Technology to Support Low-Carbon Society (Using Energy)

  • Hiroshi Komiyama
  • Koichi Yamada
Open Access
Part of the Science for Sustainable Societies book series (SFSS)


Against the backdrop of environmental regulations and oil shocks, Japan has been refining its energy-saving technologies. There are many top world-ranking energy-saving products, and we frequently hear people saying that further improvement of energy efficiency is difficult. In reality, however, there are hardly any products for which energy efficiency has already reached the limit of improvement.

It is possible to theoretically derive a target value for how far energy efficiency can be enhanced. Appropriate target setting produces new innovations. Innovative technologies lead to the realization of a low-carbon society, and at the same time, they can be a trump card for new growth strategies. How can we improve efficiency and maximize the value per energy input? We still have a long way to go in overcoming these issues.

We discuss here the direction of energy efficiency improvement and low carbonization of sectors such as transport, household and metal production.

3.1 Direction of Improvement in Energy Efficiency

3.1.1 “Daily Living” and “Monozukuri”

In a low-carbon society, we aim to suppress the use of energy that leads to CO2 emissions. It is not a story about having to endure anything. As shown in Fig. 6, Japan succeeded in decoupling twice in history. A low carbon society is a concept that can coexist with economic growth and affluent life styles.

CO2 emissions can be roughly divided into “daily living” and “manufacturing.” Everyday life consists of three elements, “Transportation,” “Business,” and “Home.” Manufacturing is “industry” itself.

Of the various fields, since transportation can be left alone and low-carbonization will still progress because automobile manufacturers are enthusiastic about improving fuel economy and developing eco-cars. Toyota launched a vision to reduce CO2 emissions of new cars sold in 2050 by 90%. In addition, as new forms of services such as car sharing have emerged, a lifestyle without cars that has especially spread among young people in the city will also be a driving force for low carbonization.

Trends are similar in business and household energy consumption, and household electrical appliances such as lighting, air conditioning, hot water supply, kitchen each account for one-third. Initiatives to reduce energy consumption include replacement with high-efficiency products and introducing double-glazing windows with high thermal insulation effect. Although such updating of facilities is smoothest at the time of rebuilding, the rebuilding of houses is once every 40–50 years, and office buildings are once every several decades. Therefore, in order to achieve the vision in 2050, it is necessary to rationally promote renovation of existing buildings. For that purpose, we should establish a system like “paying electric bills as is” described later. For users, the big initial investment is the biggest factor of their hesitation about renovation. If organizations and groups such as funds that promote low carbonization shoulder the initial investment and users can direct the electricity bill they saved from equipment renewal toward repayment, it would become easier for them to undertake renovations.

Meanwhile, in the case of monozukuri, the majority of energy consumption goes toward manufacturing materials. The industry with the largest energy consumption is the steel industry, followed by such industries as the chemical and ceramic, stone, and clay (cement) industries. When thinking about low carbonization of the manufacturing sector, it must not be forgotten that man-made objects such as iron and cement will eventually become saturated.

All man-made objects, whether it be an automobile or a building, are continuously introduced into the city, accumulated, and eventually become saturated. From now on, in order to build a new building in Tokyo, we have to destroy the existing building. That is, existing man-made objects are always discarded when newly introducing man-made objects. Recycling this waste is more energy efficient than digging and processing new natural resources. In the sense that waste from the city becomes a resource of new man-made objects, it is called an urban mine. It is also a word that has drawn attention in connection with rare metals, etc. in mobile phones. Monozukuri depends on whether it is possible to build a highly efficient material circulation system premised on the saturation of man-made objects and utilization of urban mines.

In this way, energy conservation that reduces energy consumption in individual sectors and expanding the use of renewable energy are two pillars for realizing a low-carbon society.

The IEA predicts that renewable energy will rank at the top of power generation by power source along with coal in 2030 and further increase in the future, with 60% of the investment in power directed at renewable energy by 2040. Meanwhile, 60% of investment in power in 2015 has already been directed at renewable energy, and this ratio reached 70% in 2016. Taking this into consideration, it should be all right to think that the introduction of renewable energy will probably progress at a faster pace than predicted by the IEA.

In this chapter, from the above viewpoint, we will consider technologies that support low carbonization.

3.2 Low Carbon Technologies in the Transportation Sector

3.2.1 Shipment Does Not Consume Energy?

Gasoline and electricity are necessary to move a car. Even when you ride a bicycle, you need a reasonable leg strength. Therefore, you tend to believe that energy is always consumed when you move something, but that is not accurate.

Actually, the theoretical limit of horizontal transportation energy is zero.

Imagine speed skating. When a skater starts skating on a skating rink, he/she kicks his/her skates powerfully with his/her legs. In order to generate kinetic energy, “work” is necessary, and a lot of energy is used here. However, when the speed becomes higher than a certain level, energy is theoretically not needed. The skater who reaches the goal is smoothly circling the rink while not kicking with his/her foot.

The skater will eventually stop by being caught by his/her coach, or grabbing the wall by himself/herself. At this time, kinetic energy turns into heat and is released into the atmosphere. The energy lost is equal to the energy used in starting to skate. Therefore, if you can store energy generated at the time of stoppage and use it at the start, you can continue to exercise forever.

A regenerative brake mounted on a hybrid vehicle (HV), etc. is exactly the application of this principle. The energy released when decelerating by applying the brake is saved in the battery and is utilized when starting and accelerating.

In the case of vertical motion as well as horizontal transport, the theoretical limit is zero. Pull the wire of the elevator on a pulley and attach a weight of the same weight to the other side of the elevator. If a good bearing is attached to the pulley, and without friction, no energy is needed to move the elevator up and down.

That is, friction is the cause of the energy consumed in transportation. A skater can continue skating by inertia after reaching a certain speed because the friction is small. Likewise, a satellite continues to fly and the Earth keeps going around the Sun because the friction is zero in outer space. However, there is friction in the real world. The bicycle stops unless the rider keeps rowing, and the skater cannot slide forever.

