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The routine maintenance of wind turbines ensures that these expensive pieces of machinery are efficiently generating electricity. One of the most important components of wind turbine maintenance is the lubrication system.
Main Components of Wind Turbines
Each component that makes up any type of wind turbine is involved in power generation. When analyzing the structure of a typical propeller-type wind turbine, the propeller and its attached blades spin in response to wind exposure to provide energy to the turbine generator. Directly attached to the propeller is the rotor, followed by the nacelle which contains the gearbox, generator, controller, and break. The nacelle sits atop of the wind turbine tower, which encompasses a yaw motor and yaw drive, which plays a role in maintaining the direction of the nacelle towards the wind.
The Role of Lubrication
The specific part of a wind turbine that will be exposed to the strongest of winds is the gearbox, which can be located at a height of up to 300 feet. Since the wind turbine’s gearbox will be exposed to particularly harsh environmental conditions, such as extreme temperatures and potential corrosion from saltwater exposure, lubrication is used to increase the viscosity of this component to withstand any effects that cold weather conditions could have to the gearbox. Furthermore, lubricants, which have a greater heat capacity as compared to hydrocarbon oils, allows the gearbox to transfer and release a greater amount of heat as needed. Recurrent lubrication of a wind turbine’s gearbox is critical to extending the life of this piece of equipment.
While lubrication of the wind turbine’s gearbox is important, many other components of the wind turbine must also be lubricated to ensure their optimal performance. These components include the generator, blades, main shaft, yaw drive, and pitch drives. Many wind turbine components that require consistent and clean lubrication are supported by an automatic greasing system and oil filter. Such greasing systems ensure high oil cleanliness, which can be critical when wind turbines are located in remote locations, such as the desert, in which the entrance of airborne dust and other types of abrasive particles can result in the ultimate failure of the entire system.
Commercially Available Wind Turbine Lubricants
With each of these different wind turbine components requiring continual lubrication, it is not uncommon for a single turbine to require multiple different lubrication products to be used simultaneously. Many industrial companies including ExxonMobil, Shell, Total Lubricants, Castrol, Kluber Lubrication, DOW Corning, Indian Oil Corporation and Amsoil offer specialized lubricants for the international wind turbine market. As the global adoption of wind turbines continues to rise in response to advancements in wind technology, economists estimate that the wind turbine lubrication market will reach a total value of $226.1 million by 2026.
Types of Lubricants
It is estimated that more than 80% of the lubricants used within the wind turbine industry are synthetic. The synthetic lubricants, which are typically polyalphaolefin-based, that are used for wind turbine maintenance can be further subdivided into hydraulic fluid, grease and gear oil, which is considered to be the most important synthetic lubricant for wind turbines.
Since the use of wind turbines for electricity generation is centered around increasing the global utilization of environmentally-friendly energy sources, it is critical that the products used to maintain wind turbines also support this honorable initiative. If there is a leak in the hydraulic system of a wind turbine, released lubricant fluid can contaminate the ground and even reach nearby water supplies. Researchers have therefore investigated the application of biodegradable hydraulic oils to address this concern. Hydraulic oils, which originate from natural mineral oils, demonstrate the potential to be a safe alternative to synthetic lubricants that could otherwise contaminate land or water sources.
Lubrication plays a crucial role in the overall maintenance of a wind turbine system. As the growth of the wind power industry continues to rise, the development of a greater number of high-performance and customized lubricants will inevitably follow.
Sources and Further Reading