New energy is one of the five most decisive technical fields in the development of world economy in 2 1 century. Solar energy is a clean, efficient and inexhaustible new energy. In the new reality, governments all over the world regard the utilization of solar energy resources as an important part of national sustainable development strategy. Photovoltaic power generation has the advantages of safety, reliability, no noise, no pollution, less restrictions, low failure rate and simple maintenance, and plays a very unique role under the realistic conditions of vast and cold territory, diverse terrain and scattered residence in western China.
I. Overview of Solar Energy Utilization at Home and Abroad
1.l Current situation abroad
With the limitation of conventional energy resources and the increase of environmental pressure, many countries in the world have re-strengthened their support for the development of new and renewable energy technologies. In recent years, international photovoltaic power generation has developed rapidly. 1973, the United States makes a government-level sunshine power generation plan; 1980, photovoltaic power generation was formally incorporated into the public power planning, with a cumulative investment of more than 800 million US dollars. 1994 budget, the photovoltaic power generation budget reached more than 78 million dollars, an increase of 23.4% over 1993; 1997, the United States and Europe successively announced the "Million Roof Photovoltaic Plan", and the United States plans to install 1000 ~ 3000 MW solar cells by 20 10. Not to be outdone, Japan funded the "Roof Photovoltaic Project" 1997, with a funding of 92 million US dollars and an installation target of 7600Mw. India plans to produce 1998-002 solar cells with a total output of 150MW, including 50MW in 2002.
International photovoltaic power generation is developing from remote rural areas and special applications to grid-connected power generation and power supply combined with buildings, and photovoltaic power generation is transitioning from supplementary energy to alternative energy. Up to now, the annual sales volume of batteries in global solar has exceeded 60 MW, the conversion efficiency of solar cells has increased to more than 15%, and the system cost and power generation cost have been reduced to 4 USD /MW and 25 cents /kWh respectively. In terms of solar thermal utilization, due to the increasingly mature technology and increasing application scale, the annual sales of solar water heaters in the United States alone exceed 1 100 million US dollars. Solar thermal power generation has also made a breakthrough in technology. At present, more than 20 large-scale solar thermal power stations are in operation or under construction.
1.2 domestic status
The massive consumption of coal has become the main source of air pollution in China. China is rich in new and renewable energy resources, such as solar energy, wind energy, biomass energy, geothermal energy and ocean energy, and has broad prospects for development and utilization. The application of solar photovoltaic power generation began in 1970s, and the real rapid development was in 1980s. In the short time of 1983- 1987, seven solar cell production lines were introduced from the United States, Canada and other countries, which made the annual production capacity of solar cells in China jump from 200 kilowatts before 1984 to 4.5 megawatts before 1988. At present, solar cells are mainly used in communication systems and remote areas without electricity, such as remote county towns, villages and islands without electricity. The annual sales volume is about 1. 1 MW, and the effect is remarkable.
(1) More than 40 small photovoltaic power stations at county and township levels have been built, with a total installed capacity of about 600kw, of which Tibet has the largest capacity, reaching more than 450 kW; 1998 10 the largest photovoltaic power station in China is located in Amdo county, Naqu, Tibet, with an installed capacity of 100kw.
(2) Household photovoltaic power supply is widely used in Qinghai, Inner Mongolia, Xinjiang, Gansu, Ningxia, Tibet, Liaoning, Jilin, Hebei, Hainan, Sichuan and other places. According to incomplete statistics, up to now, about 6,543.8+0.5 million household photovoltaic power sources have been popularized in China, and the total power of photovoltaic cells is about 2.9MW.
(3)22 rural schools have established photovoltaic power stations with a total installed capacity of 57kw.
(4) 1998, the most difficult optical cable trunk line project in the communication history of China was built. There are 26 optical cable communication stations powered by photovoltaic cells, with an altitude of over 4500m, and the total power of photovoltaic cell modules reaches 100kw.
(5) 1996 A cathodic protection power supply system for Tazhong 4- Lunnan oil and gas pipeline was built, with a total power of 40kw. The system crosses the harsh and complicated Taklimakan desert, with a total length of 300 kilometers.
(6) 1995, 63 national key aid projects-Tibet radio and television transmitting and receiving project were powered by photovoltaic cells, and 2 16 sets of satellite TV receiving stations and * sets of FM transmitting stations were built, with a total power exceeding 300 kilowatts.
