Page 8 - Energize January 2022

COVER STORY

costs, construction contracts, the location
of the project, infrastructure requirements
as well as numerous other factors outside
the scope of this document. For this
analysis the assumption has been made
that a utility-scale wind turbine costs
about R17-million per MW of capacity.
With replacement of the main
gearbox being approximately 10% of the
overall wind turbine cost, replacing a
3MW wind turbine gearbox could easily
exceed R5.1 million with transportation,
crane rental etc. Over the 20-year
Figure 4: Typical wind turbine gearbox expected life span of the wind turbine the
main gearbox is expected to be replaced
at least twice due to failure.
If the gearbox life could be extended
by even one year, the replacement costs
associated with the wind turbine life cycle
will be reduced by R510 000 per turbine.
Applying this savings to wind farm
with 50, 3 MW turbines equates to a
savings of more than R25-million over
the life cycle of the wind farm. The saving
does not take into consideration the
down time costs associated with loss of
electricity production which would be
Figure 5: Downtime caused by failure in wind turbine sub-systems validation for a proactive maintenance
programme of this nature.
likelihood of failure through much of the wind turbine’s life cycle. Oil analysis provides a solid
Therefore, reliability is essential to the success of wind energy systems, and this requires foundation on which to build an effective
appropriate condition monitoring of sub-systems like the gearbox. Its is for this reason condition monitoring programme in many
that condition monitoring techniques like oil analysis are considered far more effective applications. In the case of wind turbine
predictive/proactive tools for achieving optimum gearbox performance as, in the case of oil gearboxes, oil analysis has the potential
analysis, the technique can be used to detect the onset of early damage as well as tracking to reduce unscheduled maintenance,
the severity of the damage. improve reliability and extend service
Routine oil analysis is one of the most widely used predictive / proactive maintenance life. The oil analysis tests performed
strategies for wind turbines and utilises a test slate that evaluates the condition of the in- by WearCheck can help wind farm
service lubricant and helps evaluate the condition of internal mechanical components. In operators get maximum value from their
short, routine oil analysis is used as a frontline defence against premature gearbox failures. oil sampling program. When these tests
The three main objectives of oil analysis are to monitor the health of the gearbox, are performed on a routine basis and
monitor the health of the oil and monitor contaminants. Active monitoring of the above the results analysed by our experienced
provides early warning of abnormal operating conditions that can lead to catastrophic technicians, oil analysis can facilitate the
failures if not corrected. maintenance of wind turbine gearboxes
These three objectives can be expanded to six main functions of an oil analysis programme and ultimately, support this promising
which are to: detect abnormal wear, detect oil degradation, detect contamination, optimise form of power generation on the African
service intervals, avoid loss of production and ultimately, to save money. continent and beyond. Let WearCheck
The test slate offered by WearCheck as part of their wind turbine oil analysis programme help you maintain the assets that protect
is designed to achieve these six main functions. our planet.
To illustrate the potential savings that could be relalised with a proactive maintenance
strategy like oil analysis, the below cost benefit analysis was performed. Contact WearCheck, Phone 031 700-5460,
The cost involved in installing a commercial-scale wind turbine can vary significantly support@wearcheck.co.za,
depending on the manufacturer of the turbine, the number of turbines, finance and legal www.wearcheck.co.za

energize | January 2022 | 6