◎Our reporter Chen Yu

The monopile foundation of the 5-megawatt wind turbine has been erected at sea, and its bottom firmly "grabbed" the seabed at a depth of more than 30 meters underwater. However, the fan blade solution has not yet landed.

Blades are like the heart of wind turbines, and their importance is self-evident.

In June, Liu Xin, director of the Offshore Wind Power Technology Department of China Huaneng Group Clean Energy Technology Research Institute Co., Ltd. (hereinafter referred to as Huaneng Qingneng Institute), was interviewed by a reporter from Science and Technology Daily. He still remembered the difficult choice in 2020: yes Choose a carbon fiber blade imported from abroad with mature technology but high price, or choose the first set of carbon glass blade made in China?

Localized equipment rarely has the opportunity to test at sea

In 2009, my country's wind power industry started an attempt to "cross the river by feeling the stones" - the wind turbine was moved from land to sea, which is precisely the intertidal zone.

The intertidal zone is the area where the coast is exposed when the tide is low. Looking back more than ten years later, the industry even bluntly stated that this is not strictly offshore wind power. The intertidal wind turbine has added some redundancy design than the onshore wind turbine, and the load on the wind turbine is almost the same as that of the onshore wind turbine. However, the intertidal zone experimental wind farm project has opened a new era of domestic offshore wind power development and construction.

Since the 1990s, as a type of wind power development with large scale and high annual utilization hours, foreign offshore wind power technology has become increasingly mature today.

In the development of offshore wind power, my country has a natural advantage - a long coastline and a wide available sea area, and wind energy resources are mainly distributed in the southeast coastal areas with developed economy, strong power grid structure and lack of new energy. Under the "dual carbon" goal, my country's offshore wind power has shown its advantages and its development speed has accelerated.

Li Weidong, Secretary of the Party Committee and Chairman of Huaneng Qingneng Institute, told reporters that by the end of 2020, the cumulative installed capacity of my country's offshore wind power has reached the second place in the world, but there are still many key components of large-capacity offshore wind turbines that are monopolized by foreign manufacturers.

Li Weidong analyzed that this is largely because, compared with onshore, the operating environment of offshore wind turbines is more severe and the cost is higher: a million kilowatt offshore wind power airport costs about 15 billion yuan, and it needs to deal with more extreme conditions during operation. climatic conditions, more complex marine environments. Developers therefore rely on more stable and efficient models.

"The equipment of 10 billion yuan is placed in the sea dozens of kilometers away from the coast, and it is usually invisible. If there is a problem with the equipment, if the luck is not good, the maintenance personnel may not be able to survive due to the weather within a week or two, and the economic loss will be great. "Li Weidong said that because of this, people preferred foreign mature and reliable products before, and were reluctant to use localized equipment. To some extent, localized equipment did not even have the opportunity to test.

Work together to break the "strange circle" that cannot be localized for offshore wind turbines

In order to realize the localization of large offshore wind turbines, in 2020, as one of the largest offshore wind power developers in China, China Huaneng Group Co., Ltd. , scientific research institutes and construction enterprises to form an offshore wind power supplementary technical research team, and in 2021, a closer offshore wind power technology innovation consortium will be formally established.

"This is one of the important starting points for my country's future offshore wind power development, and it is also an important guarantee for national energy security. We hope to think about the future of China's offshore wind power from the perspective of the overall industrial chain." In Li Weidong's view, as the "chain of the industrial chain" China Huaneng hopes to unite the entire industry chain and break the "strange circle" that cannot be localized for offshore wind turbines. The 5 MW large-capacity offshore wind turbine is the first step in promoting the localization of large-scale offshore wind turbines. China Huaneng relies on Huaneng Qingneng Institute, and cooperates with Huaneng Jiangsu Company, China Haizhuang and other units to jointly carry out research and development work.

The road to localization has not been smooth sailing. Liu Xin told reporters that major technical challenges were encountered in the process of localization of blades. When designing the single-pile foundation and tower bearing capacity of wind turbines at the beginning, the weight of imported mature commercial blades was considered. The blades of the tile unit are more than 80 meters long. Although the project team has innovated the existing blade design materials and manufacturing technology, the weight of the new blades is still significantly increased compared with the original plan.

Is the fan after weight gain safe? Can the pile foundation that has been built be able to carry this excess weight? A series of problems worry everyone, and it is more directly related to whether the localization work can be done.

As the department responsible for the localization of offshore wind turbines, Liu Xinhe's team adopted the integrated load calculation method developed by Huaneng Qingneng Research Institute, starting from the problem of blade weight gain, to analyze the blade, nacelle, tower and foundation of the entire offshore wind turbine. A lot of detailed calculations have been done on the operating load to confirm that the wind turbine can still operate safely after the blade has increased in weight.

As a "chain leader", China Huaneng encourages other links in the industry chain to actively adopt new technologies with proprietary intellectual property rights and localized new products, and also "exempts" localized equipment to dispel manufacturers' concerns. In the end, the participating units realized the localization of a series of core key components such as blades, main bearings, and gearbox bearings for large offshore wind turbines, and achieved the established goal of localizing all the key core components of the unit.

"This is a road of independent innovation that is problem-oriented and seizes opportunities." Li Weidong concluded.

Localization boosts high-quality development

The success of the localized 5 MW offshore wind turbine not only takes a solid step in solving key problems in the energy field, but also has great significance for the next step of parity development of offshore wind power. It is worth mentioning that China Haizhuang will soon launch offshore wind turbines with larger unit capacity and longer blades, which will effectively reduce the cost of offshore wind power.

Fan Qixiang, a member of China Huaneng's party group and deputy general manager, told reporters that China Huaneng has always attached great importance to independent innovation. Giving the leading talents in the field of Ceyuan a greater right to choose technical routes, control over funds and set up teams, the development of 5 MW localized large-capacity offshore wind turbines is a vivid manifestation.

The "14th Five-Year Plan for Modern Energy System" issued this year proposed that to improve the level of clean and low-carbon development of energy in the eastern region, it is necessary to actively promote the cluster development of offshore wind power in the southeastern coastal areas. At the same time, many places have also anchored the "blue ocean", and the theme of "high-quality leap development" of offshore wind power has gradually become clear, and localization will be an important starting point for promoting high-quality development.

Comments In recent years, the state has issued many policies around the localization of equipment. However, the first (set) of major technical equipment (referred to as "the first set") developed by the company consuming manpower and material resources is often blocked by the market threshold.

There are many reasons for the domestic "first set" to hit the wall everywhere. One of them is that many customers, although they are well aware of the importance of the "first set" to the country's independent innovation, are worried about using the domestic "first set". The attitude of "don't dare to use" is more common when taking responsibility after the problem.

The success of localized 5 MW offshore wind turbines is a win-win result of technological breakthroughs and market breakthroughs. While providing policy support, the relevant departments can further improve the "first set" insurance compensation mechanism, dispel buyers' concerns about choosing the "first set", and make this win-win situation normalized.