4 bad excuses to not inspect wind turbines
I often hear the same “good” reasons to not inspect blades regularly. Are these trully justified?
“I don’t inspect my blades because my wind turbines are operating very well”
How can you be so sure? Most of the blades seemed to be operating well before they broke. Waiting for the blades to break will cost you much more than inspecting them on a regular basis. The replacement of a single blade can cost you \$200,000 (Source). Out of the 700,000 blades in operation globally, 3,800 have been reported failing each year (Source).
“I don’t inspect my blades because they are under warranty”
In the meantime, make sure that your supplier is doing the inspections properly. Most of the blade failures occur during the first two years of operation (Source).
Many owners perform independent blade inspections just before the end of the warranty. Based on these inspections, you can see what issues your blades have. If there were any to begin with and most importantly, it will tell you all the repairs that can be covered by your warranty contract. Remember that once the blades are out of warranty, maintenance costs are your responsibility.
“I don’t inspect my blades because I don’t have the budget for it. I focus on the repairs.”
Reactive maintenance for the average utility-scale wind farm can cost \$1.5 million more each year than preventive maintenance (Source). By doing quality inspections you insure that the repair team, who can cost you \$300 per hour, is effective. Knowing the exact location of your blade’s defects, the root cause and how they evolved over time, is crucial for the repair team to know. To put it another way, higher inspection costs can lead to significant lower repair costs. For example, a \$400 blade inspection of a given turbine allows you to know the precise location of the defects to be repaired. This inspection saves the repair team valuable time - two-thirds of their time to be exact, as they send technicians only to the single blade that needs be repaired and not on the three of them. Never forget, inspections are as important as repairs!
“I don’t inspect my blades because last time we did it was useless, we didn’t find any serious defects.”
No matter what you find when you do a blade inspection, it is useful. All blade inspection results help to predict the lifespan of your blade and when maintenance work will be required. The key is actually to find defects at an early stage to avoid failures and unscheduled maintenance costs. These unschedule costs are usually higher than scheduled maintenance costs because of the uncertain price of crane rentals (Source).
