Source: ExxonMobil Industrial Lubricants
Robert Pears, Renewable Energy Business Development Manager – UK & Ireland, ExxonMobil Lubricants and Specialties, provides advice as to how operators can optimise wind turbine performance and reduce unscheduled downtime through lubricant selection and best practice.
Wind turbines today are running faster, longer and more efficiently than ever before, but to help meet the UK target of generating 15% of its energy supply from renewable sources , electricity generated from wind turbines must become more price competitive.
To optimise wind turbine performance, advanced lubrication and related services have been developed to help wind farm operators to increase wind turbine availability and reduce unscheduled downtime.
Minimising unscheduled downtime is a particularly important factor for those wind farms currently under construction over 100 miles offshore. In addition to the high costs associated with replacement parts and labour, the logistics of reaching wind turbines far out at sea can run into six-figure sums, covering such costs as the chartering of specialist ships to carry out the maintenance.
High Performance Synthetic Lubricants
The good news is that by selecting advanced oils and greases, and adopting a proactive approach to maintenance, wind farm operators can significantly improve the productivity of their operations and reduce costs.
For example take the main gearbox, a key component of a wind turbine. To help maximise productivity and reduce unscheduled downtime, the gear oil needs to offer high levels of performance in all the critical areas required to keep a gearbox working efficiently. This includes outstanding oxidative stability and water tolerance, excellent long term filterability and superior gear and bearing protection. It is critical that the gear oil has a carefully balanced formulation to provide all round protection and performance.
Mobilgear SHC XMP 320, with its balanced formulation, exceeds the performance of conventional, mineral-based oils by extending the interval between oil changes from 18 months to three years or more. The fully synthetic gear oil is used in over 30,000 wind turbine gearboxes worldwide. It is approved by the majority of the top twelve global wind turbine manufacturers and it is the initial fill choice of many key wind turbine manufacturers.
As well as the gearbox, wind farm operators should look to incorporate high performance oils and greases as applicable across the entire wind turbine including the main, pitch and yaw bearings. Mobil SHC Grease 460WT is proving a compelling choice of synthetic grease for the lubrication of main, pitch and yaw bearings due to its excellent low and high temperature performance, structural stability even in the presence of water, excellent false brinelling and wear protection, and rust and corrosion inhibition. It allows consolidation of main, pitch and yaw bearing greases into one product, minimising the risk of re-lubrication with the wrong product and without introducing unnecessary operational risks.
Oil and Equipment Condition Monitoring
The selection of high performance lubricants should be supported by routine, scheduled maintenance, including oil analysis. Routine oil analysis is one of the most widely used proactive maintenance strategies for wind turbines, and employs a test slate that is designed to evaluate the condition of the in-service lubricant and equipment. Maintenance professionals can extend the lives of both the equipment and lubricant by detecting and acting on early warning signs such as oil contamination, cleanliness levels or increasing wear metals using routine oil analysis such as ExxonMobil’s Signum service, as part of a preventative maintenance programme.
To obtain the greatest benefit from oil analysis, it is important to work closely with an expert lubricant manufacturer and participate in oil analysis typically every six months. Identifying trends in the data will help maintenance professionals make better informed decisions.
That way, where a trend or sudden change in equipment condition is detected, corrective action can be taken to help reduce unscheduled downtime. Oil life can also be extended by implementing a programme in which the lubricant is changed when its condition warrants, rather than on a time-based maintenance schedule. Typically, wind turbine manufacturers state gearbox oil change frequencies of 18 months for mineral oils and three years for synthetic lubricants. By employing an oil analysis programme in a condition based maintenance regime, synthetic oil lubricant life can be extended beyond five years.
By introducing technologically advanced synthetic lubricants alongside an effective oil equipment condition monitoring programme, wind farm operators can look to reduce costs and maximise the productivity of wind turbines, including those operating in remote, offshore locations.
Top-tips to help maximise wind turbine performance
• Wind farm operators can significantly improve the productivity of their wind farm operations and reduce costs by selecting advanced oils and greases, and adopting a proactive approach to maintenance
• It is critical that lubricants, such as gear oils, have carefully balanced formulations to provide all round protection and performance.
• Fully synthetic gear oils can extend oil changes from 18 months to three years or more
• As well as the gearbox, wind farm operators should look to incorporate high performance oils and greases across the entire wind turbine including the main, pitch and yaw bearings
• To identify the best lubricants for use in a wind turbine, visit the Mobil Industrial Lubricants website
• The selection of high performance lubricants should be supported by routine, scheduled maintenance, including oil analysis
• To obtain the greatest benefit from oil analysis, it is imperative to work closely with an expert lubricant manufacturer and participate in oil analysis typically every six months. Identifying trends in the data will help maintenance professionals make better informed decisions
 Energy Targets by 2020 -European Commission
ExxonMobil advanced lubrication; maximising wind farm productivity
Source: ExxonMobil Industrial Lubricants