Abstract The status of photovoltaic power generation in the polysilicon industry has been steadily increasing. In 2012, the global installed capacity of new PV was 32 GW, the global installed capacity reached 100 GW, and the total installed capacity in Germany was 32 GW, ranking first. In the first half of 2011, Germany’s total renewable energy generation was...
Polysilicon industry background

The status of photovoltaic power generation has steadily increased the global installed capacity of 32 GW in 2012. The cumulative installed capacity in the world has reached 100 GW, and the total installed capacity in Germany is 32 GW, ranking first. In the first half of 2011, Germany's total renewable energy generation achieved a historical breakthrough, reaching 28% of its electricity demand. Photovoltaic power generation surpassed hydropower for the first time, accounting for 3.5% of total electricity demand. With the occurrence of the nuclear accident in Fukushima, Japan and the intensification of smog in China this spring, people are increasingly looking for clean and efficient new energy. Here, solar photovoltaic power generation has become one of the most concerned focuses. In 2013, global installations are expected to reach 35 GW. The continuous growth of photovoltaic installed capacity worldwide indicates that the status of photovoltaic power generation will steadily increase.

Polysilicon industry concentration increase polysilicon is the basic raw material of information industry and solar photovoltaic power generation industry. Many countries have listed it as a strategic material, implementing policy encouragement and financial support. However, due to the lack of polysilicon industrialized production technology, domestic demand is long-term. Dependent on imports. Until 2005, Luoyang Zhongsi High-Tech Co., Ltd. relied on China Enfei Engineering Technology Co., Ltd. to build China's first industrialization demonstration line, completely breaking the foreign years of technical blockade and market monopoly.


In recent years, China's polysilicon industry has developed at a high speed and achieved large-scale supply. In 2011, China's polysilicon production reached 82,000 tons, ranking first in the world, initially solving the domestic polysilicon supply bottleneck problem and laying the foundation for the development of the photovoltaic industry. By the end of 2012, China's polysilicon nominal capacity was about 180,000 tons/year, and domestic consumption was 143,000 tons in 2012. If the downstream enterprises' production capacity is fully released, they will consume more than 200,000 tons of polysilicon.

The commercialization of photovoltaic power generation will continue to reduce the cost of polysilicon production. At the current stage, when polysilicon technology has not yet made a revolutionary breakthrough, one of the simple and clear criteria for the survival of polysilicon enterprises will be It is the gap between production costs and world-class companies.

In foreign countries, polysilicon belongs to an industry with a very high concentration of industry. In the past 30 years, there are only 7 polysilicon production enterprises with a certain scale in the world, and a total of 10 factories are concentrated in the United States and Japan. In China, the “high price market” that has appeared in the polysilicon industry has caused many companies driven by capital profit-seeking to take risks and get involved in the polysilicon industry. However, due to the lack of core technology and management improvement capabilities, it is difficult to form a continuous cost reduction capability. In 2010, some enterprises had intermittent production; since 2011, most of the enterprises have been discontinued.

The harsh market baptism has been eliminated, and most of the enterprises with no scale effect and some backward production capacity of large-scale enterprises will be eliminated, which will definitely increase the industrial concentration. Effective polysilicon production capacity is a production that can form a sustainable market supply capacity and has an internationally competitive production cost. At present, the capacity of this part of China is less than 100,000 tons/year, and the number of enterprises capable of providing effective production capacity is about 3.8.

Polysilicon industry safety has been reduced for many years, China's photovoltaic polysilicon is more than 50% dependent on imports, and electronic grade polysilicon is 100% dependent on imports. At present, China's polysilicon industry is deeply mired in the three major pressures of economic crisis, trade war and currency war. Coupled with the misleading foreign media, China's polysilicon has been struggling under the circumstance of “high energy consumption and high emissions”: various preferential policies have been cancelled. Electricity price concessions are difficult to obtain and financing channels are blocked. The US and European polysilicon enterprises, in the context of government policy support, financial subsidies and high-priced long-term single-bundling Chinese downstream customers, dumped the Chinese market at a very low price, which caused a fatal blow to the emerging Chinese polysilicon industry.

