This article is from: Science and Technology Daily

Science and Technology Daily reporter Li He

Data released by the National Energy Administration show that in the first half of 2022, the country's renewable energy generation reached 1.25 trillion KWH, of which solar power generation increased by 13.5 percent. Solar photovoltaic industry, from the "three heads outside", subject to people's distress, to firmly occupy the world's top photovoltaic industry, become the new era of China's business card, China's photovoltaic industry only took less than 10 years. Among them, scientific and technological innovation is an important force that cannot be ignored.

Ten years of hard work: from being controlled by others to leading the world

Time pulled back to 2012, the newly emerged Chinese photovoltaic industry, facing Europe and the United States "double reverse" stick. At that time, raw materials, markets, and core technologies were all subject to the Chinese photovoltaic industry ushered in a "storm", and the photovoltaic industry fell to the bottom.

What to do? Relevant national authorities and photovoltaic companies began to realize that the core technology and industrial chain, supply chain "life door" must be firmly in their own hands. China's photovoltaic industry has opened a ten-year road.

On the one hand, the government has introduced relevant industrial policies, electricity subsidies, leader plans, household photovoltaic, green certificate transactions and other policies have appeared, from capital to the market, from finance and taxation to land, to create a policy environment conducive to the development of domestic industries, paving the way for industrial development and growth. On the other hand, Chinese photovoltaic companies have also "learned the pain", setting off another round of scientific and technological innovation boom. Longi, Jinko, Tongwei, GCL and other enterprises continue to increase investment in scientific and technological innovation.

Taking the module end equipment string welding machine as an example, before 2013, the string welding machines purchased by Chinese photovoltaic factories were basically from Germany, the United States, Spain and Japan.

Just three years later, the market landscape is very different. Under the attack of Otway, Lead Intelligence and other domestic string welding machine enterprises, 95% of the string welding machines in the new production line in the Chinese market have become domestic equipment. According to the data of the China Photovoltaic Industry Association, by the end of 2015, the four core links of photovoltaic manufacturing, that is, polysilicon, silicon wafers, cells and modules, the output of domestic enterprises ranked first in the world, accounting for 48.5%, 79.6%, 62.6% and 76.1% of global output.

At the same time, China has also mastered the 10,000 tons of improved Siemens method polysilicon production process, and the fluidized-bed polysilicon production technology has also begun to be industrialized. The industrialization efficiency of monocrystalline and polycrystalline cells reached 19.5% and 18.3%, respectively, which is in the world's leading level. In terms of special equipment for the production line, from silicon material production, silicon wafer processing, battery and module production to testing equipment and simulators related to the photovoltaic industry chain, we have complete sets of supply capabilities, and even some products have been exported to different degrees.

Ten years of innovation: cost reduction and efficiency throughout

Throughout the process of photovoltaic cost reduction and efficiency, technological innovation to promote the industry cost reduction and efficiency throughout, which is the choice made by the market.

In the past ten years, many links in the photovoltaic industry have set off a "route dispute", from crystalline silicon to thin film, from polycrystalline to single crystal, from centralized to cluster inverter... But the fundamental of these competitions is to reduce costs and increase efficiency, improve the economy and competitiveness of photovoltaic energy, among which the improvement of battery conversion efficiency plays a key role in the overall transformation and upgrading of the photovoltaic industry "main track".

Turn back the clock to 2015. This year, with the strong support of national policies, the photovoltaic industry ushered in a golden development period. Photovoltaic companies out of the trough, according to market demand, around the two aspects of performance and cost, continue to promote technology upgrades.

During this period, the market demand and technology development line were still dominated by polycrystal, and under the technological research of JA, Jinko, TRW, Artes and other first-line manufacturers, new technologies and new processes such as trapping light and surface passivation, efficient polycrystalline ingot casting, and wet black silicon emerged endlessly. With the comprehensive support of these technologies and processes, the conversion efficiency of polycrystalline cells has broken through the theoretical limit of 20% previously recognized by the industry.

However, the market needs technologies and products with higher conversion efficiency, in order to achieve the goal of PV parity online as soon as possible. The "photovoltaic leader" plan came into being, which aims to promote the photovoltaic industry from the pursuit of scale expansion to focus on quality and efficiency transformation of the top-level plan, forcing photovoltaic technology upgrade.

