The development process of solar energy utilization

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(1) The first stage, from 1615 to 1900
The history of modern solar energy utilization generally starts from the invention of the world’s first solar-powered pump in 1615 by French engineer Solomon de Cox. The main achievements of this stage are: In 1878, the Frenchman Pefson developed a printing press powered by solar energy. In 1883, the Swedish-American Eriksson made a solar-powered motorcycle, which can drive a 1.6-horsepower (1 horsepower=735.499W) reciprocating engine during the summer test. Almost all of these power devices use a condensing method to collect sunlight, the engine power is not large, and the working medium is mostly water vapor, which is expensive and has little practical value. In 1860, Frenchman Mouchau was ordered by the French emperor to develop the world’s first parabolic mirror solar cooker for use by the French army in Africa.

(2) The second stage, 1901~1920
This stage is the focus of solar energy research in the world, and it is still a solar power plant. However, the condensing methods used are diversified, and flat-plate collectors and low boiling point working fluids have been adopted. At the same time, the scale of the device has also been expanded. The output power of the largest one has reached 73.55kw. The practical value has increased, but the cost is still high. The main achievements worth mentioning at this stage are: In 1901 the United States built a solar pumping device in California, using a truncated cone concentrator that automatically tracks the sun, with a power of 7.36kw. From 1902 to 1908, Wells was in the United States. Five sets of dual-cycle solar engines were built, which are characterized by the use of low-boiling working fluids such as ammonia and acetylene and flat-plate collectors. In 1913, Schumann cooperated with Boyce to build a solar powered irrigation system composed of 5 parabolic trough mirrors each 62.5m long and 4m wide, south of Cairo, Egypt, with a total lighting area of ​​1250m2 and a power of 5.4 ×104w.

(3) The third stage, 1921-1945
Due to the massive exploitation and application of fossil fuels and the outbreak of the Second World War, the research and development of solar energy utilization is at a low ebb at this stage, and the number of people participating in research work, research projects and research funds have been greatly reduced.

(4) The fourth stage, 1946~1965
In the 20 years after the end of the Second World War, some people of insight began to notice the massive exploitation and utilization of oil and natural gas, and their resources will inevitably decrease. They only rely on fossil fuels with limited resources to meet the growing energy demand of mankind. It is not a long-term solution. We call on relevant parties to prepare early, find new energy sources, and attach importance to the research and development of solar energy. At this stage, research on the utilization of solar energy began to revive, strengthened the research on basic solar energy theory and basic materials, and achieved major breakthroughs in key technologies such as selective solar coatings and silicon solar cells; flat-plate collectors have made great progress. , The technology is gradually mature; the research of solar absorption air conditioner has made progress; a batch of experimental solar houses have been built; the technically difficult Stirling engine and solar thermal power generation technology have been preliminary researched. The main achievements and achievements are: In 1952, the French National Research Center built a solar furnace with a power of 50kw in the eastern part of the Pyrenees. In October 1954, the Applied Solar Energy Association was established in New Delhi, India, which is now the International Solar Energy Society (ISES), and then in December 1955, an international meeting with more than 30,000 representatives from 37 countries was held in the United States. Solar energy conferences and exhibitions. In 1954, Bell Labs in the United States successfully developed a practical silicon solar cell with a photoelectric conversion efficiency of 6%, which laid the foundation for the application of solar photovoltaic power generation technology. In 1955, Israel Taber and others put forward the basic theory of selective coating at the first international solar thermal science conference, and successfully developed practical selective coatings such as black nickel, which created conditions for the development of high-efficiency solar collectors. . In 1958, solar cells were first used in space and were equipped on the Pioneer 1 satellite of the United States. In 1960, Faber built the world’s first ammonia-water absorption solar air-conditioning system with a flat-plate collector in Florida, USA, with a cooling capacity of 5 tons. In 1961, a Stirling engine with a quartz window came out.

(5) The fifth stage, 1966~1973
At this stage, the world’s solar energy utilization has stagnated and the development is slow. The main reason is that the solar energy utilization technology is not yet mature and is still in the growth stage; the investment is huge, the effect is not good, and it is difficult to compete with conventional energy; the public, enterprises and The government’s attention and support.

(6) The sixth stage, 1973~1980
Since oil replaced coal in the world’s energy composition, it has become an important factor in the world economy and the survival and development of a country. The Middle East war that broke out in October 1973 forced the Organization of Petroleum Exporting Countries to use oil as a weapon to support the struggle of the people in the Middle East and safeguard the interests of the oil-producing countries. As a result, developed countries that rely on large quantities of cheap oil imported from the Middle East have suffered a heavy economic blow. As a result, some people in these Western countries exclaimed that the world has experienced an “oil crisis.” This crisis has objectively prompted people to realize that the current energy structure must be changed and that the transition to a new energy structure should be accelerated. Many countries, especially developed countries, have reinforced their support for solar energy and other renewable energy sources. Scope once again set off an upsurge in the development and utilization of solar energy. This stage is an unprecedented period of great development in the use of solar energy in the world, with the following characteristics.