At present, 80% of China's polysilicon enterprises have stopped production for more than one year. In 2012, China's capacity utilization rate was only one-third. In the first quarter of 2013, the national production was less than 10,000 tons, and the capacity utilization rate was less than 25%. With the increase in the demand for steel in the photovoltaic industry, the supply capacity of China's polysilicon products has not significantly increased, and internal and external problems have led to a decline in the industrial safety of China's polysilicon industry.

Since 2009, the external dependence of China's polysilicon products has remained at around 50% and remains high. Relying on a large number of polysilicon imports to support the development of China's photovoltaic and information industry.

In 2012, China's polysilicon production accounted for a quarter of the world. The suspension of production of domestic polysilicon enterprises will lead to an imbalance between global supply and demand of polysilicon. Chinese PV companies will also face a situation in which raw material supply prices rise and production costs increase substantially. It can be said that it is the "shield" of polysilicon that not only stabilizes the import price of foreign polysilicon products, but also provides a "protective umbrella" for the Chinese photovoltaic industry to provide breathing and development. Therefore, China's polysilicon and China's photovoltaic industry share the glory and shame, and the behavior of brothers and walls between any different links in the industry chain is not conducive to the development of China's photovoltaic industry.

Polysilicon energy consumption analysis

Photovoltaic power generation is different from coal-fired power generation in thermal power plants. Photovoltaic power uses the photovoltaic effect of the semiconductor interface to convert solar energy directly into electrical energy. Although polysilicon needs energy consumption in the production process, it can generate more energy as the core material of solar photovoltaic power generation. Therefore, in terms of energy return rate or energy regeneration ratio, polysilicon and general industrial products are very different.

According to calculations, photovoltaic power generation starts from silica smelting, and after industrial silicon, polysilicon, ingot (drawing) slicing, cell manufacturing, photovoltaic module production, and photovoltaic system installation, the total energy consumption of the entire industrial chain is 1.60 kWh/W. .

The specific electricity consumption of each link is: (1) Energy consumption of “silica sand – metallurgical silicon”: 13 kWh/kg; (2) Energy consumption of “metallurgical silicon – polysilicon”: 120 kWh/kg, steam consumption 50 kg / kg - silicon; 1.35 kg of metallurgical silicon per 1 kg of high-purity polysilicon; (3) "polysilicon - polycrystalline silicon" energy consumption of 30 kWh / kg; 1 kg of silicon ingot / silicon rod requires 1.1 kg high Pure polysilicon, 1 kg silicon rod or silicon ingot can cut 46 pieces of 156 × 156 mm silicon wafers, each of which produces an average of 4.2 watts of solar cells; (4) "polycrystalline silicon wafers - polycrystalline silicon photovoltaic cells" energy consumption of 0.2 kWh / watt , 5.7 g / watt of high-purity polysilicon required to manufacture solar cells per watt; (5) energy consumption of "photovoltaic cells - photovoltaic modules" of 0.15 kWh / watt, (6) energy consumption of "photovoltaic modules - photovoltaic systems" 0.25 kWh / watt.

Calculated by the above coefficients, the total energy consumption result is: 1.55 kWh / watt, solar cell module yield = 97% (ie package yield), total energy consumption: 1.55 / 0.97 = 1.60 kWh / watt.

According to the regional classification of the National Development and Reform Commission's February 2013 “Notice on Improving the Photovoltaic Power Price Policy Notice”, calculate the power generation and energy recovery period in representative areas:

The second category: 1 watt battery installed in the northwest region, the average annual effective power generation hours 1400-2100 hours, calculated according to the annual equivalent hours 1500 hours, the average annual power generation 1.5 kWh; according to the life cycle of 25 years, the total power generation At 37.5 kWh, the energy regeneration ratio is 37.5/1.6=23.4, that is, 1 kWh of electricity can be regenerated 23.4 kWh; the energy recovery period is 1.07 years (= power consumption/annual electricity generation).

After calculation, the energy recovery period of photovoltaic power generation in different regions, the energy recovery period of crystalline silicon solar cells is between 1.07 and 1.6 years, and the average energy recovery period is 1.3 years. It can be foreseen that with the advancement of technology in the industry, the energy consumption of each link will still decline, and the energy recovery period of photovoltaic power generation will be shortened to less than one year.

