Leading Edge Erosion

Leading Edge Erosion (LEE) on wind turbine blades:

Leading Edge Erosion is one of the most critical degradation mechanisms for modern wind turbine blades, particularly as turbines grow larger and operate at higher tip speeds. 

What causes LEE on wind turbines? 

- Raindrop impact at tip speeds of 80–110 m/s (primary cause) 

- Hail and sleet - Sand and dust (onshore, desert, and agricultural areas) 

- Saltwater spray (offshore and coastal turbines) 

- UV radiation, which over time weakens coatings and degrades the blade material, exposing the underlying fiberglass/polyester

Where on the blade does the damage occur? 

- Primarily on the outermost 20–30% of the blade length - Most severe damage at the leading edge near the blade tip 

- The pressure side is often more affected than the suction side 

- Impact on performance - 1–5% loss in Annual Energy Production (AEP) in early stages (Source: DTU) 

- Up to 10–20% AEP loss in severe cases (Source: DTU) 

- Increased noise levels - Higher aerodynamic loads and fatigue - Earlier need for major repairs or, in the worst case, blade replacement

Typical progression of damage: 

- Micro-cracks in the coating 

- Flaking/loss of paint or coating 

- Erosion of filler/putty 

- Exposed laminate 

- Structural damage (if not addressed in time) 

- Inspection and detection 

- Drone inspections with high-resolution photos 

- Monitoring of power curves (unexpected drop in production)