COUNTRY PROFILE: Japanese Solar Program Emphasizes PhotovoltaicsA country which is highly vulnerable in terms of energy sources, Japan is placing major expectations on the development and introduction of new sources of energy which can serve as alternatives to oil. At the same time, the Japanese government is strongly committed to improving the environment. Alternative energy sources are recognized as having a dual benefit: improving energy security and helping to mitigate global environmental problems such as acid rain and the warming effects attributed to carbon dioxide gas.
A cabinet decision in October 1990 set a goal of 5.3% (34.6 million kl in crude oil equivalent) of Japan's total primary energy supply to be provided by alterative energies by the year 2010. New energy sources include alcohol fuels, solar energy, black liquor (by-product of the pulp and paper industry), and charcoal fuel. If geothermal energy is added, the figure is 6.2%
To put this in context, in 1989, total energy consumption in Japan was 500 million kl of crude oil equivalent, of which 58% was oil, 17% coal, 10% natural gas, 9% nuclear energy, 4.6% hydroelectric, and 1.4% new energy sources.
New Sunshine Project
The origins of Japan's official alternative energy program go back to 1974, when the Agency of Industrial Science and Technology of the Ministry of International Trade and Industry (MITI) initiated the "Sunshine Project" to promote research and development on alternative energies. A more comprehensive approach is reflected in the "New Sunshine Project" which was established in 1993 with the aim of "sustainable growth through a simultaneous solution of energy and environmental constraints." The New Sunshine Project Headquarters is responsible for general management of the programs for new energy sources and energy conservation.
NEDO
NEDO (New Energy and Industrial Technology Development Organization) was established in 1980 as a central body to promote the research and development of technology related to new energy sources. It is responsible for promoting alternative energies such as solar energy, geothermal energy, energy conversion and storage, alcohol biomass energy, etc. In 1993, NEDO's activities were expanded to include energy conservation, diffusion of alternative energy technologies, and demonstration of energy conservation and alternative energies technologies overseas.
NEDO's Solar Energy Department is responsible for the following areas:
- Photovoltaic power generation technology
- Solar energy systems for industrial use
- Development of large-scale wind power generation
- International cooperation and projects.
Solar R & D Activities
Photovotaic technology receives the greatest emphasis in the solar program. In 1993, it was funded at the level of Y8,360 million ($US 76 million at the 1993 exchange rate). Activities in the solar thermal area focus on the use of solar energy for industrial purposes and high-tech glazings, but have much smaller budgets.
Photovoltaics R & D
The goals of the Photovoltaics Program are:
- To reduce the cost of PV modules to Y210 per watt by the year 2000, with focus on thin substrate polycrystalline solar cell and thin film solar cell.
- To increase the efficiency of single crystalline silicon solar cells and compound crystalline solar cell to 30 - 40 %.
- To reduce the cost and improve the reliability of PV system peripheral components.
To achieve those goals, R & D is being carried out in the following areas:
- Improved manufacturing technology Improved efficiency, reliability and cost performance of amorphous silicon, CdTe, thin film polycrystalline silicon, and CuInSe2 cells Super high-efficiency solar cells.
- Demonstration projects, including demonstration projects and field tests in several Asian countries and in Australia.
- Balance-of-system components, e.g., low-cost inverters for adapting DC output to AC loads and storage battery for stabilizing the power output.
Solar Industrial Process Heat Technology
Solar concentrator for intermediate temperature applications:
A high efficiency, low-cost collector has been developed to match heat collection temperatures. This involves development of an improved vacuum-type compound parabolic collector with a reflective mirror on the inner wall of the glass housing for medium temperature applications (90 - 150C).
Energy conversion technology using chemical reaction:
Researchers have worked on a chemical heat pump which can efficiently raise temperatures collected at 80C to 150 - 200C. This would facilitate wider use of solar energy for production of steam for industrial processes. (See illustration.)
High quality heat insulating material:
High performance thermal insulation has been developed to reduce heat loss in the piping and heat storage systems.
Advanced Heat Process Technology
High Efficiency Chemical Refrigeration using Solar Heating:
Demand for cold at temperatures of less than -20C (F class temperature level) is very high, but cold heat obtained from solar heat is typically in the range of -5 to -10C. Research in refrigeration technology is being conducted to expand the temperature obtained by solar thermal energy to a lower or higher range. The goal is the development of a stand-alone freezing and cooling system using solar heat of 130 - 150C which is capable of functioning in temperature levels down to -20C using the chemical reaction of the heat of metal hydride materials with hydrogen gas.
Passive Solar Technology
Work in this field involves development of transparent insulation material and electrochromic glazings with a practical service life and excellent optical characteristics for such applications as building windows and other purposes.
Solar Energy Promotion
In 1980, the Japanese government implemented a program to promote solar energy systems. This involved compilation of performance standards, development of performance evaluation tests, low interest loans to manufacturers to promote cost reduction, training of engineers and technicians, low interest loans for installation of solar systems on private homes, and promotion of solar installations in government and public buildings.
Solar Water Heating Systems
The history of the solar water heater in Japan goes back to the 1940's after World War II. The solar water heaters then available were of either the bread box type or cylindrical storage type. In the 1960's, such solar water heaters were mass-produced. But with the availability of cheap oil, they lost popularity.
The first oil shock of 1973 again raised the popularity of such heaters, and new types of solar water heaters were beginning to be developed by many manufacturers. Most of the solar water heaters currently available on the market are of the thermosiphon type which emerged in 1976. By improving thermal insulation, the thermosiphon type water heater insures that hot water produced during the day can be kept at night with little drop in temperature. A typical solar water heater consists of 3 to 6 m2 of collectors and a storage tank of 200- 300 liters. No more than two hot water heaters can be placed on the roof of many Japanese houses, which are not designed for the weight of a heavy storage tank.
Those wanting a larger quantity of hot water select an active solar energy system in which a larger storage tank is placed on the ground, the solar collector on the roof, and a circulation pump used. But the cost and installation is more expensive than the thermosiphon solar water heaters and the installation takes longer, so sales of active solar systems are much lower than thermosiphon solar water heaters.
Market Trends
About 4.5 million thermosiphon solar hot water systems are currently in use. A total of about 400,000 active solar systems had been installed by 1992, mostly in single-family homes.
Despite the government's popularization measures taken since 1980, the market for solar thermal systems has been shrinking continuously for the past several years due to the long payback period for solar systems and a significant drop in cost of conventional energy resulting from a drop in the oil price on international markets and the appreciation of the yen against the U.S. dollar.
In 1985, 257,000 solar hot water heaters were produced, but this had decreased to 80,000 in 1992. Sales of active solar systems declined from 38 thousand units to 16,000 for the same years.
PV Production
In 1993, Japanese production of solar cells was as follows :
single crystalline silicon 1.4 MW polycrystalline silicon 5.4 MW amorphous silicon 8.9 MW others 1.0 MW TOTAL 16.7 MW Captions:
In much of Mongolia, the established lifestyle is a nomadic one. Portable PV power systems are being field tested which are lighter and more compact to improve portability and reliability.
Schematic of chemical heat pump system for boosting temperature of conventional solar heat from 80C to 150 - 200C.
Solar collectors at the Fugaku Golf Club provide shading for the parking area as well as hot water for showers, space heating and cooling.
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