Decommissioning of Wind Turbines
When repowering, the old turbine must be dismantled and the site restored to its original condition — this is a legal obligation under German law. Here is everything you need to know about the process, costs, recycling status, and the decommissioning surety bond.
What Does the Law Require?
Section 35 para. 5 BauGB (Federal Building Code): the operator must fully decommission the turbine and restore the site at the end of use. This obligation is an integral part of the permit and is secured by a surety bond.
Scope of Decommissioning
- Turbine dismantling: rotor, nacelle, tower sections removed via large crane
- Foundation removal: typically to 1.5 m below surface level (some federal states require full removal)
- Crane pad removal: gravel removed, soil loosened, reseeded
- Access road removal: only if newly built for the turbine; existing roads remain
- Transformer station + cables: removed or taken over by the repowering turbine
- Site restoration: soil and vegetation restored, often returned to agricultural use
Decommissioning Costs
| Item | Cost per turbine |
|---|---|
| Dismantling (large crane + logistics) | 40,000–80,000 EUR |
| Recycling / disposal | 30,000–80,000 EUR (rotor blades main cost driver) |
| Foundation removal (partial) | 20,000–40,000 EUR |
| Foundation full removal (rarely required) | 60,000–120,000 EUR additional |
| Crane pad + site restoration | 10,000–30,000 EUR |
| Transformer station + cables | 10,000–30,000 EUR (if not reusable) |
| Total per turbine | 110,000–250,000 EUR |
| Recycling revenue (steel, copper) | −20,000 to −60,000 EUR (offset) |
| Net cost | 50,000–200,000 EUR |
Decommissioning Surety Bond
Before commissioning, the operator must deposit a financial security — typically:
- Bank guarantee or cash deposit with a bank/insurance company
- Amount: 6.5–8% of the turbine's investment cost, or a flat 100,000–200,000 EUR per turbine
- Interest: retained by the operator, so inflation increases the decommissioning fund value
- In case of early decommissioning: the bond is partially or fully released
Recycling Rates of Modern Turbines
| Component | Share of total weight | Recycling rate |
|---|---|---|
| Steel (tower, main components) | approx. 65% | > 95% |
| Concrete (foundation) | approx. 20% | > 90% as aggregate |
| Copper, aluminum (generator, cables) | approx. 4% | > 95% |
| Ferrous metals (nacelle) | approx. 5% | > 95% |
| Polymers, lubricants, electronics | approx. 2% | thermal recovery |
| GRP rotor blades (glass-fibre reinforced plastic) | approx. 4% | the bottleneck |
Rotor Blades — The Unsolved Problem
Rotor blades made of glass-fibre or carbon-fibre reinforced plastic are currently the biggest technical bottleneck in wind turbine recycling. The available options:
- Cement kiln co-processing: incineration as fuel substitute + GRP ash as cement addite (standard solution in 2026)
- Mechanical shredding: processed into granulate for use in concrete or composites — smaller market
- Pyrolysis: thermal decomposition, fibres partially recoverable — developing, high costs
- Solvolysis: chemical separation, fibre and matrix recovery — pilot plants
Rotor blade processing costs: currently 1,000–2,000 EUR per tonne (vs. 200–400 EUR for steel recycling).
Decommissioning costs and recycling rates — rotor blades as the biggest challenge
Site Reuse Options
- Repowering: the site is reused for the new turbine — construction works can be combined with decommissioning
- Full decommissioning without repowering: usually returned to agricultural use
- PV follow-up use: increasingly attractive, as the site is already anthropogenically pre-impacted — hybrid wind+PV solutions emerging
Decommissioning for your existing wind farm?
We connect you with specialised decommissioning firms (dismantling + recycling) — often bundled with the repowering turbine supplier.
Get in touchFrequently Asked Questions
Who pays the decommissioning costs?
The turbine operator. When repowering, these costs are typically included in the investment calculation for the new turbine.
What happens to the surety bond during repowering?
It is offset: the old turbine's bond is released upon successful decommissioning, while the new bond for the replacement turbine is deposited simultaneously.
Why is full foundation removal controversial?
Full removal (50–120 tonnes of concrete down to groundwater level) has high environmental costs (CO2 emissions, truck traffic, soil disruption). Partial removal to 1.5 m below surface is the standard and avoids most impacts — vegetation grows over it.
What is the current lead time for decommissioning firms?
Specialised decommissioning firms are heavily booked — 6–12 months lead time is typical. Early commissioning as part of the repowering project plan is essential.