How can we reduce friction losses? This is the key to energy efficiency in transportation.

3.2.2 Energy-Efficient Cars Appear One after Another

Let’s think about the energy efficiency of automobiles powered by gasoline engines that account for the majority of cars in the domestic market now.

A gasoline engine car burns gasoline in a cylinder, imparts a force to the cylinder head, rotates the shaft with that force, adjusts the direction and speed with many gears, etc., rotates the wheel, and runs. The overall picture is that the chemical energy of gasoline is converted to the work of a cylinder head, and that work is used to transport the car.

The chemical energy of gasoline is converted into work and heat. Since the law of conservation of applies here, chemical energy is converted by 100% if heat and work are combined. In theory, all gasoline may be converted to work, but only about 35% becomes work, and the remaining 65% is wastefully consumed as heat. Energy is thrown away in heat in various places, such as heat radiation from the exhaust gas and the engine, friction between the tires and the ground, and friction inside the car such as gears and transmissions.

Especially, when starting and accelerating, it requires a large amount of work, so a lot of frictional heat is generated and a considerable amount is released into the atmosphere. After reaching a certain speed, no energy is theoretically necessary, while running at a constant speed, but in fact energy is consumed due to friction between the tires and the ground, and so on. If traveling at high speed, air resistance also occurs. Depressing the brakes during deceleration or stopping is friction itself, and even when stopping at an intersection, the engine is moving, and energy is used here as well.

Therefore, improving the following five points is a guideline for energy conservation in automobiles.
  1. 1.

    The efficiency of conversion from chemical energy to work is not 100%.

  2. 2.

    Friction of gears, etc. accompanying the transmission of force from the engine to the tires.

  3. 3.

    Friction between the tires and the ground.

  4. 4.

    Friction between the car body and air.

  5. 5.

    Friction due to braking.


One specific approach to improving efficiency is hybridization.

At the end of the 1990s when I proposed Vision 2050, Toyota’s hybrid car “Prius” was the topic of conversation (Fig. 3.1). The Prius debuted in 1997 when the Third Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 3) was held in Kyoto. The fuel consumption of the first model indicated on the car catalogue was 28 km/l (10–15 mode). At that time, the car of the same car class had fuel efficiency of less than 20 km/l, so it became a hot topic, as its fuel efficiency was outstanding.
Fig. 3.1

Latest model of Toyota Prius

The HV is a system that uses energy efficiently. It operates with an electric motor in normal cruising from vehicle start up to the mid-speed range. During deceleration and braking, it converts vehicle braking energy into a source of electric power. The engine stops not only when stopping at an intersection, etc. but also while driving, when the engine does not have to operate. In other words, it solves the problem of (1) conversion from gasoline to work and (5) friction due to braking.

Generally, HV is said to be suitable for urban areas because there are many signals, cars have to stop and go frequently, and there are many cases of starting with regenerative energy and electric power without operating the engine. When there is little regeneration during a long-distance drive, it consumes fuel just like a normal gasoline car.

Also, as the plug-in hybrid car (PHV) has a larger battery than the HV, it can be recharged not only by regenerative energy but also from an external power source. Therefore, it can run for several tens of kilometers without gasoline like electric vehicles (EV).

3.2.3 Car Energy Efficiency Increases Eightfold

How far can a car increase energy efficiency? Until a while ago, there were two choices, gasoline or diesel, but now a variety of cars are running on the market. EVs without engine are thought to be only light cars or compact cars, but recently, sedan type EVs or sports type EVs have appeared.

Fuel cell vehicles (FCV) have also become available on the market (Figs. 3.2 and 3.3). A FCV carries a fuel cell (FC) stack instead of an engine. The mechanism of FC was discovered in the early nineteenth century, and its history is old. For application to automobiles, it was a challenge to install gaseous hydrogen at room temperature on cars, but a 70 megapascal high-pressure hydrogen tank using carbon fiber reinforced plastic was successfully commercialized. A FCV generates electricity through the reaction of hydrogen and oxygen in the air, and is propelled by that energy. CO2 emissions during driving are zero as in the case of EVs, but a FCV has more power than an EV, better driving performance, and longer cruising range.
Fig. 3.2

Toyota FCV “Mirai”

Fig. 3.3

Honda FCV “Clarity Fuel Cell”

Figure 3.4 plots a commercial model with fuel consumption on the vertical axis and vehicle body weight on the horizontal axis. It is worth noting that in Japan, we use the mileage per 1 l of fuel to represent fuel economy, but in this figure, the Western style of fuel consumption per kilometer is used. That is, since the vertical axis is the fuel consumption per unit distance, if the same weight is compared, the larger the value of the vertical axis, the worse the fuel consumption.
Fig. 3.4

Structuring of Knowledge: Energy efficiency of automobiles increases to 2 × 4 = 8 times. (Created by the Author. Source: carview!)

When other conditions are constant, fuel consumption and body weight are proportional. Therefore, the data of each model is plotted in general on a straight line, and the fuel consumption amount approaches zero as the weight of the vehicle body gets lighter. In theory, a car can move without consuming energy if the body weight is zero.

Indeed, energy-saving races are held all over the world. Drivers compete on how much they can reduce fuel consumption, or how far they can travel on 1 l of gasoline. A few years ago, Guinness record was set by a driver traveling more than 5000 km on 1 l of fuel. At that time, the weight of the car was only 25 kg. Even with the driver’s weight of 45 kg combined, the load was 70 kg.

Since commercial vehicles must also provide safety and comfort, it will be difficult to reduce weight this far, but considering efficiency, it goes without saying that the lighter the car body, the better. Besides downsizing the car body, using light materials is a weight reduction method. In super cars and luxury cars, materials effective for weight reduction of the car body while maintaining a certain degree of robustness are being actively used, such as aluminum, carbon fiber reinforced plastic, and high-tensile steel, which is an alloy of iron.