① Various countries have strengthened the planning of solar energy research. Many countries have formulated short-term and long-term sunlight plans. The development and utilization of solar energy has become a government action, and support has been greatly strengthened. For example, in 1973, the United States formulated the National Solar Photovoltaic Power Generation Plan, and the solar energy research funding increased substantially, and the Solar Development Bank was established, which greatly promoted the commercialization of solar products. In 1974, Japan announced the “Sunshine Plan” formulated by the government. Research projects on the use of solar energy include solar houses, industrial solar systems, solar thermal power generation, solar cell production technology, decentralized and concentrated solar photovoltaic power generation systems, etc., and a lot of manpower has been invested. , Material and financial resources. At the same time, international cooperation is very active, and some developing countries have also begun to participate in the development and utilization of solar energy.

②The research field continues to expand, the research work is getting deeper and deeper, and a number of more important results have been achieved, such as compound parabolic mirror concentrating heat collector (CPC), vacuum heat collecting tube, amorphous silicon solar cell, solar thermal power generation, solar pool power generation , Photolysis of water to produce hydrogen, etc.

③Products such as solar water heaters and solar cells have begun to be commercialized, and the solar energy industry has been initially established, but the scale is small and the economic benefits are not yet satisfactory.

④ The solar energy development plans formulated by many countries at this stage have the problems of excessive requirements and urgency. They hope to replace fossil energy in a relatively short period of time and realize the large-scale utilization of solar energy. However, the problems and difficulties encountered in the implementation process Underestimated. For example, the United States plans to build a small solar demonstration satellite power station in 1985 and a 5 million kilowatt space solar power station in 1995 are such projects. Later, due to funding and other reasons, it had to be adjusted. So far, the space solar power station has not been launched.

This worldwide upsurge of solar energy development and utilization has also had a significant impact on China and promoted the development of China’s solar energy development and utilization work. Some far-sighted scientific and technical personnel have devoted themselves to the solar energy industry and actively put forward suggestions to the relevant government departments, published books and magazines, and introduced foreign solar energy utilization trends and technologies. The promotion and application of solar energy has developed rapidly. Solar cookers have been promoted in rural areas, solar water heaters have been developed and applied in cities, and solar cells used in space have been applied to the ground. In 1975, the relevant state departments held the “First National Solar Energy Utilization Experience Exchange Meeting” in Anyang, Henan Province, which greatly promoted the development of China’s solar energy industry. After the meeting, solar energy research and promotion work was incorporated into the national plan, and special funds and special supplies of shortage materials were supported; some colleges and universities and scientific research institutes have set up solar energy research rooms or research groups, and in some places, they have begun to prepare for the establishment of solar energy research institutes. . In 1979, the State Economic Commission and the National Science and Technology Commission held the “Second National Solar Energy Utilization Experience Exchange Meeting” in Xi’an, formulated a national development plan for solar energy utilization, established the Chinese Solar Energy Society, and further promoted the development of China’s solar energy industry.

(7) The seventh stage, 1981~1991
The upsurge of solar energy development and utilization that started in the 1970s began to ebb shortly after entering the 1980s, and gradually entered a trough. Many countries have drastically reduced solar energy research funds one after another, of which the United States is the most prominent. The main reasons for this situation are: the world oil prices have fallen sharply, while the prices of solar energy products remain high and lack competitiveness; there is no major breakthrough in solar energy utilization technology, and the goals of improving efficiency and reducing costs have not been achieved, which has shaken some countries. And some people have confidence in the development and utilization of solar energy; nuclear power has developed rapidly, which has restrained the development of solar energy utilization to a certain extent. Although research funding has been drastically reduced, there are still some research projects at this stage that have not been interrupted and good progress has been made. For example, from 1981 to 1991, more than 20 solar thermal power stations with a capacity of 500kw or more were built in the world. Among them, 9 trough solar thermal power stations were built in the California desert from 1985 to 1991, with a total installed capacity of 353.8MW. ; In 1983, the United States built a 1MW photovoltaic power station, followed by a 6.5MW photovoltaic power station in 1986.

