Compared with onshore wind turbine, China's offshore wind turbine has developed relatively late, and has added components and steps such as submarine cables, foundation piles, and offshore projects. It is difficult to construct and costs are generally high. For a long time, it needs to rely on electricity subsidies to maintain the rate of return on investment. In January 2020, the Ministry of Finance, the National Development and Reform Commission and the National Energy Administration jointly issued the Several Opinions on Promoting the Healthy Development of Non-water Renewable Energy Power Generation, proposing that the new offshore wind power will no longer be included in the scope of the central financial subsidies, and that the stock offshore wind power projects that have been approved (filed) as required and completed the grid connection of all units by December 31, 2021 will be included in the scope of the central financial subsidies according to the corresponding price policy. Affected by this, at the end of 2021, there was a rush to install offshore wind power. The new installed capacity of offshore wind power in 2021 was 16.90GW, with a year-on-year increase of 452.29%, a record high; the cumulative installed capacity reached 26.39GW.

The wind turbine bearing is a movement hub, including the drive system bearing and yaw pitch bearing.

The wind turbine bearing is the hub of all moving parts of the wind turbine. As the core component of the wind turbine, the stress and vibration of the wind turbine is complex, and it must be able to withstand a huge impact load, work in corrosion, sand, humidity and low temperature environment, and meet the requirements of 20 years of service life and high reliability. The bearing industry plays an important role in the "12th Five-Year Plan". In the Implementation Plan for the Revitalization of Mechanical Basic Parts Industry issued by the Ministry of Industry and Information Technology of the People's Republic of China in 2010, the wind turbine bearing is listed as the first of the seven key parts that need to be broken through. According to the Brief Description of Bearings for Wind Turbines, the bearings of wind turbines include:

1) Drive system bearings: wind turbine main bearings, gearbox bearings and generator bearings. The main shaft of wind turbine generator is also called low-speed shaft or impeller shaft, which plays the role of connecting impeller and gearbox or generator, and transmitting torque. The main shaft is supported by the main shaft bearing, so the force and deformation on the main shaft affect the main shaft bearing. The force mainly includes the weight of the wind blade and hub, the weight of the main shaft, the bearing force of the main shaft bearing, the thrust force of the thrust bearing, and the force of the wind acting on the main shaft through the wind blade and hub. Therefore, the main shaft bearing mainly bears the radial force, and also the axial force generated by the wind force. The gearbox plays a role in raising the lower speed transmitted by the rotating blades to the rated speed of the generator; In addition, the wind turbine completes the conversion of mechanical energy to electrical energy, and the internal structure also uses bearings.

2) Yaw, pitch system and its bearings: Yaw bearing is an important part of the yaw system. It is located at the bottom of the engine room, bearing all the mass of the main drive system of the wind turbine generator, and transmitting the aerodynamic thrust to the tower for accurate and timely adjustment of the windward angle of the wind turbine. The variable pitch system is used to adjust the windward direction of the blades; the pitch bearing is installed between the blade and the hub, and the inner and outer rings are connected with the blade and hub through bolts, so that the blade can rotate relative to its axis to achieve the purpose of pitch.