"Copenhageners have something to be proud of. Middelgrunden Offshore Wind Farm is a unique example and showcase of the fact that we have done something for the environment while the public support was present."

These where the words of former Enviromental Mayor of Copenhagen Bo Asmus Kjeldgaard on Wednesday the 6th of May 2001 when Middelgrunden was inaugurated. Now 20 years later are the world-renowned turbines slowly reaching their retirement age. This normally means dismantling and scrapping of the parts. But winds of change may blow in the wind industry. Talk of the town is that recycling and restauration is the new green when it comes to breathing new life into aging wind turbines all over the world.

That is also the case with Middelgrunden. The local Danish utility company HOFOR newly released a press release stating that they are the initiator of a project, that might prolong the life of Middelgrunden’s 20 Bonus turbines. The hope is that a recycling plan potentially will double the life of the farm and reduce CO2 emission.

The CO2 that is emitted in connection to wind turbines are all related to the manufacturing and later scrapping. By reusing and restoring, we can bring CO2 emissions from offshore wind even further down.”

Jan Kauffmann, Director of Finance and Business at HOFOR

“Denmark is increasingly investing in offshore wind farms. But we know that they have a limited lifespan of about 25-30 years. If we can develop a good model for how offshore wind turbines can have their lifespan extended, perhaps even doubled, it will really be a good contribution to the green transition. The CO2 that is emitted in connection to wind turbines are all related to the manufacturing and later scrapping. By reusing and restoring, we can bring CO2 emissions from offshore wind even further down,” says Jan Kauffmann, Director of Finance and Business at HOFOR in a press release.

A pilot project for recycling

The project is the first of its kind in Denmark and the Danish Energy Agency has therefore chosen to provide financial support for the project. The expectation is that the experiences gained from the project can be used for similar projects in the future.

Initially, the project will be carried out as a pilot project on one of the park's northern turbines. It is the engineering company R&D, which in collaboration with HOFOR will carry out the pilot project and map out how to restore and replace the worn components with restored components from other old turbines.

“We are now starting to investigate how worn the turbines are and to what extent we can reuse the existing parts, possibly with repair of damages. Then the plan is to find a suitable nacelle as a replacement for the old one. Here, too, the idea is to recycle – instead of putting up something completely new. There is a market for used nacelles in Germany, for example, and we will try to find a usable nacelle that we can restore and repair so that it is as good as new,” explains Peter Søgaard Winther, Area Manager at the engineering company R&D.

"In my mind, there is no doubt that both partial and full repowering is the future.”

TORBEN JØRGENSEN EXTERNAL CONSULTANT AT FRITZ SCHUR ENERGY

The future is in repowering

At Fritz Schur Energy, we are also eager to see how the project will evolve. Our Technical Sales Director Torben Jørgensen who was one of the key contributors in the development of the hydraulic system, that to this day pitches the turbines at Middelgrunden states:

“It is exciting to see what will happen to the turbines out on Middelgrunden. If it is possible to replace components and restore  vital parts such as the foundations and towers, then we have come a long way in making wind turbine operations an even more sustainable energy source. In my mind, there is no doubt that both partial and full repowering is the future.”

Read the first and second part of story about Middelgrunden here and here

Facts about repowering

  • A wind turbine usually has a lifespan between 20 and 25 years.
  • Repowering can in theory double the life of existing turbines.
  • There are two types of repowering: partial and full repowering
  • In the case of full repowering, old turbines are replaced with new, larger, and more efficient ones.
  • In the case of a partial repowering plan the goal is to renovate and replacing vital parts and thereby prolong the turbines lifespan considerably.
  • Example of a major repowering project: King Mountain in Texas, where 2010 Bonus 1.3 MW turbines have been repowered with new Fritz Schur Energy hydraulics among other things.