What does the repowering of wind turbines consist of?

Although wind energy is one of the key elements of the energy transition and renewable energies have positioned themselves at the forefront of energy, the truth is that they are not newcomers on the energy scene. The first wind farm in Spain was inaugurated in 1984, in Garriguella (Girona). That was 40 years ago.

And this decades-long history of wind energy also has important implications in terms of usability and efficiency. The optimal operating time of wind turbines is limited, with an estimated useful life of between 20 and 25 years from their installation.  Therefore, some estimates already warn that within a decade – or a little more than a decade – a significant part of European wind turbines will reach this condition.

What to do when wind turbines reach the end of their useful life? The truth is that solutions to this problem already exist. This is when repowering comes into play.

Repowering: restarting the wind farm

The process of repowering a wind farm aims to upgrade existing wind turbines, usually by installing new, more modern and more efficient equipment. This ensures that existing wind farms continue to operate, taking advantage of the existing infrastructure.

This upgrading of the existing infrastructure involves replacing the old wind turbines with modern turbines, whose power generation capacity is much higher, even up to six times the initial capacity. For this reason, although repowering usually involves a reduction in the number of wind turbines in the wind farm, there is a significant improvement in efficiency.

The importance of these processes is such that the Ministry for Ecological Transition and the Demographic Challenge, through the Institute for Energy Diversification and Saving, has already launched a plan, called Circular Repowering, within which the renewal of wind farms is being tackled.

With a budget of 185.7 million euros, from the Recovery, Transformation and Resilience Plan, it has been distributed into three action programmes:

• Repowering of existing wind farms, with a budget of 147.8 million euros, which will enable 34 wind farms to be repowered, replacing 1,205 old wind turbines with 167 new ones.
• Modernisation and environmental improvement of mini-hydro plants of up to 10 MW, with a total of 129 projects selected.
• Promotion of innovative solutions for the recycling of blades, with the aim of creating the necessary recycling infrastructure for the treatment of all blades and composites that will be generated as a result of the various current and future repowering projects.

Compared to the current landfill management, all operators agree that they would opt for an environmental solution based on recovery and the circular economy, promoting the end of disposal. A fundamental objective of the circular repowering plan mentioned above is to encourage the development of recycling plants based on recycling solutions aimed at maximum recovery of the materials contained in the blades. ENERGYLOOP’s technical proposal has been awarded these grants.

So far, only 3% of wind farms over 20 years old in Spain have been repowered, according to experts from the Spanish Wind Energy Association (AEE). The fact that wind turbines are robust, which allows them to be operated beyond their expected useful life; the lack of specific regulations that, for example, allow greater traceability in the different elements obtained in repowering, or the ban on disposal; the processing times for repowering projects are slowing down the process.

The benefits of repowering

Repowering makes it possible to extend the lifetime of existing wind farms. This is very important, because they are usually located in the best wind resource locations.

This is their main advantage, but not the only one. By upgrading wind turbines, you also achieve greater energy efficiency. More electricity is produced. Likewise, as it is feasible to reduce the number of wind turbines, there is less occupation of space and, in turn, a reduced impact on the landscape.

Iberdrola is currently promoting the repowering of four wind farms in Galicia and Castilla La Mancha, which globally entails replacing 237 wind turbines with 38 new ones. The aim is to increase the electricity generated by 30%. The management of all materials from the dismantling of the two wind farms in Castilla La Mancha has been awarded to ENERGYLOOP.