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6.1 Concerned over Environment

<<The warming Globe>>

Of late, global warming is getting serious. The cause is increased emission of greenhouse effect gas, such as carbon dioxide, etc. due to increasing of consumption of coal and oil. The amount of carbon dioxide in the air, compared with 200 years ago, has increased by around 30% (See figure 6.1). Since the 19th century, human beings got to consume a lot of coal and oil as industry developed. The amount of carbon dioxide at the end of 20th would be nearly doubled if we consume them by keeping the same activities. As a result, the average temperature of the globe is expected to increase around 2。・higher than now.

With only 2。・increase, enormous influences would emerge.

Firstly, as global phenomena, a number of islands sinks in the sea as sea level rises. Furthermore, warming temperature contributes to abnormal climate affecting water circulation in everywhere in the world. As a result, areas, where floods frequently occur, and where droughts hit, would emerge.
In addition, other problems, such as increase of tropical infectious diseases like malaria, and food problem due to decrease of agricultural products and marine products, would bring up seriously situation across the world even with a slight increase of temperature.

In the case of Japan, heat-island effect would be accelerated in urban areas, sandy beach would decrease due to rise of sea level resulting in enormous increase of dangerous areas that are easily attacked by tidal wave and Tsunami.
Also, food problem would be our urgent concern as dependence on food imports is high.

Figure 6.1 Change of carbon dioxide emission from fossil fuel and carbon dioxide concentration in the air
Figure 6.1 Change of carbon dioxide emission
from fossil fuel and carbon dioxide concentration in the air

In utilizing secondary energy, the most convenient and valuable energy is electric energy (electric power).
Over the past 10 years, demand for electric power has greatly increased. That is because the energy can be converted easily to mechanical energy or thermal energy. It is efficiently utilized for many electrical equipments and devices for which it cannot be easily replaced with other energies.
However, those electrical equipments and devices are emitting carbon dioxide, indirectly though. Electric energy itself is clean energy but, we need to keep in mind that it emits carbon dioxide at the same time as electric energy is generated.

CO2 specific emission consumption vs. total electric power at all power stations.
(Amount of carbon dioxide developed by generating electric power of 1kWh)

Figure 6.2 CO2 specific emission consumption
Figure 6.2 CO2 specific emission consumption

* Specific emission consumption is getting lower because of expansion of nuclear power generation, efficiency improvement of thermal power generation, and LNG thermal generation which gives less CO2 emission among fossil fuel though electric power generation has increased.

Electricity we use is secondary energy, and it is produced by converting various primary energy and reprocess it. Out of total demand for primary energy like oil, coal, hydraulic power, liquid natural gas, and nuclear power, ratio of energy which is converted to electric power is called electrification ratio. Electrification ratio is apt to increase year after year, and is expected to increase continuously. As electric energy is able to change to light, power, heat source, and electronics, it gives a lot of possibility to play an important roll connected with with electronics to support IT society.

Figure 6.3 Transition and estimate of electrification ratio and electric power demand
Figure 6.3 Transition and estimate of electrification ratio

and electric power demand

As seen in the figure above, power consumption is increasing from year to year. In particular, demand for consumer sector including household, building and commercial use is growing resulting in higher ratio among total power demand. The reason why residential sector is growing is that home appliances such as refrigerators, TVs, air conditioners, washing machines, and electrified housing are spreading. Also, micro computers have been built in electric home appliances to always consume small power (standby power) to control additional functions such as automatic operation,
remote control, and display of status of Stop/Operation.
Standby power may be small but, the influence to total consumption across the country must be large as there are quite many appliances that consumes power day and night.
As to business sector, a lot of power including standby power is consumed by lightings and air conditioning at office buildings, hotels, departments, and convenience
stores, or by OA equipments like PCs and faxes.

As discussed above, power demand is expected to be increasing year to year, and still keep on. In order to control and reduce carbon dioxide emission:

- "Electricity saving"
- "Energy saving"
- "New energy innovation"

are to be strong measures for us to suppress electricity consumption, and we must tackle aggressively throughout the entire society.

<< Pushing ahead with "Electricity saving," "Energy saving." and "New energy innovation" >>

In order to reduce electricity consumption, "Electricity saving," "Energy saving," and "New energy innovation" are to be tackled.

1) Electricity saving
"Electricity saving" is to eliminate energy itself that is consumed in a wasted way. For example, frequently turning on and off the lights, turning off the main switch of electric appliances to eliminate standby power, higher setting temperature of refrigerators and air conditioners, and so on. 70 to 80% of companies who are tackling have introduced electricity saving of lights and air conditioners.

2) Energy Saving
"Energy saving" is to use energy with high efficiency to reduce energy consumption, or loss. What we can do is to use equipments with high efficiency, and home appliances are getting to be energy saving type which achieve high efficiency. Of late, in particular, power electronics technique has progressed to bring high performance and energy saving. In home appliances and consumer products, power electronics
technique has been implemented to inverters for lighting apparatuses, air conditioning, and cooking equipments. For example, implementing inverter circuit to lighting circuit of fluorescent bulb improves luminance efficiency by 10% or more saving energy by approx. 20% compared with traditional magnetic circuit voltage stabilizers.

3) New energy
New energy means newly developed energy to replace existing primary energies such as oil, coal, natural gas, etc. Implementation of new energy is greatly expected for its less limited resource and low environmental burden due to less emission of CO2 among alternative energy to oil.

Generally speaking, new energy is categorized into three types. One is "Renewable energy" which is clean and has no limit of resources such as solar energy and wind energy, Second is "Recycled energy" which use waste and exhaust heat. Third is "New form of utilization of traditional energy" which aims at higher efficiency of traditional energy use and harmonization with environment.

Renewable energy:
Power generations by Solar power, Hydraulic power, Wind power, Solar heat, Geothermal heat, etc.

Recycled energy:
Factory exhaust heat, Sewage heat, Utilization of wastes, Biomass, etc.

New form of utilization of traditional energy:
Cogeneration, Fuel cells, etc.