Second, the general situation of solar energy application in western China.
2. 1 natural resources
Western China is the largest geographical unit with high terrain in the world. It is also one of the regions with the richest solar energy resources in the world, especially Tibet, with thin air and high transparency. The annual sunshine duration is as long as 1600-3400 hours, and the average number of days with sunshine of more than 6 hours per day is between 275-330 days. The radiation intensity is high, with an average annual radiation of 7000 MJ/m2. The geographical distribution is increasing from east to west, and the annual change is peak-shaped, with unique resource advantages.
2.2 Energy situation
Most areas in the west are extremely short of energy. Over the years, we have actively and steadily developed geothermal energy, made great efforts to promote the utilization of solar energy, replaced oil and electricity in a planned and step-by-step manner, and appropriately developed wind power generation; According to local conditions, multi-functional complementarity, the combination of large, medium and small, mainly small and medium; Power grid construction should be synchronized with power supply construction, with equal emphasis on construction and management, development and energy saving, but the per capita installed capacity and annual power generation still lag behind the national average. Tibet, in particular, is the province with the smallest power generation and per capita electricity consumption in China. People without electricity still rely on butter lamps, diesel lamps and candles for lighting. Some household butter lamps can no longer be bought. The students do their homework in the dim light of the cow dung burning stove. Very few towns and villages use old diesel generators to solve short-term lighting problems. In view of this, it is difficult to develop thermal power without resources to build hydropower stations. Relying on the extension of the power grid, it is staggering to send "light" to the homes of farmers and herdsmen who live far away and are sparsely populated. Optical energy has become the people's long-cherished wish for many years, and the prominent power bottleneck has become an obstacle to Tibet's economic development and social progress, hindering the improvement of people's living standards, and affecting the people's pace of getting rid of poverty and getting rich, eliminating ignorance, and managing poverty and getting rich. This is the main source of poverty and backwardness. Undoubtedly, using solar photovoltaic power generation is an important and effective way to solve this problem.
2.3 solar energy application
There is sunshine everywhere, and there is electricity everywhere. The use of solar photovoltaic power generation in the western region has begun to achieve remarkable results in solving the problems of communication, broadcasting, television power supply and electricity consumption for people without electricity. Successful implementation of special solar energy plans such as "Light of Science", "Sunshine Plan" and "Ali Photoelectric Plan" has made it the first and largest area in China to implement special solar energy plans. Take Tibet as an example:
2.3. 1 photovoltaic power station
By the end of 1999, seven county-level independent photovoltaic power stations have been built, and six counties without electricity have been eliminated, with a total installed capacity of 450KWp, ranking first in the country, Amdo 100KWp photovoltaic power station is the largest in the country, and Shuanghu tracking photovoltaic station with an altitude of 5 100 meters ranks first in the world.
communication power supply
The photovoltaic power supply of microwave relay station is about 200KW or more; Telephone township power supply 100 kw; In the 600 km project near Tibet section of Lanssila optical cable communication project, near 100KW photovoltaic power supply was applied, and the photovoltaic battery power supply increased rapidly.
Radio and television power supply
In Shiquanhe, Gaize and Maimen coal mines, about 20 satellite TV receiving and broadcasting stations and TV differential turntable with photovoltaic power generation as power supply have been built, with a total installed capacity of about 20KW. Radio and television photovoltaic power supply system 100 sets, 100 kilowatts.
Photovoltaic water pump
Tibet has a huge area of waterless grassland, and the potential market demand of photovoltaic pumps is considerable, with broad application prospects. Six sets of photovoltaic water pump systems have been built in Shiquanhe, Ritu, Gaize, Nima and Zhanang, with a total installed capacity of more than 2 kW, which not only solved the drinking water problem of people and animals in this area, but also ended the history of relying on manpower to carry water, greatly liberating the labor force.
2.3.5 Household photovoltaic power supply system
Promote more than 30,000 sets of household photovoltaic power supply l0-300W system, with a total capacity of about 60 kW, which can be used by independent fixed families and nomadic families. It is portable, simple, safe and reliable, with excellent performance, and is very popular. Every household in Sanqing Village, Changzhuduo, Shannan has installed 40Wp photovoltaic power supply, and 25 farmers and herdsmen have solved the power supply problems of lighting, watching TV and listening to tape recorders, so it is called Sun Village.