Well, let’s return to Fig. 3.4. Comparing the fuel consumption of all cars in 1999 with that of cars in 2016, the current consumption is 33% less for the same weight. This is an energy-saving effect due to progress in driving power technology over the past 17 years. As the weight of cars of the same size is becoming lighter through further weight reduction, it is considered that the fuel consumption of the same type of cars has been reduced by about 40%.

While the fuel consumption of HVs is less than half of that of 1999 gasoline engine cars, that of EVs and FCVs are even half of that of HVs. In other words, the energy efficiency of HVs is twice as high and that of EVs and FCVs is four times as high as that of gasoline engine vehicles.

In the future, with technological innovation, the car body weight can be made lighter. If we can reduce the weight of a car by half, energy efficiency will be doubled so we can make EVs and FCVs eight times more efficient.

In the discussion on energy, it is important as to what electricity and hydrogen are made from. Here, I want to note that electricity is calculated based on Japan’s standard power supply configuration, and for hydrogen as well, it is calculated based on the value derived when water is subject to electrolysis under the standard power supply configuration.

3.2.4 A Rich Car Life with Diverse Eco Cars

Prius has carried out three full model changes so far, and each time, Toyota has developed a new hybrid system to optimize energy efficiency. Hybrid technology has been polished over the past two decades, and I think that citizens’ understanding of HV has deepened.

Initially at the time of release, the Prius had a higher car body price compared with the same-class cars, and there were also opinions questioning, “Are you really getting it?” Recently, however, discussions on simple loss and gain hid behind the scenes. Certainly, the initial cost may be high, but if used appropriately, fuel consumption can be suppressed, and in the long run, it is economically advantageous. Less fuel consumption means less environmental impact. It can be said that there are more consumers who are making wise choices in terms of comprehensive satisfaction rather than because these cars are becoming cheaper.

Not only can EVs and FCVs that do not have an engine contribute to a low-carbon society but also they present no concerns about noise and exhaust gases that were associated with engine vehicles, so they are friendly to passengers and people outside the car. In addition, they are compatible with new technologies such as a driving support system including automatic braking and automatic driving systems because they are electrical drive vehicles, and therefore, they can be driven safely and comfortably.

Since a variety of models are coming out, it is fun to be able to choose according to lifestyle. Some owners are saying, “An EV is sufficient because I mainly use if for shopping in the neighborhood.” Still others are saying, “Sometimes I go on long drives, so a PHV is better.”

In rural cities, cars are the main means of transportation. Because cars are indispensable even for commuting and a bit of shopping, the trend has been toward one person owning one car, but it is a waste that only one driver is on board a minivan or sedan. Recently, the development of one-seater EVs called city commuters or personal mobility has been proceeding (Fig. 3.5). Because they are compact and the specs are suppressed, the price is also cheaper compared to EVs in general. Smart ways of using these vehicles will become possible: small EVs for everyday short distance travel and PHVs for going out on a drive with family and friends.
Fig. 3.5

“P·COM,” a COMS personal mobility vehicle manufactured by Toyota Auto Body

Or, it may not be surprising to see people who possess ordinary cars and small EVs like those who have separate uses for cars and motorcycles. Even if you own more than one, you cannot move at the same time. As mentioned above, the energy efficiency of individual cars improves, so you can enjoy the pleasure of riding various cars without imposing environmental burden. With regard to long-distance-drive cars that are not used frequently, it is also a wise choice to use them for car sharing or car rental.

Sharing business has spread to various fields as a result of the progress of IT. Ideas such as sharing personal mobility in the area and lending it to tourists have also emerged, and from the viewpoint of regional revitalization, the evolution of cars is receiving a lot of attention.

In order to promote the low carbonization of the transportation sector as a whole, it is important to increase the energy efficiency of each car, and at the same time, to utilize it at the right place according to the characteristics of each car. The emergence of a variety of mobility has brought about the joy of making choices, and new business opportunities are being created. CO2 emission reduction and affluence are concepts that can fully coexist.

3.2.5 Modal Shift in Movement

Private passenger cars account for 47.5% of CO2 emissions in the transportation sector. This is followed by cargo vehicles and public transportation (buses, taxis, railways, ships, and airlines), which respectively account for 35.1% and 17.4% of the CO2 emissions (Fig. 3.6). Therefore, in order to realize a low-carbon society, it is necessary to promote reduction of CO2 emissions by cargo vehicles.
Fig. 3.6

Breakdown of CO2 emissions in the transportation sector. (Source: Ministry of Land, Infrastructure, Transport, and Tourism.

A cargo vehicle refers to a truck, and there are commercial cargo vehicles used by shipping companies and a private cargo vehicles owned by non-transport operators such as farmers or shops. When comparing the CO2 emissions per ton-kilometer, which is the product of the transport weight (tons) multiplied by the transport distance (kilometers), as shown in Fig. 3.7, private cargo vehicles emit about six times more CO2 than commercial cargo vehicles. Furthermore, the commercial cargo vehicles emit more than five times as much CO2 as ships and eight times as much CO2 as railways. Since the amount of CO2 emissions is smaller with ships than with cargo vehicles, and smaller with railways than with ships, switching from truck transport to ships or railways can contribute to reducing environmental impact.
Fig. 3.7

Amount of CO2 emissions per transport volume (cargo). (Source: Ministry of Land, Infrastructure, Transport, and Tourism)

Changing the means of transportation in this way is called a modal shift. The Ministry of Land, Infrastructure, and Transport has promoted a modal shift for more than 10 years, but it has not progressed sufficiently. The reason is that truck transport is convenient. You can go anywhere at any time on a truck, and you can deliver in small quantities. On the other hand, ships and railways have low degree of freedom in operation routes and time schedules, and when picking up cargoes and delivering them to their final destinations, trucks are eventually used in combination. If the shift is not done on a reasonable scale, cost benefits are hard to come by.

