastructure for achieving a low-carbon society, andshare information among residents and businesses,
according to local natural and economic conditions.
Each prefecture has established its own plan toprevent global warming. In each plan, a CO2 reduction
target is set for 2020 and/or 2030, and concrete policies
and measures to achieve the target are revealed.
Examples of these policies and measures include
acquiring ISO 14001, an environmental management
system, to reduce the environmental impacts fromcarrying out needed business; or introducing their own
environmental management system. Moreover, in orderto promote voluntary actions against global warming byresidents, some regions have enacted their own
environmental management standards.
In general, GHG emission reduction actions by local
authorities focus mainly on energy demand-side sectors,
including the industrial sector, residential andcommercial sector, and transportation sector, although
the largest GHG emitter in Japan is the power sector, asupply-side sector. Given this situation with the energy
end-use sectors, it can be pointed out that in order toreduce GHG emissions at the local scale, it will be
important to accelerate diffusion of energy-efficienttechnologies among the energy demand-side sectors aswell as to construct a low-carbon energy supply system
within each region.
Progress in designing and implementing local energy
systems involves many difficulties. For example, eachregion has different issues that need to be resolved. The
town of Shinchi, which is located in the northern part of
Fukushima Prefecture and has a population of 8,000, wasselected as an “environmental future city” by the Cabinet
Office in 2012. In Shinchi, a gradual population decline
after 2005 led to a reduced labor force in both primaryindustry and the construction industry, and lower
industrial output. The tertiary industry labor force
continued to grow until 2015, but has started to decrease
now. These shrinking and aging population issues arecommon among rural areas in Japan, and efforts toimplement local energy systems in such areas should aim
to reduce GHG emissions and to solve the problem of
decreasing population. Another difficulty is the19availability of energy sources. Energy systems differ fromregion to region, and the availability of technology also
differs. The northern part of Japan relies heavily on
kerosene heaters and hot water supply equipment, while
the southern regions rely on hot water supply equipmentusing town gas and/or electricity. Implementing gas-basedenergy systems in the northern area could decrease GHG
emissions but would need investment and new
construction of gas infrastructure. For areas rich withresources in renewables such as solar, wind andgeothermal, installation of renewables is a key action for
low-carbonization of the area, while for areas locatedclose to industrial complexes, utilization of waste heatwould be a possible option. Although improvement ofenergy efficiency will be the key to low-carbonization in
all regions, it is important to formulate plans and actions
for a low-carbon society based on regional characteristics.
Some cities in Japan have launched new challenges forachieving energy transition. Shinchi, again, in northern
Fukushima Prefecture revised its city development plan
after the Fukushima accident. Figure 11 gives an outlineof Shinchi’s future development plan. The city has LNG
tanks and industrial parks, and it recently started a new
town development around Shinchi Station. Using theseresources, the city is trying to shift from traditional city
development sustained by oil and fossil-fueled electricity
to an innovative development plan sustained by natural
gas and renewable energies.

4. Summary
Even before the Kyoto Protocol, Japan wasorganizing various kinds of technological development
in both the public and private sectors, and in addition to
reducing GHG emissions, these technologies havecontributed to energy saving and diversification ofenergy sources after the oil shock. Even so, continuous
technology development will be needed for achieving
the Paris Agreement.
For example, Fujino et al. (2008) notes that in order toachieve a 70% reduction in Japan’s CO2 emissions by
2050, the coefficient of performance (COP) for household
air conditioners should be improved to COP8 on a stockbasis. In 2007, the COP for household air conditioners on
a stock basis was 4.26 for heating and 3.85 for cooling(EDMC, 2017), so technological advances able to double
these figures will be needed in order to achieve therequired performance by 2050. Such technologicalinnovation and market penetration processes will require
public and/or private funding for R&D as well as
consumers’ (including companies’ and businesses’)support through the market.
Obviously, some technologies could be deployed
immediately, such as a fuel shift to imported biofuels
and co-firing of woody biomass in coal-fired plants. In
most cases, however, dissemination would require fromseveral years to several decades. Even if innovativetechnology is successfully launched in the market withthe support of R&D investments and/or policies, if