(8) The eighth stage, 1992-2000
The massive consumption of fossil energy has caused global environmental pollution and ecological damage, posing a serious threat to human survival and development. In this context, the United Nations convened the “World Conference on Environment and Development” in Brazil in June 1992. The conference adopted the “Rio de Janeiro Declaration on Environment and Development”, “Agenda 21”, “Framework Convention on Climate Change” and “About A series of important documents such as the “Declaration of Principles on Forest Issues” have closely integrated environment and development and established a model for economic and social development on the road of sustainable development. After the conference, countries around the world have strengthened the research and development of clean energy technologies, closely integrating the use of solar energy with environmental protection, so that the development and utilization of solar energy has come out of the trough, and gradually gained attention and strengthened. In 1996, the United Nations held the “World Solar Energy Summit” in Harare, the capital of Zimbabwe. At the meeting, the “World Solar Energy 10-year Action Plan (1996~2005)”, “International Solar Energy Convention”, “World Solar Energy Strategic Plan” were discussed. An important document, the “Harare Solar Energy and Sustainable Development Declaration” was issued after the meeting. This meeting further demonstrated the firm determination and confidence of the United Nations and other countries in the world to develop the use of solar energy, and called on the world to take joint action to widely develop the use of solar energy. After the World Conference on Environment and Development, the Chinese government attached great importance to the environment and development, and placed great emphasis on the development of new and renewable energy sources such as solar energy. In August 1992, the State Council approved the “Ten Major Countermeasures for China’s Environmental Development” and clearly stated that ” Develop and promote clean energy such as solar energy, wind energy, geothermal energy, tidal energy, biomass energy, etc. according to local conditions”; in March 1994, the “China Agenda 21-China’s 21st Century Population, Environment and Development White Paper” was released, highlighting: ” Renewable energy is the foundation of the future energy structure”, it is necessary to “put the development of renewable energy in the priority position of the national energy development strategy”, “extensively carry out energy conservation and actively develop new and renewable energy”, in 1995, the State Planning Commission, The State Science and Technology Commission and the State Economic and Trade Commission formulated and issued the “New Energy and Renewable Energy Development Outline (1996~2010)”, which put forward the development goals, tasks and corresponding policies and policies of China’s new energy and renewable energy from 1996 to 2010. measure. In August 2000, the State Economic and Trade Commission formulated and issued the “Main Points of the Development Plan for New Energy and Renewable Energy Industries from 2000 to 2015”, which put forward the tasks, goals, and related policies and methods for the construction of China’s new energy and renewable energy industries. measure. All of these have played an important role in promoting the faster, better and healthier development of China’s solar industry. Generally speaking, after 1992, the world’s solar energy utilization has entered a new stage of rapid development.

(9) The ninth stage, from 2001 to present
The first decade of the 21st century has the following main characteristics.
①The development and utilization of solar energy is closely integrated with the world’s sustainable development and ecological environmental protection, and the world is acting together to realize the development strategy of new energy and renewable energy such as solar energy in the world.

②The development goals are clear, the key points are prominent, and the measures are effective. Many countries have successively formulated and issued a series of laws and regulations, guidelines, policies, action plans and roadmaps to promote the development of solar energy and other new and renewable energy sources.

③While increasing research and development efforts, pay great attention to transforming research results into products, continuously expand the application fields and application scales of new energy and renewable energy such as solar energy, strive to reduce costs, greatly increase economic benefits, and actively develop new technologies such as solar energy utilization. Industry, accelerate the process of industrialized production and commercial application.

In just ten years, many remarkable achievements and progress have been made.
① The United States, Germany, Spain, Japan, Italy, Canada, the United Kingdom, Australia and other developed countries, as well as developing countries such as China, India, and Brazil, have successively formulated and implemented the Renewable Energy Law and its supporting plans and measures, and vigorously Promoting the R&D, production, industrial construction and commercial application of new and renewable energy sources has resulted in fruitful results and a gratifying situation. For example, Germany has formulated and revised the Renewable Energy Law three times since 2001, and has taken effective measures to vigorously implement it, so that the proportion of renewable energy in the total primary energy consumption has increased, from only 2.1% in 1998. By 2008, it had increased to 7.1%. For example, China promulgated the Renewable Energy Law in 2005 and took effect on January 1, 2006; in 2009, it solemnly promised to the international community that by 2020, the proportion of non-fossil energy in the country’s total primary energy consumption will reach 15%, per unit of GDP. Emissions decreased by 40%~45% compared to 2005; in August 2007, the “China’s Renewable Energy Mid- and Long-term Plan (2010~2020)) was released; in March 2008, the “China Renewable Energy “Eleventh Five-Year Plan” was released Planning (2006~2010)); September 18-21, 2007, the World Solar Energy Conference was held in Beijing, China.