However, the logistics industry is currently faced with the big problem of shortage of truck drivers. The aging of drivers is progressing, but there are no young volunteers because of the severe labor environment such as long working hours and low wages. Even if salaries and conditions are slightly improved, there are reportedly no responses to job advertisements. On the contrary, the number of logistics/home delivery is increasing due to such developments as the rise of online shopping. If the load per driver increases, it is clear that the risk of delays in delivery and traffic accidents will increase, but in the long term there is no prospect of resolving the shortage of manpower. The logistics industry is now being forced to build a new business model.

Modal shift can contribute to solving such problems in the logistics industry. If you replace a truck with the railway, you will not have to secure a driver for that section. If companies dealing in small-lot delivery work together well, it is possible to secure the benefits of scale that can be felt using railways and ships such as increasing the loading efficiency of containers and securing cargo on the return trip.

A technology that has emerged that can compensate for shortage of human resources is automatic driving. Isuzu Motors and Hino Motors announced that they will jointly develop truck and bus automatic driving systems. They are aiming at convoy driving consisting of three or more trucks. During the experiment, a driver will ride on each of the vehicles, but finally, there will be a driver only on the leading vehicle, and the following vehicles are planned to be unmanned. The vehicles are not physically connected, but the idea is like that of a one-manned train. This makes it possible to increase transportation efficiency while reducing personnel expenses.

In addition, if complete automatic operation is realized in the future, the driver will be released from the obligation to monitor the forward direction, so it will be possible for the driver to engage in processing vouchers, sales activities, product planning, etc. inside the vehicle. Speaking of truck drivers, it is said to be a typical example of physical work, but it may be transformed into creative work as a result of progress in technology.

3.3 Low Carbon Technologies in the Home and Business Sectors

3.3.1 Promotion of Energy Saving Is Economically Advantageous

Where is energy consumed in the household sector? Figure 3.8 shows the percentage of energy consumption by usage in the household. The largest proportion is power, lighting and others, followed by hot water supply and heating. Power means energy consumption by electric appliances such as refrigerators. There is no big difference in this ratio even in the office, so with regard to low carbonization in the home and business sectors, the key is how much consumption can be reduced in these large energy consumption sectors.
Fig. 3.8

Changes in unit energy consumption intensity per household and energy consumption by use. (Source: Energy White Paper 2017)

For example, refrigerators and air conditioners will be replaced with the latest models with high efficiency, and lighting will be replaced with high efficiency LED bulbs. With regard to hot water supply, energy waste is reduced by simultaneously obtaining hot water and electricity through the use of home fuel cell energy farms and the heat pump electric water heater EcoCute. If heat insulation is installed firmly on the walls and floors and double glazing with excellent heat insulation performance is installed for the windows, the heating and cooling efficiency of houses and buildings will be improved. By doing all that we can do in this way and expecting future technological innovation, we can reduce the current home energy consumption by a quarter in 2030. Then, if the remaining quarter of the energy can be covered by power generation by solar cells, etc., the energy brought in from the outside would be zero. If the amount of electricity generated exceeds consumption, it is also possible to sell energy.

If we list energy saving measures such as these, some people say, “Energy conservation cannot be done because it costs money.” However, it does not mean that we have to do everything right now.

Even if you use electric appliances such as air conditioners and refrigerators quite normally, they will be replaced every 10 years. It is impossible that newly purchased products are less energy efficient than the models 10 years ago. Low carbonization is possible by simply replacing the older models.

Energy efficiency is also improved in recent models of Enefarm and EcoCute. Besides, as the prices have dropped considerably since their launch, it should be easy to recognize the cost benefits of introduction. Insulation materials and double-glazing windows are somewhat difficult to incorporate into existing houses, and the costs are relatively high. However, the energy saving effect of heat insulation is great. In case of new construction or large-scale renovation, installation should be considered positively (Fig. 3.9).
Fig. 3.9

Changes in consumption by energy sources in the household sector. (Source: Energy White Paper 2017)

3.3.2 Energy Conservation Will Be a Business Opportunity

Investments in energy saving are recoverable. If energy consumption decreases, payment of electricity charges and gas fees will be reduced as a matter of course. If energy consumption is reduced to one-quarter, the amount of pay-per-use excluding basic charges will also be one-quarter. Even if the electricity fee rises and doubles in the future, it will cost only one-half of the current price. From a long-term perspective, it will be profitable to promote energy conservation.

This means that there is a business opportunity in promoting energy conservation.

The Center for Low Carbon Society Strategy (LCS) and The University of Tokyo have jointly proposed a mechanism of “paying electricity as is.” This is a mechanism to ease the burden of households in introducing measures for reducing carbon emissions, aimed at making the energy saving/renewable energy of households significantly progress without relying on subsidies.

For example, when installing solar power generation systems and household fuel cells, financial institutions will finance initial costs and electricity fees saved by their introduction will be used for repayment. As a result, the initial investment borne by the household will be zero. As monthly payments will not increase unlike monthly installments, equipment for low carbonization can be introduced even in homes that lack sufficient funds. It is advantageous for society as a whole to be able to promote low carbonization measures without subsidizing it.

However, someone needs to take over the initial cost. In the UK, a non-profit enterprise was established and investments are made mainly by the UK Ministry of Energy and Climate Change. In Japan, cases of solar power generation promotion by a subsidiary of Osaka Gas are well known, but since credit screening takes time, it is not suitable for small scale projects. If households are being targeted, it is still appropriate to establish a fund. In addition, detailed adjustments are necessary to produce truly fruitful measures. The results of verification tests conducted at five places such as Nagaizumi-cho in Shizuoka Prefecture and Shimokawa-cho in Hokkaido from 2015 are awaited.

Meanwhile, the ESCO (Energy Service Company) project is already established as a business. The trustee of the ESCO project offers consultations on low carbon measures for office buildings, provides comprehensive services, and obtains compensation from the water utility cost that could be reduced. After the contract period has ended, the amount of reduction will be the profit that the consignor will be making.

When there are major events affecting the economy, such as the collapse of Lehman Brothers and the Great East Japan Earthquake, investment tends to be narrowed down, but investment in energy saving can certainly be recovered later. It is hoped that investors such as pension management organizations that ought to firmly recover their investments will become aware of this quickly.

