Why dirty blades cost energy
A blade’s leading edge shapes the airflow over the whole airfoil. Insects, dust, oil and bird droppings roughen it, and roughness costs lift. On older stall-regulated turbines, insect build-up caused production losses of up to 25%, and at high wind speeds power was sometimes halved (Corten & Veldkamp, Nature 2001). Modern pitch-regulated turbines lose less than that. Modelling still puts the annual energy loss from 200 µm of insect roughness at 4.9–6.8% (Wilcox & White 2016).
Towers and nacelles collect oil, grease and soot. A clean surface also makes new leaks and damage easier to spot.
South Africa had 3,807 MW of wind under REIPPPP at 30 June 2025 (CSIR 2025). We found no published data on blade soiling at South African wind farms, so we compare power curves before and after cleaning on your own turbines.
Contamination or erosion?
Cleaning fixes contamination, not erosion. Before we plan a clean, we check which one you have.
| What | Contamination | Leading-edge erosion |
|---|---|---|
| What it is | Insects, dust, oil, soot or droppings stuck to the surface | Blade material worn away: pitting, gouges, exposed laminate |
| Energy cost | Depends on the build-up | 0.9%, 1.6% or 2.6% of annual energy by damage category at a 6 m/s site (IEA Wind Task 46, 2023); modelled at 3–5% for light erosion and up to about 25% for heavy pitting (Sareen et al. 2014) |
| Fix | Cleaning | Repair and leading-edge protection by a blade-repair specialist |
| Does cleaning help? | Yes | No |
After moderate erosion was repaired in the BLEEP project, measured annual energy rose 1.5–2% (ORE Catapult 2016). If our inspection finds erosion, we tell you: you need a repair team, not a clean.
How a drone blade clean works
Select a step to jump to it. The dwell is shortened in the animation; the method needs five minutes.
- Inspect the blades, tower and nacelle, and review the turbine’s data.
- Plan the dilution by contamination: 1:10 for heavy, 1:20 for medium and 1:30 for light, in ordinary water. The turbine is stopped and secured under the wind farm’s own safety procedure.
- Spray the diluted agent as a foam, at least 0.1–0.2 L per m². Its green marker pigment shows the operator exactly where it has landed on a white blade.
- Wait five minutes.
- Rinse with a high-pressure water jet.
- Check the result with photos, and compare power curves before and after.
The product
Chemitek’s Drone Wind Turbine Cleaning Agent, in its maker’s own figures:
| Property | Chemitek’s figure |
|---|---|
| Removes | Dust, grease, oil, soot, carbon deposits, bird droppings and other organic residue |
| Dilution | 1:10 heavy, 1:20 medium, 1:30 light |
| Quantity | At least 0.1–0.2 L of diluted product per m² |
| Dwell and rinse | 5 minutes, then a high-pressure water jet |
| Surfaces | Aluminium, stainless steel, titanium, copper, plastics, rubbers, epoxy resins, and lacquered, coated or painted surfaces |
| Profile | Water-based, non-flammable, solvent-free, readily biodegradable; green marker pigment |
| Application | Developed for drones; also suits other spraying systems |
What you get
- An inspection record of contamination and any erosion, with photos.
- A cleaning plan: dilution, quantity, dwell, rinse and safety steps, fitted to the wind farm’s procedures.
- The clean itself, by drone, or by your own team with the product, our guidance and the safety data sheets.
- A before-and-after comparison of power curves, so you see what the clean recovered.
Drone, rope access or your own team
Because the agent also suits other spraying systems, your own maintenance or rope-access team can apply it, with our dilution guidance and safety data sheets. Wind farm contracts usually require GWO Basic Safety Training for anyone working on a turbine, and rope-access technicians typically hold IRATA certification. Drone work needs the SACAA approvals set out on our drone cleaning page.
If you run the wind farm’s O&M, we can work alongside your team rather than replace it.
