Leading Edge Erosion

A serious and expensive issue

Leading edge erosion is a serious and very expensive issue in the wind industry, with the majority of wind turbine blades affected, and particularly severely offshore.

Causes and impact

Leading edge erosion is caused by repeated bombardment of the wind turbine blade, primarily by raindrops and particulate matter, such as hail, ice, salt and UV. Ever larger rotor blades have resulted in increasing rotation speeds of the blade tips which can exceed 330 km/h offshore. At these speeds, multiple shock wave impacts  damage the blade surface and most leading edge protection solutions, including the adhesive bond that bonds the protection to the blade. 
Ultimately, rain and particulate bombardment can erode the surface coating and protective layers, and eventually expose the blade laminate. The tip sections and leading edges of the blades are worst affected. The surface roughness that results from this erosion process creates resistance and drag, which impairs the aerodynamic performance of a blade, reducing wind turbine efficiency and therefore decreasing the generating capacity of a windfarm, which consequently reduces annual energy production and therefore return on investment.

Ongoing maintenance

In order to operate blades at acceptable performance levels the leading edge surface must be aerodynamically optimal, therefore any surface roughness caused by leading edge erosion must be repaired and cost effectively protected from further damage. This creates significant operational and maintenance challenges for all wind farm operators but is amplified offshore.

Repairs and costs

Leading edge erosion also risks adversely impacting the structural integrity of operational blades as water ingress and UV light exposure can result in structural damage. If the erosion is not addressed and leading edge protection successfully applied before damage escalates, it will require ever more invasive composite repairs. Ultimately this cycle can result in blade failure, which can significantly impact overall wind farm returns.
Leading edge erosion proves costly for offshore windfarm owner/operators through increased operational expenditure and reduced revenue at a time when zero-subsidy offshore wind farms and highly competitive auction bids mean the need for cost reductions has never been higher.