3.3.3 Household Energy Consumption Is Consolidated into Electricity

Looking at energy consumption in the household sector by energy source, coal accounted for the largest proportion in 1965, followed by electricity, kerosene, and gas. In the 1970s, the proportion of coal used for heating, boiling, and cooking sharply decreased as lifestyles became modernized. In place of that, the ratio of kerosene increased significantly. The proportion of electricity and gas also increased.

In 2014, the proportion of kerosene decreased, and electricity came to account for the majority. The means to get warm has changed significantly from stoves that directly burn coal and oil to heating appliances that use electricity such as hot carpets and air conditioners. Even in the kitchen, there are more households that use IH cooking heaters, rather than gas.

When comparing heating efficiency from fossil resource consumption, air conditioners have the highest efficiency. Heat pump technology is used for air conditioners. The mechanism will be described later in detail, but the heat pump can draw heat from the outside up to six times the electricity consumed and supply it to the room. Since the conversion efficiency from oil to electricity is about 40%, it has a heating effect that is more than twice the heat from combustion of petroleum.

Electric heaters are heating devices that similarly use electricity, but they are less efficient than oil stoves. It is because electricity has already abandoned 60% of fossil resources in the power plant in the form of heat, and the remaining 40% will be directly turned into heat indoors. A heat pump also converts electricity to heat, but since it pumps up heat many times than that, it is highly efficient. Moreover, the air conditioner has a lower risk of fire than the oil stove, and the indoor air is not going to be polluted, so it is convenient for the consumer.

The energy used in the household sector will continue to increase in the future. Electricity can be made from petroleum or gas, or it can be made from renewable energy such as solar or wind power. Promotion of low carbonization in the household and business sectors shall be considered based on the premise that the energy to be used is consolidated into electricity.

3.3.4 Eco Houses Are Also Friendly to Their Occupants

Japan has created various energy-saving products and pursued energy efficiency, but energy saving measures have not sufficiently advanced for buildings. Even with existing buildings, the introduction of double glazing and heat insulation enhances thermal insulation property and air tightness, and the efficiency of energy use is dramatically improved. Zero-energy housing that is comfortable without introducing energy from the outside is one ideal form.

Double glazing glass that is indispensable for the realization of the zero-energy housing is PairGlass, which consists of several sheets of glasses stacked together. Low-E double glazing glass with thin film coating of silver on the hollow layer side of the glass has been attracting attention for building use. AGC Asahi Glass provides multiple line-up of Low-E double glazing. In the area west of the Kanto region, solar radiation shielding type glass that raises the heat shielding effect by stacking multiple layers of silver is said to be popular. On the other hand, in the Tohoku and Hokkaido regions, the solar radiation acquisition type glass that takes in solar radiation moderately by using only a single layer of silver is said to be popular. In both cases, the values are the same level with regard to the heat transmittance rate for evaluating heat transferability, and there is no difference in the insulation effect.

In Japan that has a small land area and where houses are compact, windows are required to be about 100 mm thick in many cases. To realize adequate heat insulation even with this thinness, it is important to partition the hollow layer of the PairGlass into multiple layers to suppress air convection in the hollow layer. The triple glass shown in Fig. 3.10 uses three glasses and enhances heat insulation by enclosing argon gas or krypton gas in the hollow layer. Also, since the window consists of glass and frame (sash), the performance of the frame must also be improved. In future zero-energy housing, it is thought that windows that combine triple glass with thin high insulation resin sash and resin composite sash will be adopted.
Fig. 3.10

Structure of triple glass. (Courtesy: AGC Asahi Glass)

Insulation properties of buildings have not only a significant impact on energy issues, but also on the health of their occupants. The Ministry of Land, Infrastructure, Transport, and Tourism conducted surveys in cooperation with the Ministry of Health, Labor, and Welfare and medical institutions on the death rate for each season by cause of death and the cause of accidents that occurred indoors in which injured persons were taken to hospitasl by ambulance. As a result, seasonal fluctuations were found in the cause of death due to the vasculature/cardiovascular system and the cause of death in residences. There are many cases of heat shock in the winter when the blood pressure rapidly changes due to temperature differences in the bathroom and dressing room. Houses with large temperature differences have a higher risk of people falling sick.

A report by Professor Shunji Ikaga of Keio University presented at the Architectural Institute of Japan is also very interesting. According to a questionnaire conducted for 5500 houses and 19,000 people living in highly insulated and highly airtight houses, there was a clear difference in the prevalence rate of illness before and after the people moved in. An 84% improvement was seen in cerebrovascular diseases, while an 81% improvement was seen in heart diseases. Improvements were also seen in all 10 diseases investigated including allergic rhinitis and atopic dermatitis.

Since insulated houses have uniform indoor temperature, vascular diseases such as heat shock are unlikely to occur. Also, since highly condensed and airtight houses are less susceptible to dew condensation that cause molds, it is thought that various symptoms such as allergy and atopy have improved. Higher insulation and higher airtightness of houses also lead to better quality of life (Figs. 3.11 and 3.12).
Fig. 3.11

Case examples of triple glass

Model houses displayed at “Ene-Mane (Energy Management) House 2014,” an exhibition themed on “houses in 2030” in which universities and companies collaborate to construct and display model houses. Both model houses incorporated low-e, gas filled triple glass manufactured by AGC Asahi Glass.

Fig. 3.12

Changes in disease prevalence rate due to improved insulation and airtightness performance and improvement rate. (Source: Ikaga et al. 2011)

3.3.5 The Latest Heat Pump Situation

Within the household, hot water supply, in particular, consumes a lot of energy. Japan is at the forefront of the world with regard to energy saving equipment in this field. One of these equipment is an electric water heater called EcoCute, which boils hot water with the heat of the air. EcoCute is based on a heat pump technology that enables extracting energy using temperature differences.