Driven by the "PV leader" program, various advanced technologies began to compete for innovation and upgrading. In 2014, Longi overcame the industrialization problem of RCZ single crystal growth technology, and the output of silicon rods was increased from the original 60kg/ crucible to 1500kg+/ crucible. The application of this technology has increased the crystal pulling speed by more than 80%, rapidly narrowing the cost gap per kilogram between monocrystalline silicon rods and polycrystalline ingots, and rapidly narrowing the huge cost gap between monocrystalline and polycrystalline, providing an opportunity for the rapid development of single crystals. In 2020 alone, this technology will save about 13.6 billion yuan for China's photovoltaic industry. At the same time, another key technology related to the future of single crystal, that is, diamond wire cutting technology is also realized in Longji, breaking the monopoly of overseas manufacturers on diamond wire technology in one fell fell, through close upstream and downstream joint technical research and technology introduction, soon developed high-quality, low-cost diamond wire, so that the supply price of diamond wire quickly dropped to about 0.3 yuan/meter. Annual cost savings of 30 billion yuan for the industry.

At the same time, PERC battery technology was introduced, and the cost reduction advantage of single crystal technology was more obvious. Ai Xu, Tongwei, Jinko, JA and other battery module companies have turned to single crystal and PERC technology, so that the value of single crystal components is recognized by the market. Through joint research on the mechanism of light decay with partners such as the University of New South Wales in Australia, Longi solved the problem of high initial light decay of single crystal PERC and opened the LIR technology to the industry. Next, the Pandora's box of single crystal PERC technology was opened, and with the continuous efforts of industry enterprises, new technologies and new processes such as double-sided, half-chip, MBB, imbringle, and multi-main gate continued to emerge, so that the single crystal efficiency curve continued to rise, and the cost also fell again and again. By the end of 2017, single polycrystalline components almost achieved the same price, completing the counterattack war on polycrystalline in one fell fell.

Throughout this process, the cost advantage brought by technology iteration is the key to achieving the reverse attack of single crystal technology, and it is also the power source for photovoltaic costs to decrease by nearly 80% in the past 10 years.

Ten years of transformation: from subsidies to parity

In the past decade, the photovoltaic industry in the pursuit of technological progress at the same time, but also gradually get rid of the dependence on policies and subsidies, not only to achieve the historic leap from the subsidy era to the era of parity, will also realize the gradual transformation from auxiliary energy to the main energy.

On May 31, 2018, the National Development and Reform Commission, the Ministry of Finance, and the National Energy Administration jointly issued the Notice on Matters related to photovoltaic power generation in 2018 (known in the industry as the "531 New Deal"), which reduced the scale of photovoltaic power generation in the second half of the year to less than one-third of the original. The intensity and speed of the reduction of policy subsidies far exceeded expectations, which formed an unprecedented impact on the photovoltaic industry at that time.

The benchmark electricity price and the gradually reduced subsidy intensity have effectively supported the large-scale development of the industry. In 2017, the average on-grid electricity price of photovoltaic is still as high as 0.94 yuan/KWH, and the power generation cost is also 0.5-0.65 yuan/KWH, which is not competitive in price compared with other forms of power generation.

China's photovoltaic industry once again withstood the test, photovoltaic enterprises to accelerate the pace of technology research and development and innovation, the industry "cost reduction and efficiency" pace accelerated, a number of key technologies within a year of policy implementation breakthrough. For example, in the component battery link, according to incomplete statistics, China has created at least 20 world efficiency records in 2019, including both PERC products that have become the mainstream of the market, and cutting-edge technologies such as heterojunction and perovskite that have not yet been large-scale industrialization. Longi set a world record for the positive conversion efficiency of 24.06% single-crystal double-sided PERC batteries, breaking the previously recognized limit of 24% in the industry.

The goal of "double carbon" and the construction of a new power system with new energy as the main body have been proposed successively, giving photovoltaic greater historical responsibility. For the photovoltaic industry, technological innovation in photovoltaic power generation will remain a key factor in addressing these challenges. Wang Bohua, honorary chairman of the China Photovoltaic Industry Association, said: "In the new era, the photovoltaic industry needs to constantly cultivate itself, continuous innovation and development, cost reduction and efficiency, and coordinated development of the industry, in order to make photovoltaic really become the main force of the new power system."