The established ways of inspecting onshore wind turbines are by crane or by using drones. Both options are time consuming and expensive.
Sub-contractors are used for the inspections which normally take place every second year.
Telescope in the car
Operations & Maintenance manager at Nuon Teus van Verseveld is an active birdwatcher who usually keeps his telescope in the back of the car.
"I found out that I could use an adapter and attach a camera to the telescope enabling me to take pictures of the rotor blades. I started doing my inspections this summer and it works perfectly. It is faster, I can inspect six to seven turbines a day while the conventional way of doing it can manage maybe two turbines a day."
Since the summer, van Verseveld has inspected 60 onshore turbines in the Netherlands. His findings include a rotor blade damaged by lightning at the Jaap Rodenburg wind farm and a blade showing a substantial crack at wind farm Eemmeerdijk.
"I still keep the telescope in my car and try to carry out inspections as often as possible. This method saves the company money, time and it is safer since no one has to climb the turbine or be hoisted on to it by crane."
Stability is an important factor for van Verseveld's inspections. He uses a tripod for the Swarovski telescope.
"Onshore there is no problem with this method but offshore would be more of a challenge."
Teus van Verseveld recently shared his experiences from inspecting rotor blades with a telescope, with colleagues from the Continental/UK organisation.
"This method enables us to do more frequent inspections and to identify damage at an early stage. Mechanics are then immediately notified. The shorter period of time a turbine has to be taken out of operation, the more money it saves the company."