②The industrial production and commercial application of new energy and renewable energy such as solar energy in the world are developing rapidly. According to the “2011 World Energy Statistics Report” released by BP on June 8, 2011: Renewable energy accounted for 1.8% of global energy consumption in 2010, and total world renewable energy consumption excluding hydropower was 158.6 hundred. Million tons of oil equivalent, of which: the United States is 39.1 million tons of oil equivalent, accounting for 24.7%; Germany is 18.6 million tons of oil equivalent, accounting for 11.7%; Spain is 12.4 million tons of oil equivalent, accounting for 7.8%; China is 12.1 million tons of oil equivalent 10,000 tons of oil equivalent, accounting for 7.6% (excluding statistics for Hong Kong, Macau, and Taiwan). By the end of 2010, the total installed capacity of wind power in the world reached 199.520GW, of which: China was 44.78GW, accounting for 22.4%; the United States was 40.274GW, accounting for 20.2%, Germany was 27.364GW, accounting for 13.7%; Spain was 20.3GW, accounting for 10.2 %; India is 12.966Gw, accounting for 6.5%. By the end of 2010, the global total capacity of geothermal power generation equipment reached 10,751MW, and the total capacity of geothermal direct utilization equipment reached 50,583MW. By the end of 2009, the total output of solar water heaters in the world reached 53.85 million square meters. Cumulative holdings reached 270 million square meters. In 2002, China launched a “bright project” of “sending electricity to the countryside” that was amazing to the world. After several years of construction, by the end of 2005, a total of seven provinces, The autonomous region has built 268 small hydropower stations, 721 photovoltaic power stations and solar/wind hybrid power stations, with a total investment of 4.7 billion yuan, and solved the major problem of basic electricity consumption for 300,000 farmers and livestock households and a total of 1.3 million people without electricity. China’s biogas utilization is well-known in the world. By the end of 2010, a total of 73,017 large, medium and small biogas projects have been constructed (including 4,963 large, 22,795 medium, and 45,259 small), 191,600 domestic sewage biogas projects, and rural households. There are 38.5 million biogas digesters, benefiting more than 40 million households and about 150 million people. The annual output of biogas reaches 14.26 billion cubic meters, which can replace about 25 million tons of standard coal and reduce CO2 emissions by about 50 million tons.

③The rapid development of solar energy buildings. The energy consumption of buildings accounts for about 35% to 40% of the world’s total energy consumption. It can be said that seizing it will capture the world’s energy saving and emission reduction “bull nose”. Solar buildings mainly include passive solar buildings, active solar buildings and “zero energy buildings” (see color picture 1). As early as the 1930s, the United States began research and experiments on solar houses, and successively built a number of experimental solar houses; in the 1970s, some industrially developed countries included solar houses in their research plans. By the end of the 1980s, the world had completed There are more than tens of thousands of solar houses; from the middle of the 20th century to the beginning of the 21st century, the world has a “solar roof” fever. The United States, Japan, Germany, Spain, etc. have successively proposed “100,000 roofs”, “million roofs” and even ” In the “ten million roofs” plan, China has proposed the use of building roofs to actively develop the direction of “user-side distributed photovoltaic power generation”, pushing solar buildings to a new stage. In the second decade of the 21st century that has just begun, the momentum of development is even more gratifying. By the end of 2012, the cumulative installed capacity of global photovoltaic power generation reached 101.271GW. As of the end of 2012, the cumulative installed capacity of solar photovoltaic power generation in Germany reached 32.278Gw, ranking first in the world. The utilization of solar energy in China is developing rapidly. By the end of 2012, the cumulative installed capacity of photovoltaic power generation reached 7GW; by the end of 2011, the number of solar water heaters in operation nationwide reached 193.6 million square meters, ranking first in the world, and could replace about 29 million tons per year. Coal; By the end of 2010, a total of 20 million square meters of solar houses had been built across the country. Since 2011~2013, the Chinese government has formulated plans, issued guidelines and policies, formulated and implemented measures to vigorously develop solar energy utilization, and do everything possible to open up the domestic application market, which has become a highlight of the global development of new energy and renewable energy. China proposes that by 2015, the total installed capacity of solar power will reach 35 million kilowatts, and the cumulative solar thermal utilization area will reach 400 million square meters; by 2020, the total installed capacity of solar power will reach 50 million kilowatts, and the cumulative solar thermal utilization will be The thermal area reaches 800 million square meters.

It can be seen from the above development history that the development of solar energy utilization has not been smooth sailing. There are high tides and low tides, and it is constantly advancing while overcoming various obstacles and difficulties. However, because it is a renewable energy with unlimited resources and a clean energy that is in harmony with the ecological environment, it has an infinitely bright future and will gradually develop into one of the important members of the future energy composition of mankind.