Currently, the power generation efficiency of thermal power plants in Japan is 42% on average. When you boil water with EcoCute, you can get about six times more energy, so multiplying 42% by 6 indicates that about 2.5 times more heat can be produced.

EcoCute has been on the market for more than 15 years, but during this time heat pump technology has evolved remarkably, prices have declined, and water heaters has consequently become increasingly popular. As shown in Fig. 3.13, the Heat Pump & Thermal Storage Technology Center of Japan has estimated the introduction of household heat pump water heaters in the future. The low variant represents the current trend with no additional countermeasures, the medium variant represents the case where measures are taken such as subsidies for introducing the water heaters, and the high variant represents the case where stronger measures are implemented to accelerate their introduction. According to this estimate, there will be 3–4 times as much stock in 2040 compared to the current situation.
Fig. 3.13

Estimated number of household heat pump water heater introduced. (Source: “Survey on Prospects of HP Diffusion,” Heat Pump & Thermal Storage Technology Center of Japan)

Heat pumps are used not only in EcoCute but also in various household appliances. Household air conditioners are a typical example. Due to technological progress over the last 20 years, the energy efficiency of air conditioners has doubled. Most freezer-refrigerators have a built-in heat pump, and heat pump type models are available for hot water floor heating, washing and drying machines, and hot water snow melting systems.

There are many heat pump type models in industrial air conditioning, freezer-refrigerators, and hot water supply equipment. Recently, cases of introduction of these equipments are increasing even at monozukuri sites. With the initial technology, it was possible to raise the temperatures of water to about 60 degrees (Celsius), so the industrial use was limited, but recent technology has made it possible to raise it to 90 degrees. If heating temperatures to this extent can be secured, these equipments can be used for heating and drying foods, as well as at chemical plants, electronic parts factories, and pharmaceutical factories (Fig. 3.14).
Fig. 3.14

Estimated energy-saving effects of introduction of household heat pump water heaters. (Source: “Survey on HP Diffusion Forecast,” Heat Pump & Thermal Storage Technology Center of Japan)

3.3.6 Domestic Fuel Cells Packed with Japanese Technologies

Along with the electric water heater EcoCute, household fuel cells known as Ene-Farm are promising as energy saving equipment that can be used for hot water supply in the home. There are two types of fuel cells that supply electricity and heat: solid polymer type using hydrogen and solid oxide type directly using city gas. The first type of Ene-Farm refers to a product that extracts hydrogen from city gas, LP gas, kerosene, etc. and produces electricity when the hydrogen reacts with oxygen in the air. About 37% of the gas and oil input to produce hydrogen is converted into electricity, while 50% of the thermal energy generated in the process is used to produce hot water. Therefore, a total of 87% of the input energy can be used. Only 13% is lost.

Since the efficiency of electric power reaching the home from centralized thermal power plants is about 37%, the amount of electricity generated by domestic fuel cells has reached the level of centralized thermal power generation. Therefore, using the hot-water supply of domestic fuel cells is like using waste heat thrown away at a centralized thermal power plant.

EcoCute and Ene-Farm are a crystallization of the energy-saving technology in which Japan takes pride. EcoCute is a product that Japan made almost from zero. Refrigerators and air conditioners once used CFC as a refrigerant. Refrigerant is indispensable for pumping in and pumping out heat, but CFC has been problematic, as it is an ozone depleting substance. Japan has succeeded in replacing it with CO2.

Ene-Farm is more technically advanced. Technologies for extracting hydrogen from LP gas and ceramics technology, which is indispensable for fuel cells, can be considered an area where Japan has expertise, and their elemental technologies are refined day by day. Products that are close to power generation efficiency of 45% will probably come out soon.

Ene-Farm, which uses solid oxide fuel cells, generates electricity at a high temperature of about 700 degrees (Celsius), so power generation efficiency is high, and it is 52% in Osaka Gas products. Ceramics is used in this type of fuel cells, and technologies in which Japan excels are utilized.

EcoCute and Ene-Farm use heat for hot water supply. Hot water storage tanks made in Japan have higher performance than overseas products. There are similar products in the U.S., but the final energy efficiency is inferior due to low thermal insulation performances of the tanks, and they are not widespread. Hot water supply accounts for slightly less than 30% of the energy consumption of households and business divisions. Even if you look at the world as a whole, the demand for hot water for taking a shower or bath is quite large. This reduction in energy consumption greatly contributes to the improvement of energy efficiency and low carbonization.

3.3.7 Globalize Japanese Environmental Technologies

Japan, which leads the world in heat pump technologies in the fields of air conditioning and hot water supply, should contribute to the world’s low carbonization with these advanced technologies, and at the same time, this should also lead to Japan’s economic growth. Among Japanese companies, Daikin Industries, which is at the forefront of such technologies and boasts the world’s largest share in the field of air conditioning, has placed global strategy as the pillar of its corporate management. The key points of the company’s success can be summarized into the following three points.
  1. 1.

    “Open Technology Strategy” – Strategy for Promotion of Energy-Saving Air Conditioners through Inverters -

Daikin Industries developed an “Open Technology Strategy” for expanding the inverter air conditioner market by providing inverter technology, which is the essential part of the company’s technology, to Gree Electric Appliances, the company with the largest share in China. As a result, in China’s air-conditioner market, the ratio of inverters, which is about 30% more energy-saving compared to non-inverter machines, has rapidly expanded, and the wave of inverterization is spreading throughout Asia.
  1. 2.

    Simultaneous development of refrigerant and air conditioners – Speedy response to environmental issues -

Daikin Industries is the only manufacturer in the world to both manufacture and sell air conditioners and refrigerants. As global environmental regulations became stricter, the company quickly adopted refrigerant control that matched the nature of the refrigerant, thereby achieving both energy saving and environmental performance at the same time. As a result, Daikin developed a new refrigerant called “R32,” which reduced the global warming potential to about one-third of existing refrigerants. The company developed the world’s first room air conditioners that adopted this refrigerant, and they are sold in 43 countries as of March 2015.
  1. 3.

