Figure 75 Wind turbine technicians carrying out blade inspection, courtesy of Mistras Group.
Function
Blade inspection and repair consists of the inspection of the condition of blades and replacing or repairing blades in a timely and cost effective manner.
Who supplies them
Service suppliers include Bladefence, Cyberhawk, Deutche Windtechnik, DNV-GL, FORCE Technology, GEV, Global Wind Service, James Fisher Marine Services, Mistras, Natural Power (Fred. Olsen), Swire Renewable Energy and 3Sun.
Inspection technology suppliers include ABJ, Anakata Wind Power, BladeBug, Cornis, Scoptico, SkySpecs and TSR Wind.
Key facts
Blade maintenance and service is an area of specific focus in the offshore wind industry. Issues such as leading edge erosion have been the source of availability issues in the industry and proactive blade inspection and preventative repair is now widely pursued in response.
Blade inspections are performed by drones equipped with high-resolution cameras, by rope-access technicians or by high-resolution camera equipment located on the transition piece or vessel.
Where substantial repairs or blade replacement are required, this is sometimes possible using rope access teams often using a blade platform suspended from the hub. Where a blade cannot be repaired in-situ a jack-up vessel is typically required in order to deliver the swap-out, although smaller vessels than those used during turbine installation can be used. Exchange is carried out in one visit, followed by off-site or deck-based repair. Retrofit programmes are carefully planned to ensure effective vessel utilisation taking into account repair turnaround times.
Blade inspection work typically requires the turbines to be stationary, therefore there is a focus on performing inspection work during the less windy periods of the year to minimise lost energy production. Specialist expertise is required to undertake damage diagnostics and repair activities.
Automation of blade inspection and damage diagnostics is an active area of innovation.