2.3.6 School photovoltaic power station
Nearly 10 schools have built solar photovoltaic power stations, and the 2KW photovoltaic power station of Tangjiaxiang Primary School in Mozhugongka is the largest amorphous silicon photovoltaic demonstration power station in China. Up to now, there are more than 600 township schools in Tibet, all of which are boarding schools. It is very important to solve the problems of school power supply and audio-visual education as soon as possible to improve the scientific and cultural quality of the younger generation in Tibet, and it is also an important aspect of photovoltaic power generation application in the future.
2.3.7 Photovoltaic Power Supply System for Frontier Post
Most border posts in Tibet have no electricity, and more than 20 border posts have installed photovoltaic power supply systems, which have solved the power supply problems of lighting, watching TV, listening to tape recorders and communication, with each power of 1 ~ 2kW, greatly improving the working and living conditions of border officers and soldiers.
At present, seven counties in Tibet have built 10- 100 kW large-scale county-level solar photovoltaic power stations. The capacity of all kinds of solar photovoltaic facilities in the whole region exceeds 2MW, and more than 85,000 square meters of solar water heaters, 9. 1 10,000 sets, solar greenhouses, greenhouses, and cattle and sheep warm circles are promoted, making it the region with the highest solar energy application rate, application area and scale in China.
3 main problems
More than 900 million people in China live in rural areas,1200 million people have no electricity, and 15-8% people have no clean drinking water. About 40 million people live below the poverty line. Due to the shortage of fuel and other energy sources in rural areas, the utilization level is low, which leads to excessive deforestation, vegetation destruction and ecological environment deterioration, which seriously hinders rural economic and social development. Facing the pressure, the application of solar energy is slow and weak, and there are still some problems:
3. 1 Lack of understanding of the strategic significance of developing solar energy resources.
First, the development of solar energy has not been fully included in the government's agenda; Second, for a long time, solar energy projects did not have fixed funding channels like conventional energy construction projects or the existing funding channels were not smooth. Conceptually speaking, it is a lack of understanding of the significance of developing and popularizing solar energy to reduce or replace conventional energy and implement sustainable development strategy.
3.2 Lack of a complete incentive policy
Government support is the key to the development of solar energy and the initial driving force for the development of solar energy industry. At present, there is a lack of incentive policies that are conducive to the development of solar energy industry and stimulate residents to apply new energy equipment such as photovoltaic power supply devices.
3.3 Insufficient manpower input
Long-term planning, lack of financial support, the overall impact on solar energy entering the market is unpredictable. Some provinces, municipalities and autonomous regions implement special subsidies to support the promotion of solar energy, so that solar energy can be effectively promoted. However, due to too little and scattered investment, especially the key original devices such as photovoltaic cells, most of the manuscripts are imported, resulting in high solar energy costs and limited purchasing power of the people. The mature technology of solar energy is difficult to be popularized and applied to people without electricity as soon as possible.
4 solar energy promotion countermeasures
At present, various new and renewable energy sources developed and applied in China provide more than 300 million tons of standard coal every year, which plays an important role in promoting the development of national economy and meeting the energy needs of people in rural and remote areas. Due to the special geographical location, the majority of farmers and herdsmen in Tibet regard photovoltaic power supply system as a magic weapon that they have been looking forward to for many years, such as "lighting without oil and entertainment with programs". Solar photovoltaic system does have the potential to provide off-grid power for rural and remote areas, and its cost is lower than the cost of transporting fuel or extending transmission lines elsewhere. It is of great significance to develop and utilize new energy sources such as solar energy according to local conditions, transform them into high-grade electric energy, and provide power energy such as lighting, radio and television, communication and water pumps, so as to promote poverty alleviation, coordinate the development of economy and ecological environment and realize a well-off society. In order to further promote the application of solar photovoltaic power supply system, the following measures are suggested:
4. 1 Improve the application of solar energy.
The western region should strengthen the promotion of solar energy application, earnestly strengthen leadership, put the promotion and application of solar energy on the government's important agenda, take the promotion and application of solar energy as an important energy policy, incorporate it into the overall planning of national economic construction, and include it in the government's financial budget.
4.2 Increase investment and accelerate the application of solar energy.
The popularization and application of solar energy in the western region has great political and social effects. The development of solar energy is still in the primary stage, and the industry has not formed a scale, with low efficiency and no market competitiveness. The state should increase investment in solar energy application, ensure funds, and organize and arrange various models of photovoltaic power supply system application demonstration and photovoltaic power station construction.