    Split/multi-split type air conditioning – Meticulous refrigerant control technology -


“Multi-technology” for separately controlling multiple indoor units with one outdoor unit to selectively use cooling and heating is realized by Daikin’s refrigerant control technology. The company started development and sales of multi-split air conditioners for buildings in Japan in the 1980s, and realized the flexibility of construction and packaging of design and construction. Based on domestic success, the company has deployed its business model to Europe, Asia, and China, and spread Japanese style air conditioning culture.

In addition to Daikin Industries, other major air conditioning manufacturers in Japan such as Toshiba, Hitachi, and Mitsubishi Electric are rapidly advancing globalization through alliances with foreign companies.

Meanwhile, EcoCute, which succeeded in commercialization in the world for the first time in 2001, exceeded 5 million in the number of units sold at the end of March 2016, but its global expansion has been delayed.

Pressed to respond to environmental issues, South Korea and China are also aiming at switching from boilers heat pumps for hot water supply and heating. There is also concern that Japanese heat pump hot water supply equipment will become obsolete unless Japanese companies steer their global expansion as they did with air conditioning.

Under these circumstances, Panasonic began collaborative research with RWTH Aachen University in Germany in “electric power management technology for heat pump hot water heating systems.” In addition, Mitsubishi Electric transferred the design and development functions of heat pump heaters marketed in Europe to a subsidiary in the UK, and aims at increasing market share by speeding up the introduction of new models and reducing costs. Such moves toward globalization have been emerging.

In the future, it is expected that heat pump hot water heaters will bloom at once in China, which is a huge market, and the global strategies of Japanese companies, including technology and sales alliances with local companies and foreign companies, will be further tested.

3.4 Low-Carbon Technologies for Monozukuri

3.4.1 Shift from Blast Furnaces to Electric Furnaces

While agriculture, forestry, and fisheries make use of biological resources derived from solar energy, monozukuri (making things) is an activity to produce various artificial objects using underground resources that did not exist in the material cycle of the natural world. Here, I would like to take up steel, which has the highest energy consumption in the monozukuri process.

Steel can be produced by the blast furnace process (hereinafter referred to as blast furnace process) or the electric furnace process. Iron ore, which is a natural resource, is used in the blast furnace process. Iron ore refers to iron oxide. If iron ore is cast into a blast furnace together with coke, which consists primarily of carbon, pig iron is produced as oxygen is removed from the iron oxide. Various steel products are created by processing this pig iron.

About 600 kg of coke (carbon) is used to produce one ton of iron. Theoretically, the required amount of carbon is 202 kg, so it means that two-thirds are not used. Although the overall iron and steel process has become more efficient because of technological development, the processing and molding process is a multi-stage process, so if a slight loss that occurs at each stage accumulates, this could turn into a significant loss. In the future, to what extent efficiency can be increased depends on investment, but it is not easy to reduce 600–400 kg.

Meanwhile, iron that is used in bridges, buildings, railroad tracks, automobiles, etc. that exist in society is recovered as scrap once its service life as a product comes to an end. The scrap iron, however, is melted in electric furnaces, molded, and used as steel products once again. The energy used in the electric furnace process to produce one ton of iron can be calculated in terms of the amount of carbon required for the process. This is about 300 kg, about half of the amount required in the blast furnace process.

Energy required for processing and molding cannot be reduced significantly even in the electric furnace process, but the direction of reducing the overall energy consumption is visible. Currently, electricity is used to melt the scrap iron. Fossil resources are burned, and the heat generated is converted into electricity, which, in turn, is converted into heat to melt the iron. If the iron can be directly melted with the fossil resources, the amount of carbon used per one ton of iron can be reduced to about 150 kg.

Thinking in terms of energy, rather than mining iron ore and producing iron in blast furnaces, far less energy is consumed by taking advantage of scrap iron and producing iron in electric furnaces. In addition, the direction of technology development to reduce the energy consumption is visible in the case of the electric furnace process. This applies not only to iron but also to cement, aluminum, etc. If a social system in which resources that lie under urban mines are recovered and recycled can be created, it is possible to significantly reduce carbon in the monozukuri sector.

3.4.2 Aluminum Is an Excellent Material in Terms of Recycling

Aluminum is produced from an ore called bauxite, which consists mainly of aluminum hydroxide (about 25% of the aluminum content). The energy used in creating the product can be broken down into the following process: Mining (transport), production of aluminum oxide from bauxite, reduction (electrolysis), and molding.

As described above, no energy is theoretically required for transport. The same hold true for molding and processing. If a material is heated to near the melting point, it becomes soft and can be easily molded. If heat is recovered when it cools, this heat is the same amount as that required during the heating process. If this recovered heat is used to heat the next sheet, and the process is repeated, no additional energy would be needed.

Cutting is among one of the processes, but if the material is melted and then solidified in separate portions, the only energy required would be the heating process, and if that heat is recovered, no additional energy would be required. There would be zero theoretical energy required for processing thick sheets into thin sheets, cutting, machining, molding or processing.

To produce one ton of aluminum, 20 GJ of energy would be required in the process of producing aluminum oxide from bauxite. In the relevant reduction (electrolysis) process, carbon electrodes that will wear out will be used, so together with the power required in the process, 130 GJ of energy will be used. This brings the total to 150 GJ. It is a high value that is five times the theoretical energy.

Recycling of aluminum is also very popular. According to the Japan Aluminum Association, the energy used to produce regenerated mass that is made by recycling scrap, etc. is about 3% of that required to produce new bullion from bauxite. Using scraps is far more efficient than using ores, and it can be said that the scraps are an excellent resource in terms of energy consumption.

3.4.3 Achieving Material Cycling of Rare Metals

The existence of urban mines is extremely important in low carbonization in the monozukuri industry. Urban mine is a concept that was proposed more than 30 years ago, but it came to be recognized by the general public only about 10 years ago when the prices of rare metals that are indispensable to electronic devices such as mobile phones and personal computers began soaring.

