Debate on the energy future of this nation is heating up. The central theme is the level of nuclear energy needed to power Japan in 2030.
Electricity generated at nuclear power plants is only one source of energy used by households and factories.
It is now important to widen the scope of the debate and give serious consideration to energy sources other than electricity for the sake of meaningful, in-depth discussion.
USING GROUND SOURCE HEAT FOR COOLING
With only two out of 50 nuclear reactors around the nation generating electricity this summer, many people in Japan are probably trying cut back on their usage of air conditioners to save energy.
Most air conditioners are powered by electricity. But other forms of energy can do the job just as well.
If energy sources other than electricity are used, demand for atomic power will be reduced significantly.
Tokyo Skytree, the world’s tallest freestanding tower that opened to the public in May, has adopted the nation’s first local heating and cooling system using ground source heat.
Below the foundations of this structure are many special tubes buried to a depth of 120 meters.
Underground temperatures are generally lower than outside air temperatures in summer, and higher in winter.
The system used at the Skytree is designed to recover ground source heat for air conditioning at the aquarium and stores in the shopping mall within the site.
The system, supported by huge water tanks to store low-temperature heat and state-of-the-art heat source equipment, boasts energy efficiency that is more than 40 percent higher than that of individual air conditioning of facilities.
In the Hakozaki district, located some 3 kilometers southwest of the Tokyo Skytree, buildings use the thermal effects of the Sumidagawa river, which runs nearby, for air conditioning. This allows the buildings to slash their consumption of electricity from outside sources.
Solar-powered water heaters have long been used in Japan as a means to provide heat used for daily life, such as supplying hot water.
A boom in sales of solar-powered water heaters that began after the oil crises in the 1970s began to cool when it became clear that underhanded dealers proliferated and the government withdrew policy support subsidies.
In recent years, however, a growing number of welfare facilities for the elderly and hospitals in Japan have been introducing equipment using solar heat or ground source heat.
COGENERATION FOR HIGHER ENERGY EFFICIENCY
There are many untapped heat energy sources available, such as solar and Earth heat, heat in the sea and rivers, waste heat from subways and transformer substations and heat generated when garbage is burned.
We should do more to discover and tap such heat sources.
First of all, much of the heat generated in the process of producing electricity is wasted.
Thermal power plants burn fossil fuels like oil, coal and natural gas to generate power.
A typical thermal power plant has a power generation efficiency of only around 40 percent. That means the plant can convert only 40 percent of the energy it consumes into electrical energy. The remaining 60 percent produces waste heat.
At a nuclear power plant, 70 percent of the energy consumed only produces hot waste water that is released into the sea.
In fiscal 2011, Japan spent some 23 trillion yen ($293.5 billion) on imports of fossil fuels and used slightly less than 30 percent of the amount to generate electricity.
It is a great pity that such a large chunk of the energy extracted from these fuels is simply wasted as useless heat.
Increasing attention is being paid to cogeneration as a means to reduce waste in thermal power generation and thereby contribute to efforts to stem global warming.
Cogeneration involves generating both electricity and useful heat by, for instance, using waste heat from power generation plants to produce hot water.
Cogeneration can produce electricity at an efficiency rate that is twice as high as that of a typical thermal power plant.
Small-scale cogeneration is suitable for building up a dispersed and decentralized energy system.
Germany and countries in Northern Europe lead the world in use of cogeneration.
In Japan, home-use fuel cells powered by city gas are gradually gaining popularity. But use of cogeneration by local communities has been showing little growth.
Strict regulations on the construction of pipes for supplying heat, along with soaring fuel costs, are posing major obstacles to the spread of cogeneration.
The three different energy mixes in 2030 that the government has presented as possible options for its new energy policy all envision raising the share of cogeneration in overall electricity generation to 15 percent, about five times the current figure, by then.
The Ministry of Economy, Trade and Industry has set up a new section to promote cogeneration. It should adopt bold measures to expand cogeneration while trying to enlighten small and midsize businesses and local governments about the benefits of the approach.
INTERNATIONAL COMPETITION OVER ENERGY CONSERVATION
How effective would such policy measures actually be?
The government’s three options for future energy supply are all based on the assumption that the nation’s power consumption will decline by 10 percent from the current level by 2030.
The reduction in Japan’s final energy consumption, the total energy consumed by end users like households and businesses-- including the use of heat and transportation fuels--will be 20 percent, according to the government’s projection.
But these forecasts appear to be pretty conservative.
Based on the strenuous power-saving efforts that have been made by the public since last year’s triple disasters, the Japan Research Institute Ltd. has estimated the maximum possible reduction in energy demand to be 15 percent.
A group of lawmakers of the ruling Democratic Party of Japan committed to mapping out a plan for phasing out nuclear power generation altogether has proposed a 20-percent cut in power consumption and a 25-percent reduction in overall energy consumption by fiscal 2025 at the latest.
International competition over power and energy conservation is already intensifying.
The European Union has adopted a target of raising the region’s energy efficiency by 20 percent by 2020.
The EU provides strong policy support to a wide range of efforts for more efficient use of heat, such as measures to enhance the heat insulation of buildings and steps to bolster the energy efficiency of power generation plants. It also promotes the introduction of energy-saving technologies and equipment.
The EU’s energy policy is also designed clearly to help enhance economic growth and job creation.
Japanese society has been built on the assumption of mass production and mass consumption of energy, especially electricity.
Now, Japan needs to take all possible policy measures to promote power and energy conservation while expanding the use of renewable energy sources.
A clear commitment to creating a more energy efficient society will ensure Japan’s steady progress toward a future that is not dependent on nuclear power generation.
-- The Asahi Shimbun, Aug. 13
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