4.3 Formulate preferential policies to promote industrial development
It is suggested that the government and local governments formulate preferential policies that combine tax reduction and exemption, price subsidies and incentives. By giving users a certain proportion of subsidies, farmers and herdsmen without electricity are encouraged to use photovoltaic power supply system to solve the problem of domestic electricity consumption, gradually guide the masses to change their concepts, overcome the idea of "equality and importance", improve their self-development awareness, accelerate the pace of solving the problem of users without electricity, and finally promote products to enter the market and gradually form local advantageous industries.
4.4 Expand exchanges and carry out international cooperation
Carry out international cooperation through multiple channels and forms, strive for more foreign funds and equipment to promote solar energy, make full use of the hot spots of international solar energy development today, earnestly seize the good opportunity of western development, take the initiative to attack, create conditions, further broaden the scope of cooperation, strengthen alliances, promote domestic and foreign associations, entrepreneurs and individuals to invest in the western region, and establish new energy entities. In conditional areas, based on the strategic idea of sustainable development, we will build megawatt solar photovoltaic power stations.
4.5 Long-term planning, comprehensive development and utilization
It is suggested that the government should make a long-term plan for solar energy promotion, implement the solar roof plan as soon as possible, and adopt various forms such as wind and light complementation, small hydropower and solar energy complementation, household photovoltaic power supply system, solar street lamp, solar energy and building combination, and combine independent systems with grid connection to comprehensively develop and apply solar energy. While continuing to do a good job in the implementation of the national bright project, wind plan, post and telecommunications and radio and television coverage plan, we will speed up the implementation of the light of science and Ali photoelectric plan in the western region.
Grassland does not forget the gospel of sunshine lifting water, and people are eager for the benefits of photovoltaic power generation. It is an inevitable choice for the western region in the new century and sustainable development to vigorously promote the application of solar energy and increase the proportion of new energy in the energy structure. Gradually change the living conditions of farmers and herdsmen who work at sunrise and rest at sunset, who are backward in science and technology, underdeveloped in economy, far from modern material civilization and almost isolated from the world. Getting them out of the "darkness" as soon as possible, using electric lights, watching TV and listening to radio, is conducive to social stability, national unity, economic development and social progress in the western region, shortening the distance from modern society and entering a new era.
European countries are opening up the road to sustainable energy, and the main factors affecting their decision-making are environmental protection, job creation and safe and reliable energy supply. Renewable energy technology has great advantages in these aspects. It has the least impact on the environment, can replace some conventional energy sources and increase the safety and reliability of energy supply; It needs a lot of equipment investment, creates more employment opportunities and contributes to economic growth. & lt/P & gt；
& ltP> In most parts of Europe, environmental factors have promoted the development of alternative energy technologies. Solar energy is recognized as an excellent alternative energy source, and its utilization is helpful to reduce carbon dioxide emissions and protect the environment. Many countries, such as Denmark, Finland, Germany and Switzerland, believe that climate warming is the main factor to promote solar energy research, development, display and sales activities. & lt/P & gt；
& ltP> In many countries, a noteworthy trend is to finance the development and commercialization of photoelectric technology. This reflects a general view that in the long run, the recovery rate of photovoltaic investment will be higher than that of active and passive solar thermal utilization technologies, and Belgium is an obvious example. & lt/P & gt；
& ltP> In many European countries, the focus of R&D has shifted to the solar energy industry and universities, and the government specially subsidizes those areas that domestic industries are interested in and specialized in, so that they can help create employment opportunities and foster economic growth points. & lt/P & gt；
& ltP> In many countries, it is difficult to implement the government incentive plan for solar energy technology due to the small government policy. But some countries still use incentives to promote the development of solar energy technology. In Austria, the federal, provincial and some places provide direct financial support and encouragement for solar installations; In Finland, companies can apply for government subsidies of up to 35% of the total cost of new solar installations, while families can apply for subsidies of 20%. & lt/P & gt；
