Lifetime Extension 20+

Extension of the Operating Licence

- use Resources sustainably!

Analyse unused Potential of the WTG

After 20 years, the operating licence for a wind turbine generator in Germany expires.

Experience shows that the damage to a wind turbine generator over the years of use very often does not correspond to the assumptions made 20 years ago when applying for the operating licence.

In 90% of cases, a 20-year-old WTG is still usable, despite depreciation.

The lifetime extension of a depreciated turbine beyond the planned 20 years can therefore be regarded as a profitable first option.

Only when the WTG can no longer be operated for safety reasons could repowering become more attractive to maintain the location.

Wind and Turbulence Assessments - Planning Ahead

5 Steps to the Expertise Report

  1. First Contact
  2. Evaluation of the Turbine Documentation
  3. Testing of the Components relevant to Stability
  4. Turbine Inspection
  5. Establish Expertise Report

If you would be interested in a non-binding offer for your WTG(s), please send us a short e-mail to

After consultation with you, we check the location of your turbine and the environmental conditions. The offer we make afterwards includes the costs for the wind and turbulence assessment, for the analytical proof of stability and the inspection of the turbine for a condition analysis. We also offer an optional rotor blade assessment.

If an expertise opinion for lifetime extension 20+ is commissioned, this is followed by the evaluation of the turbine documentation, the inspection of the components relevant to stability, the inspection of the turbine and, finally, the preparation of the expert opinion. As a rule, at least 3 months should be planned for these steps.

Analytical Verification of Stability

We inspect according to BWE Principles and the DIBt Guideline.

In order for a turbine not to lose its operating licence, its stability must be proven. 

An expertise report is the basis for licensing authorities regarding lifetime extensions in order to approve the continued operation of the WTG.

We are a member of BWE and authorised by BWE.

We examine your wind turbine generator in accordance with the test methods laid down in the BWE principles "Principles for carrying out an assessment and examination on the continued operation of onshore wind turbine generators (BPW)", as well as the current DIBt guideline for wind turbine generators and the specifications and standards of DNV GL.

As a result, you will receive an expertise report for the continued operation of your wind turbine generator in accordance with the current state of technology.

We are an authorised member of the BWE (german wind energy association) and, as an authorised member of the BWE Expert Advisory Board, we have been appointed as an expert authorised to carry out periodic inspections on wind turbine generators.

Turbine Inspection for Condition Analysis

On-site inspection - from the Tower to the Transformer

A turbine inspection is indispensable for the quality examination of a wind turbine.

The components of the wind turbine generator are inspected electrically and mechanically according to special expert criteria. During the inspection, special focus is placed on the findings from the previous analyses.

The turbine inspection concludes with an overall assessment of the turbine's state.

Rotor Blade Assessment - Optional

We offer a rotor blade assessment in cooperation with the company Special Blade Service - optional.

The aim of the rotor blade assessment is to ensure that the rotor blades are in good condition, to extend their service life and, if necessary, to optimise their performance.

With the help of abseiling teams, an internal and external inspection can be carried out on request, as well as a resistance measurement and also an earth resistance measurement.

In addition, an inspection with a cable platform is possible. The rope platform allows repair work to be carried out directly, which can be useful in the case of lightning damage, for example.

windwise Expertise Reports - from a Team with more than 20 Years in "Wind" Experience

Free personal Consultation - make an Appointment


Augustastraße 47/49a

48153 Münster


Phone: +49.251.590 667 0