At present, the domestic silicon crystal solar module has a service life of 25 years. After the energy consumption of the solar module is recovered, it can generate electricity with almost no energy consumption, and there is no pollutant emission during the whole life. In fact, even after 25 years, the power generation efficiency of solar modules is about 80% of that of 25 years ago. It can still be used for a long time, and there have been cases where crystalline silicon solar energy has been used for more than 30 years.

Comparison of standard coal consumption According to the "China Power Reduction Research" released data: in 2012, the average power supply standard coal consumption of more than 60 million thermal power units nationwide was 324 grams of standard coal / kWh. The total energy consumption of photovoltaic power generation from silica to the system is 1.60 kWh/W, and the total energy consumption is 518.4 g standard coal/Wp. The crystal silicon solar cell has a life of 25 years and is basically maintenance-free. The average power generation is calculated according to the annual effective power generation time of 1500 hours. The average power generation is 37.5 kWh. The standard coal is 13.82 g of standard coal/kWh, which is only coal consumption. 4%, although low in power generation, is indeed a good source of energy.

Energy balance analysis of the whole industry According to statistics, according to the domestic production of polysilicon of 644,000 tons in 2012 and 120 kilowatt-hours of electricity consumption per kilogram of polysilicon, the total electricity consumption of polysilicon production is 7.68 billion kWh, accounting for only 4.9591 billion yuan of total electricity consumption in 2012. The 0.1548% of kWh is negligible, and the name “high energy consumption” is not true.

The 64,000 tons of polysilicon can produce 10.83 GW of solar cells. The second type of area generates 16.25 billion kWh of electricity per year, and 48% of the annual power generation is enough to repay the polysilicon power consumption. With the increase of polysilicon technology, the energy consumption is reduced (from 120 kWh/kg to less than 100 kWh/kg), the efficiency of photovoltaic cells continues to increase (17.5-22%), and the substrate continues to be thinned. The energy regeneration ratio of the power generation system is likely to be higher. According to the calculation results, it is entirely possible to use photovoltaic power generation to produce photovoltaic products such as polysilicon, and to realize a benign and sustainable solar energy industry.

Polysilicon cleaning production roadmap

After the polysilicon process is improved, it is fully capable of achieving clean production. In the initial stage of industrial development, the production scale is small, the by-product processing technology is imperfect, and some by-products of silicon tetrachloride have a negative impact on the industry through simple treatment methods such as hydrolysis and storage.

With the expansion of the scale of the industry, the simple by-product treatment method can no longer meet the needs of large-scale production. In order to reduce production costs and achieve safe and environmentally friendly production, enterprises represented by China Silicon High-Tech Co., Ltd. have thoroughly studied silicon tetrachloride hydrogenation technology and converted it into The raw material trichlorosilane realizes the closed circuit of the polysilicon production system, thereby reducing the production cost of polysilicon.

Public opinion misleading In 2007, China became the world's first largest producer of photovoltaic products for the first time. In that year, the output of polysilicon was 1,130 tons, exceeding the thousand-ton mark. The output of China Silicon High-tech was 506 tons, accounting for 50% of the country, ranking first, becoming the focus of attention outside the industry. .

In August 2007, a domestic journal published "The Truth of Solar Energy Industry". On March 9, 2008, a well-known American media quoted the main point of the article, and published a speech entitled "Chinese solar energy manufacturers dump industrial waste in the factory". It is reported that a sporadic valve leakage incident in the debugging process of the Silicon High-tech 300-ton production line in Daxie's rendering caused misunderstandings by those who did not understand the inside story of the polysilicon industry. The voice of "condemning polysilicon" is endless. This report is still one of the "basis" to prove polysilicon pollution.

In response to this report, the Ministry of Environmental Protection has repeatedly and randomly visited the site, and the local environmental protection department also conducted a two-week on-site surprise test, which finally concluded that “the middle silicon high-tech “three wastes” all meet the standard discharge”. In 2009, China Silicon High-Tech won the National “Outstanding Contribution Award for Environmental Protection” and in 2010 won the “National Environmental Excellent Brand Enterprise”.

