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Solar Energy to Be Widely Used in Buildings

China is currently cooperating with the Asian Development Bank on using solar energy in buildings, especially residential buildings, which is expected to involve an investment of US$150 million. Experts hail the program as a “milestone” in the use of solar energy.

It is reported that the Solar Energy Technical Innovation Demonstration Base, a program under the State Development Planning Commission, will start construction on the northern part of Beijing’s Asian Games Village. The model, being a three-story building with 9,000 square meters of floor space, will employ solar technologies to generate power and air conditioning. By combining solar materials with building materials, it will ultimately become a power-saving and environmentally-friendly demonstration building.

Development of Solar Energy

Globally, reserves of non-renewable sources of energy such as coal, oil and natural gas are declining drastically. Calculated by the proven reserves and the speed of consumption, petroleum, the main source of energy in the world, will be exhausted in 40 to 50 years. By that time, the energy crisis will become a major threat to the world. In the meantime, the sustainable development of human society demands coordination between energy development and environmental protection and ecological balance. Therefore, many countries are actively developing clean and renewable sources of energy, and solar energy is a typical one.

According to officials of relevant departments, coal makes up more than three-quarters of the energy consumed in China—a major reason for the country’s heavy air pollution. To reduce the pollution, work needs to be done centering around coal with low sulfur content and power-saving technologies. Another important option is to vigorously develop new sources of energy and renewable sources of energy, such as solar energy, wind-generated energy, geothermal energy and hydropower. This type of development is also necessitated by the excessive felling of trees, damage to vegetation and deterioration of the ecological environment as a consequence of energy shortages in rural areas. China has decided to focus on solar energy, hydropower, wind-generated energy, tidal energy and geothermal energy in its endeavors to seek new sources of energy.

Solar energy is a huge source of energy that does not pollute the environment. The solar energy Earth obtains per second is equivalent to the energy generated by burning 5 million tons of quality coal. Solar energy may be used in power-saving buildings such as greenhouses for growing vegetables. Solar energy collectors as a source of heating can be used to replace traditional furnaces. Solar water heaters and solar cookers can help save fuel in daily life. Solar energy can also be used for desalination, refrigeration and power generation. Solar batteries have been successfully used on man-made satellites and have now begun to be used on Earth.

For the time being, however, there are many obstacles on the use of solar energy on Earth. For instance, the absorption and reflection by the atmospheric layer shrouding the Earth reduces the amount of solar energy arriving on Earth. Moreover, on Earth half of each day is nighttime without sunshine, which, together with cloudy days and rainy days, prevents people from using solar energy adequately. Nevertheless, scientists firmly believe that solar energy represents a trend in the development of energy science in the new century. In an attempt to circumvent the unfavorable conditions, they have proposed to generate power with solar energy in space. That is, electric power will be first generated with solar energy in outer space, then transmitted through microwaves or lasers to a receiving device on Earth, and finally converted into electric power that can be used on Earth. This tentative idea has aroused widespread attention in the Chinese scientific community.

Utilization of Solar Energy

Solar energy has been widely used in the world. In many countries such as the United States, the Netherlands and Germany, solar energy has become one of the renewable sources of energy with the highest degree of commercialization and the widest application. Solar water heaters and solar air conditioners are becoming popular. In countries known for their energy shortages such as Israel and Greece, 40 percent of the households use solar energy. So far, Europe, the United States and Japan have experimented with solar water heaters, solar air conditioners and solar batteries in buildings that are to become a new style of solar energy architecture.

China is one of the regions in the world with an abundance of solar energy. In western China especially, annual sunshine exceeds 3,000 hours. It is estimated that if 1 million households in Beijing and its neighboring areas replaced coal with solar energy, there would be a reduction of 7.7 million tons of carbon monoxide, 35,000 tons of sulfur dioxide and 110,000 tons of dust discharged into the air within 10 years. Besides, 6 billion kwh of electricity could be saved.

The integration of solar energy devices and building materials will propel the development of solar energy, according to an expert at the energy conservation office of the Ministry of Construction. He said that the supply of hot water in residential buildings is a vital part of the infrastructure. At the moment, however, the 24-hour supply of hot water is still a luxury for most urban residents in China. Using solar energy could be a feasible solution.

Through 10-plus years of effort, China has made steady progress in the use of solar energy. In particular, solar water heaters are developing into a new industry. So far, there are more than 1,000 manufacturers of solar water heaters in China, with more than 30 million users. Both annual output and ownership lead the world. The all-glass vacuum solar water heaters developed independently by the Chinese are up to international standards and exported to Japan and the United States. China’s home appliance giants such as Haier are also entering the field, and hopefully, their solid financial strength and production capability will help standardize the market.

It is projected that if 100 million households used solar water heaters in China, relevant industries would be able to increase their output value by several 100 billion yuan.

Using solar energy in buildings will have broad prospects in China. First, China is a large energy consumer with the consumption of energy in buildings constituting quite a large proportion of that. Energy consumed for heating in Beijing alone makes up more than 10 percent of the national energy consumption. In some areas, energy for heating may make up more than 50 percent of the total energy consumed. Therefore, an increase in the number of solar buildings, especially residential buildings, could substitute or save conventional energy sources and help achieve sustainable development.

Owing to China’s huge population, only about 2 percent of Chinese households use solar water heaters nowadays. Although the State Economic and Trade Commission predicts that by the year 2005, 20 percent will own solar water heaters, the current market permits little optimism. For instance, in spite of rapid development, the solar water heater industry is still at a low level of industrialization.

Most of the enterprises that manufacture solar water heaters are small and medium-sized township enterprises. Few of them have an annual output value exceeding 100 million yuan. Their production scale is small and their production mode backward. Moreover, solar products have problems themselves such as poor quality and lack of matching parts. Using solar energy in buildings and combining solar energy with architectural techniques and design are still at the exploration, research and demonstration stage.

As for the issue of how China should develop its solar energy industry, experts have raised two proposals. First, the government should make some policies to support the industry and encourage enterprises to produce better products. Second, the government should devote great effort to the popularization of solar products. For instance, the government could mandate some buildings to use solar energy. If 5 to 10 percent of the buildings used solar water heaters, China’s solar industry would gain unusual momentum.

Some officials expressed the opinion that this idea deserves earnest study and agreed that the Chinese Government should attach great importance and render vigorous support to the use of solar energy.

(Beijing Review 01/25/2001)

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