Servicing of wind turbines

All wind turbines, regardless of size, must be serviced, repaired, and maintained as long as the wind turbine is erected. The wind turbines need to be serviced in accordance with the service manual and the service intervals indicated therein. For a full overview of all the provisions regarding service, please refer to the executive order and the guidance document.

Service on wind turbines over 40 m2 must be carried out by experts and reported: Wind turbines with a rotor area over 40 m2 must be serviced and maintained by a licensed or certified service company, and service must be reported to the Danish Energy Agency. You will find links to service reporting on the subpage for forms and reporting.

On the subpage for service companies, you can see which companies are licensed or certified to service wind turbines, and the types of wind turbines the companies are allowed to service.

Service on wind turbines of 40 m2 or less must be recorded in a log: There is no requirement for service to be reported to the Danish Energy Agency for wind turbines with a swept area of 40 m2 or less, but the owner must keep a log of service carried out on the wind turbine. Examples of content in the log can be found in the guidance document.

Extended service requirements for older wind turbines: The requirements for carrying out service increase with the age of a wind turbine. Extended service shall be carried out when a wind turbine has surpassed its design lifetime. The design lifetime for wind turbines is often 20 years. The requirements for extended service can be found in the fourth annex to the Executive Order.

When a wind turbine is taken out of service or put into operation again: When a wind turbine with a rotor area of more than 40 m2 is taken out of or goes back into operation, the stopping or restarting of the wind turbine must be carried out by companies that are approved or certified for the task. When a wind turbine, regardless of its size, has been stopped, the wind turbine must be correctly secured and serviced. Service must be done at least once a year, unless a shorter interval is specified in the service manual.

See the guidance document for examples of securing wind turbines that are taken out of operation and examples of safety and function testing when the wind turbine is put into operation again.

If a wind turbine breaks down or major damage occurs: If an accident occurs on a wind turbine, or if major damage occurs to a wind turbine, it must be reported without undue delay to the Danish Energy Agency. Read more on the subpage for damage and breakdown.

Good to know

The guidance document is a good place to start, if you want to know more about technical certification and servicing of wind turbines. However, to understand the exact obligations and requirements that apply, it is necessary to read the executive order itself.

PDF | EN | Guidance document

PDF | EN |  Executive Order

LINK | DA |  Executive Order

The service obligation requires, among others things:

  • that the wind turbine must be serviced and maintained following the service manual,
  • that for wind turbines with a rotor area of 40 m2 or above, service must be carried out by a licensed or certified service company and service must be reported,
  • that repairs must be carried out as necessary,
  • that wind turbines that are out of operation still have to be serviced.