Strict verification and objective conclusions have been the name of China's polysilicon enterprises. It is on this basis that in 2012, “polysilicon energy-saving and environmental protection new technology, equipment and industrialization” won the second prize of National Science and Technology Progress Award, the highest award in the industry. Become a landmark event in the development of the industry.

Treatment of polysilicon by-products Reports on polysilicon contamination are mainly focused on the treatment of silicon tetrachloride. The US media issued a statement that "silicon tetrachloride will fall into the ground and will not grow." In fact, silicon tetrachloride is not only a major by-product of polysilicon production, but also one of the main sources of polysilicon production materials. In recent years, with the development and promotion of technologies such as silicon tetrachloride cold hydrogenation, it has realized the hydrogenation of 95% of by-product silicon tetrachloride produced in the production process of polysilicon into trichlorosilane raw materials, and the remaining about 5% The impurity silicon tetrachloride is purified and used to produce gas phase white carbon black or other silicone products. The material is recycled in a closed state, which not only effectively solves the problem of by-product processing, but also reduces the production cost and eliminates the tetrachlorination. Silicon pollution hazard.

Polysilicon "three wastes" treatment measures In fact, the "three wastes" of polysilicon production are simple and easy to handle. The polysilicon reduction tail gas mainly contains hydrogen, hydrogen chloride, trichlorosilane, silicon tetrachloride and other components; the waste water is exhaust gas elution water, pure water to prepare drainage, etc., containing hydrochloric acid, is acidic; the waste residue is silicon powder, silicon dioxide, limestone Slag, etc., harmless, insoluble, is a general solid waste.

The exhaust gas is rinsed with water or alkaline water, and the main components in the exhaust gas are hydrolyzed into silica and hydrochloric acid by using the principle that the chlorosilane is easily hydrolyzed and neutralized by acid and alkali, and the hydrochloric acid reacts with the alkali to form neutral water, further After treatment, it is discharged to the standard; silica is solidified by pressure filtration and transported to the government designated dump site or paved for paving.

The breakthrough in hydrogenation technology is the basis for the formation of closed loops in the production process of polysilicon. At present, most domestic factories of 1,000 tons have “exhaust gas recovery” system, and the environmental impact assessment and monitoring system is perfect, and there is no “high emission”.

Comparative analysis of polysilicon production process

At present, the international popular and mass-produced polysilicon production process is mainly divided into two categories, namely, the improved Siemens method and the silane method. The improved Siemens method has a broad application base and has occupied a major position in the current expansion of polysilicon capacity. In recent years, when the whole industry is in trouble, some domestic enterprises have turned their attention to the more unfamiliar silane polysilicon production process. Is the Siemens method or the silane method superior or worse?

Historical origin In 1955, Siemens Germany developed a production process for the reduction of high-purity trichlorosilane by hydrogen and the deposition of polycrystalline silicon on a silicon core heated to about 1100 °C. In 1957, this polysilicon production process began to be applied to industrial production. It is called "Siemens Law". Since then, each company has improved the Siemens method according to its own characteristics and formed their own improved Siemens process.

The silane method for the production of polycrystalline silicon is also a chemical method. The core process is to thermally decompose high-purity silicon into high-purity silane in the reactor to produce rod-shaped and granular products. Currently, the US MEMC company and the Norwegian REC company use the silane method to produce polysilicon.

Historical performance In recent years, the production and share of different methods of polysilicon production are shown in Table 4: As can be seen from Table 4, the silane method polysilicon production share is about 11%. Since 2007, a total of four companies in China have introduced, researched, developed and industrialized silane polysilicon technology. The largest investment is 2.3 billion yuan, with an annual output of 3,000 tons of polysilicon.

Foreign polysilicon industry policy

US polysilicon policy For many years, the US and US polysilicon production has been in the forefront of the world. The government has included the polysilicon industry in the clean energy and manufacturing regression, through investment subsidies, fiscal and tax support, basic measures construction subsidies, electricity price subsidies, land concessions, etc. Policies, support and subsidize polysilicon enterprises. In 2010 alone, the US government provided “investment subsidies” to polysilicon enterprises with a policy support of up to 462 million US dollars; Hemlock received US government subsidies totaling 746 million US dollars in 2008-2011, about It accounts for 5% of Hemlock's total revenue from 2008 to 2011.