20

S. ASHINATo Natori

Newly locatedindustries
New town
around stationｘ
Komagamine

Plant
factories

Mega solar

Plant
factories

Energymanagement

LNG base

Newly locatedindustries

LNG power plant
Food industries

Soma city

Data center

Heating
Cooling
Gas(LNG)
Electricity

Fig. 11 Innovative development of Shinchi Town (Based on Fujita and Hirano, 2016).

consumers do not choose them when they appear on themarket, subsequent technological innovations will
become less certain to be carried out and further
innovative technologies will be prevented fromappearing on the market, e.g., fuel cells, electric vehicles
and solar heaters.
Technology is a key element of efforts toward a lowcarbon society, but technologies and R&D alone cannot
attain it. Realizing GHG emission reduction with only
technological countermeasures would be costly, but a
combination of policies and countermeasures, such as
lifestyle changes, good institutional arrangements andreassembling the transportation system, would lower thecosts. Taking early action could lead to cost-effective
ways to achieve emission reductions. For that, a large
investment is needed in the initial stage, but it is likelythat early market entry of technologies will lead to
reduced costs of future technologies due to the“learning-by-doing” effect, and the additional
investments will be balanced by the sum of reduced
technology and fuel costs. Learning-by-doing effects canbe detected for many commodities and technologies
when observing markets. Rubin et al. (2015) presented aliterature review on learning-by-doing effects (or the“learning curve”) for electricity supply technologies,
including renewables. Based on their research, thelearning rate of solar PV is in the range of 10%－47%,
and that of offshore wind, 5%－19%.
Moreover, infrastructure cannot be built immediately,
making it difficult to switch suddenly to a low-carbon
type just before 2050. In addition, planning of GHG
reduction policies and actions with both technology andnon-technology options is a key action, and it is also
important to implement and monitor the policies andactions. Planning, implementation and monitoring basedon the PDCA (Plan‐ Do‐ Check‐ Act) cycle should beestablished, so the continuous running of the PDCA
cycle can open the door to the low-carbon society, inwhich society achieves immense reductions of GHG
emissions while maintaining quality of life.
The development of a low-carbon society in Japan is
crucial for tackling climate change issues. The impactsof climate change affect everyone around the world, andJapan is no exception. Policies and actions that do notcontribute to low-carbonization will bring benefits in the
short term, but result in damage to the environment,
nature, economy and life in the long run. In addition,
considering that the global trend is toward achieving a
low-carbon society, a country may lose an opportunity
for green growth and its future international
competitiveness in low-carbon technologies if it fails to
shift to a low-carbon approach because other nations
will achieve green growth and export low-carbon
technologies and experience first.
Low-carbonization of the energy system is a key to
GHG emission reduction as well as achieving a lowcarbon society globally. Development of innovativetechnologies is also a necessary part of building a lowcarbon society, and to meet deadlines it may benecessary to accumulate whatever technologies havebeen developed up to that time, change systems, preparea social infrastructure that will enable these newtechnologies to be incorporated, and take othermeasures. Japan’s experience and expertise intechnological R&D could go a long way toward taking
the first step in the right direction. It will provide afoundation for sharp GHG emission reductions andestablishment of a low-carbon society not only in Japanbut also all over the world.

Transitions of Energy System and Technologies in Japan

21

Acknowledgements
This study was conducted through a grant from theEnvironment Research & Technology Development
Fund (2-1402, 2-1411 and 2-1711) and the Project toAdvance MRV and Related Techniques in Indonesia for
the Promotion of a Joint Credit Mechanism (from
FY2014－2017) operated by the Ministry of theEnvironment, Japan. The authors would like to express
their appreciation for the assistance and cooperation
provided by all who helped to make this study possible.

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Shuichi ASHINA
Shuichi Ashina is a senior researcher in the Transboundary Impacts & Mitigation Modeling Section
at the Center for Social and Environmental Systems
Research, and manager of the International
Coordination Office in the Planning Department at
the National Institute for Environmental Studies.
His research focuses on the field of energyeconomy-environmental systems modeling and its application to the designingof low-carbon societies from cities/municipalities to Japan and Asian countries.
He received his B.S., M.S. and Ph.D. degrees in Mechanical and System
Engineering from Tohoku University.
(Received 14 June 2017, Accepted 7 September 2017)