& ltP> The Danish government's subsidy for installing solar water heaters is calculated according to the energy saving under standard conditions. At present, the subsidy is based on energy saving of 3 kronor (0? 52 dollars), equivalent to 10-30% of the total installation fee. Solar water heaters are quite popular in Denmark, and it is expected that there will be no need for subsidies after 2000. & lt/P & gt；
& ltP> also has other subsidies, such as financial assistance for public building renovation in Belgium and tax reduction and depreciation subsidies in Germany and other countries. & lt/P & gt；
& ltP> Although the price of traditional energy is low, the market of solar energy equipment continues to grow in many European countries. Although the number of solar energy companies has decreased, the companies that remain are often stronger and more resistant to market fluctuations. Privatization of power companies in some countries may increase their interest in bringing solar devices to market. In Austria and other countries, self-built solar collectors promote the development of active solar devices. & lt/P & gt；
& ltP> There are more than a dozen companies producing active solar heating devices in Denmark, and two of them have a large market share. Among them, Mars Solar Heating Factory (currently the largest manufacturer of flat solar heating devices in the world) provides district heating for 1250 households in Mars Town, Aeroe Island. The 8,000-square-meter solar collector array is connected with a 2 100 cubic meter hot water storage tank, and solar energy heating 100% can be used in June, July and August, which can meet the annual heat demand of the whole region. 5%。 Plans are being made to expand the heating plant in Mastar to meet most of the town's annual heating needs. Since 1987, the number of solar heating devices installed in Denmark has been increasing every year. In the late 1980s, only 2,300 solar heating devices were installed every year, and the number of solar collectors increased from 65,438 to 4,000 in 1996, accounting for about 40,000 square meters. Except a few Danish solar collectors are exported to Germany and Sweden, most of them are sold in China. & lt/P & gt；
& ltP> Norway has installed more than 70,000 small photovoltaic devices, with about 5,000 installed each year. Most of the equipment is used to supply power for holiday hotels in remote towns, mountainous areas and coastal areas. Typical equipment is usually 50-60 watts. & lt/P & gt；
& ltP> Finns also buy thousands of small photovoltaic devices (40- 100 watts) for summer homes every year. Neste, a national oil company, has a strong interest in further developing solar power generation, focusing on manufacturing thin-film photovoltaic modules, batteries and complete sets of equipment. & lt/P & gt；
& ltP> In addition, some countries have made efforts to commercialize products such as high-performance windows, solar water heaters, energy storage devices, transparent thermal insulation materials, solar lighting and photovoltaic devices combined with buildings. & lt/P & gt；
& ltP> European countries continue to be optimistic about passive solar energy technology. Some countries are committed to developing energy-saving windows with advanced transparent devices. France and Italy are developing transparent devices for electro-darkening. French researchers estimate that this technology can save up to 45% energy demand for the southern region every year. & lt/P & gt；
& ltP> French solar designers are replacing solar design principles with green design principles, that is, they should consider energy performance, application of safety materials, solar lighting, comfort and health of residents as a whole. This new design method will be used to design the office building of the French Environmental Protection and Energy Administration in Angers. & lt/P & gt；
& ltP> People are more and more interested in the combination of solar energy devices and photovoltaic devices with buildings. The Brundtland Center in Lund, tofte, Denmark is a 2,000-square-meter office and exhibition building, which has advanced daylight lighting system, including shutters installed on external windows to change the direction of light, reflective ceiling, light-transmitting windows facing south in the central attic and photovoltaic modules. & lt/P & gt；
& ltP> In Italy, research is being carried out to optimize the daylight lighting of buildings, such as improving the control system, adjusting natural and artificial light sources, improving the characteristics and efficiency of windows and sunshade devices, and improving the color efficiency of artificial light sources. & lt/P & gt；
& ltP> In many countries, consumers are increasingly interested in solar water heaters and have made great progress in technology and cost reduction. & lt/P & gt；
& ltP> Germany is continuing to implement its solar energy 2000 plan, which started in 1993. The purpose of this plan is to promote the solar-assisted central heating system used in large buildings. According to this plan, as many as 100 large-scale solar-assisted central heating systems will be installed in public buildings and monitored. The first such system has almost been completed. & lt/P & gt；
& ltP> Germany plans to launch an architectural competition to promote innovation in the combination of photovoltaic modules and buildings. Another task is to monitor 2200 photovoltaic systems installed on residential roofs. & lt/P & gt；
& ltP> According to the Joule Plan of the European Union, France, Spain and Germany are cooperating to build a new Mataro Library experimental building near Barcelona, which will be equipped with photovoltaic-thermal modules combined with the building.