Rare metals are literally very scarce, and there are many mining areas that are unevenly distributed. For example, small amounts of dysprosium are added to neodymium magnets used in hybrid and electric vehicle motors in to prevent deterioration of their magnetic force. Nearly all the dysprosium on the earth is in China, and if imports stop, it will be no longer be possible to produce hybrid vehicles and electric vehicles. Urban mines are important not only in terms of low carbonization but also in terms of resource security.

Fortunately for Japan, where electronic devices are widespread, large amounts of rare metals are dormant, so it is said that if all unused products can be recovered, these urban mines alone can satisfy domestic demand. To that end, it is of course necessary to establish a mechanism for material cycling.

It was precisely for this reason that the Small Home Appliance Recycling Act was enacted in April 2013. In the past, small appliances such as personal computers, mobile phones, smart phones, digital cameras, and gaming devices were not subject to recycling laws, and had been classified as non-combustible waste. The intention here is to turn these appliances into resources by properly creating a mechanism of recycling.

Renet Japan, a certified operator under the Small Home Appliance Recycling Act, offers the service of collecting small home appliances such as personal computers and smartphones and recycling them by taking advantage of couriers and the Internet (Fig. 3.15). The key feature of this service is the convenience that consumers find in being able to apply for the service from their home any time around the clock and having courier companies come to their home for pick up, as well as data security, or in other words, the thorough implementation of complete erasure of stored information, so that consumers can request for the service with confidence.
Fig. 3.15

Small household appliances collection service using home delivery services. (Courtesy: Lynette Japan Co., Ltd.)

Renet Japan has established partnerships with about 100 municipal governments in 2 years after it started the service. These municipal governments notify their residents about the company’s courier and collection service as part of their administrative services. In Kyoto City, about 10,000 personal computers were collected in just 2 months.

Since the Small Home Appliance Recycling Act is a law aimed at promoting recycling and lacks penal regulations, there are reportedly some areas where recovery of small home appliances has not progressed sufficiently. Although this is an administrative service, the cooperation of the residents cannot be gained if it is too troublesome to use the service, or there remain concerns about the handling of data. It is precisely in this area that ideas that are unique to the private sector regarding such services should be taken advantage of.

3.4.4 Expectations for Dissemination of Industrial Heat Pumps

At monozukuri sites, ordinary boilers are generally used in processes where heating is required. Among them, such applications as hot water supply, washing, drying, and low temperature heating (fermentation, aging, etc.) require heating below 100 °C. In such cases, it may be possible to replace the boilers with heat pumps. In the past, large-scale centralized equipment such as large boilers were used, but by replacing them with distributed-type equipment such as industrial heat pumps, it may be possible to achieve significant energy savings by reducing waste such as piping loss and drainage loss.

Figure 3.16 shows an example of heat pump application. Conventional heat pumps could be used for heating up to about 60 °C, but now that high-temperature heat pumps have been developed, their use in the food sector has spread remarkably. In addition, processes in which they can be used have increased in the medical, chemical, and other fields.
Fig. 3.16

Heat pump application destinations. (Source: Heat Pump & Thermal Storage Technology Center of Japan)

Industrial heat pumps can be roughly classified into two types depending on the positioning of the heat to be used.

One of them is the waste heat recovery type heat pump that effectively utilizes the heat that used to be discarded. At monozukuri sites, waste heat is recovered and utilized in various situations, but in some cases, the heat is irrecoverable and released into the air. The heat pump can effectively use waste heat as a heat source for temperature zones around several tens of degrees that are difficult to use. In the case where there is a time lag between the time when heat is generated and the time when heat is used, thermal energy can be utilized without waste by installing a thermal storage tank for storing the generated heat.

The other type is a heat pump that performs simultaneous heating and cooling. Although there are not a few cases at food factories, etc. where both the cooling and the heating steps are present, the heat pump is originally a technology in which heat is removed from one side and emitted to the other side. The side from where heat has been pumped out is cooled, while the other side where the heat has been pumped in is heated. Energy efficiency is nearly doubled if cooling and heating are performed simultaneously instead of separately. This would lead to energy saving within an entire plant.

For example, at a noodle factory, water is boiled in a boiler when noodles are boiled. The boiled noodles are cooled in a chiller filled with cold water. By installing a heat pump between these two steps, hot water can be produced on one side by collecting heat, while cold water can be produced on the other side by removing the heat. A certain factory succeeded in reducing CO2 emissions by 31% and energy consumption by 35%.

In 2015, Japan drew up draft pledge aimed at reducing greenhouse gas emissions beyond 2020. The target is to achieve a 26% reduction in greenhouse gas emission levels (about 1.042 billion tons of CO2) in FY2030 compared to FY2013 (approximately 25.4% reduction compared to FY2005). The Heat Pump & Thermal Storage Technology Center of Japan predicts dissemination of heat pumps for domestic and industrial use. It has estimated the effects of energy savings in the medium-level case and the impact on the reduction target in draft pledge (Fig. 3.17). According to the estimate, more than 20% of the target can be achieved by increasing introduction of the heat pumps.
Fig. 3.17

Effects of CO2 reductions through the introduction of heat pumps. (Source: Heat Pump & Thermal Storage Technology Center of Japan)

Theoretically, it has been known that a heat pump that pumps up heat from the environment and utilizes that energy is correct. That is because it is inefficient to burn fossil fuels to secure low temperatures, such as a hot water supply. Places that directly burn resources will likely disappear more and more in the future.


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Open Access This chapter is licensed under the terms of the Creative Commons Attribution 4.0 International License (, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The images or other third party material in this book are included in the book's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the book's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

Authors and Affiliations

  • Hiroshi Komiyama
    • 1
  • Koichi Yamada
    • 2
  1. 1.Mitsubishi Research Institute, Inc.Chiyoda-kuJapan
  2. 2.Center for Low Carbon Society StrategyJapan Science and Technology AgencyChiyoda-kuJapan

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