Ice Throw Report for Wind Turbines
The ice throw report (Eisfallgutachten) assesses whether ice accretion on rotor blades during winter could endanger persons or traffic routes in the vicinity of the turbine. It is required whenever sensitive objects (residential buildings, roads, hiking/cycling paths) lie within the throw range.
What does it contain?
- Site risk analysis: icing frequency based on climate data (DWD), elevation, terrain class
- Throw range calculation per BWE rule-of-thumb formulas (Seifert): standstill 1.5 × (D + H), rotation additionally + Vtip
- Cartographic representation of the throw range with all sensitive objects in the vicinity
- Hazard assessment for traffic routes, residential buildings, and areas where people may be present
- Mitigation concept: ice detection with automatic shutdown, warning signs, path closures
Ice throw range of a WTG — safety distance per Seifert formula (guideline values)
When is the report required?
- Always when traffic routes lie within the throw range (motorway, federal road, railway line)
- Always when residential buildings lie within the standstill throw range
- In most federal states when hiking/cycling paths or main agricultural roads are affected
- At icing-exposed sites (elevation above 600 m a.s.l., mountain ridge locations)
Ice detection — the standard solution
If the rule-of-thumb throw range extends over sensitive objects, a certified ice detection system with automatic shutdown is prescribed. This reduces the decisive safety distance to the standstill value (1.5 × (D + H)).
| Provider | Method | Advantages |
|---|---|---|
| Bofin | Rotor blade vibration analysis | No sensor on the blade required |
| Eologix | Sensor directly on the blade | Direct ice measurement |
| Woelfel iSpin | Combined weather + blade dynamics | Early detection |
What does the report cost?
Guideline value EUR 3,000 – 10,000. For complex path networks and many sensitive objects up to EUR 15,000. Retrofitting an ice detection system costs an additional approx. EUR 8,000–15,000 per turbine (procurement + installation).
Who prepares the report?
Specialised engineering firms for WTG reports (often the same ones that also handle noise and shadow flicker). Certification bodies for ice detection: TUeV Sued, DEWI-OCC, DNV.
Request an ice throw report
We connect you with an engineering firm specialised in icing-exposed sites — including assessment of ice detection as a mitigation measure.
Request a quoteFrequently asked questions
How often do ice fall incidents occur in Germany?
Statistically very rarely — fewer than a dozen documented incidents with personal injury or property damage in the last 15 years. The rule-of-thumb formulas are intentionally designed to be conservative.
Can I retrofit ice detection?
Yes — all major manufacturers offer retrofit modules. Cost approx. EUR 8,000–15,000 per turbine. This often allows a planned standstill condition (e.g. December–February) to be replaced — the yield savings can pay back the investment in 1–2 years.
Do I need the report for repowering?
Yes — repowering also requires a new assessment because the new turbines are usually larger and therefore have different throw ranges. For 1:1 repowering (same turbine types, same locations), a simplified process is sometimes possible.
Can the online calculator do this?
The calculator provides the rule-of-thumb throw range for a single turbine. An official report must additionally assess site climate, topography, and the specific locations of all sensitive objects — which the online calculator cannot do.