German Polysilicon Policy The German government provides various forms of financial support for polysilicon companies. As of the end of 2011, various investment subsidies provided by German government agencies saved WACKER a cost of 447 million euros.

In the case of the rise of the new energy industry, which led to a sharp increase in demand for polysilicon, the foreign polysilicon enterprises rarely expanded their production in 2005-2007. After 2008, the capacity expansion of foreign polysilicon enterprises has been almost simultaneous with the government's huge subsidies. It can be said that it is because of the government's support that it has led to the competitive advantage of foreign polysilicon enterprises. To a certain extent, this kind of advantage has formed for China. The real pressure of polysilicon companies.

Policy advice for the polysilicon industry

According to the National Energy Administration's plan, by 2050, China's total electricity consumption will be 1.13 billion kWh, the proportion of renewable energy will reach 62%, the proportion of solar photovoltaics will be 12.4%, and the total installed PV will reach 1000 GW. Facing such a broad domestic demand market, protecting the stability and development of the polysilicon industry from the policy level is conducive to promoting the healthy development of China's photovoltaic industry.

Supporting and supporting the strong, supporting advanced polysilicon enterprises to develop new products polysilicon policy should adapt to objective changes, encourage superior enterprises to energy-saving technological transformation, and further enhance competitiveness. The Ministry of Science and Technology supported the research of 24 pairs of energy-saving reduction furnaces during the 10th Five-Year Plan period. The 11th and 12th Five-Year Plan supported cold hydrogenation, thermal hydrogenation, energy-saving and high-efficiency purification technologies and comprehensive utilization technologies of by-products. The polysilicon industry has played a huge role in promoting, but compared with more than 5,000 polysilicon industrial chain technologies and products owned by WACKER in Germany, China's polysilicon enterprises have single products and poor anti-risk capabilities, which require further support from the state and increased investment in science and technology. Improve the technical level, improve quality, stabilize quality, reduce consumption, improve comprehensive utilization capacity, and implement diversified product development (such as silicone, fiber silicon tetrachloride, silane, etc.) to ensure industrial safety.

The open photovoltaic power generation market and the direct trading of photovoltaic power generation pilot photovoltaic power generation are gold power, and its power generation season and power generation period are basically consistent with the peak power consumption. At present, the cost of photovoltaic power generation in China already has a certain commercial application base, the cost is about 1 yuan / kWh, and the peak electricity price is different in different parts of the country.

Photovoltaic power generation will be conducive to peaking of the power grid under the condition of matching with peak power. If the photovoltaic power generation market is opened in these areas, allowing direct trading between general industrial and commercial enterprises and photovoltaic power generation, it will effectively promote photovoltaic power generation applications.

Creating a Fair Competition Environment In the current global economic downturn and the prevalence of trade protection, polysilicon and photovoltaics have become the focus of global attention. Governments have extended their “tangible hands” and adopted various measures to protect local enterprises: US polysilicon enterprises The price of electricity is 2-3 cents/kWh, Japan's Deshan Caoda and Germany's Wacker have their own power stations, and the price of Korean polysilicon enterprises is equivalent to RMB 0.41/kWh.

China's polysilicon enterprises basically use the highest price of their peers in the world. In order to prevent China's polysilicon enterprises from "starving to death before the meal", and in view of the fact that the total consumption of the whole industry accounts for the small total electricity consumption of the whole society, the polysilicon enterprises should be directly purchased and self-supplied. Such policies have created equal conditions for polysilicon enterprises to participate in international competition.

At present, China's photovoltaic industry is attracting attention because of “double reverse”, and polysilicon is the foundation of the photovoltaic industry. Through nearly ten years of hard work, polysilicon production, research and research have achieved historical breakthroughs in all aspects, but also led to the rapid development of the photovoltaic industry. In the period of low industry, we should overcome the temporary difficulties with a hard-working spirit of hard work, and meet the bright future of photovoltaics with better performance.

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