With 45GW of onshore wind capacity in Europe set to reach its end of operational life by 2026, repowering could prove vital for the future of the wind industry. While some wind farms will inevitably be decommissioned and others will benefit from lifetime extension, in many cases rebuilding wind farms from the ground up with more powerful turbines will be the best way for operators to make the most of the wind industry’s prime locations.
A handful of standout projects are proving that the replacement of older models with more efficient and technologically advanced turbines has the potential to hugely increase capacity.
The Windplan Groen project in the Dutch province of Flevoland, for example, used to have 98 turbines with a total capacity of 168MW. These are now being replaced by 90 more powerful turbines, which will take the total capacity of the wind farm to around 500MW, enough to power the whole province. Of these turbines, 37 will be Vestas’ 6MW model – not only the company’s most powerful machines but also the most powerful ever installed in the Netherlands. A wind farm at Malpica in Galicia, Spain, has seen an even bigger transformation. The number of turbines went down from 69 to seven, but true electricity output doubled.
“Projects such as Windplan Groen and Malpica show how big an impact repowering can have. Replacing old turbines with more powerful ones is a very effective way to produce more renewable electricity quickly. Older turbines are generally built where the wind blows the most. New technology can produce much more electricity in these places,” said Giles Dickson, CEO of WindEurope – a body that advocates wind energy policies for Europe on behalf of more than 450 member companies – in a March 2022 press release.
“But permitting for repowering is just way too slow and complicated right now,” he added. “Governments need to change their approach and facilitate repowering by drastically simplifying the permitting procedures.”
Repowering projects are underway all over the rest of Europe, with most in 2021 taking place in Germany and Austria. There was also some activity in Belgium, Greece and the UK. However, out of the 14GW of onshore wind installed in 2021, only 515MW came from repowering projects.
WindEurope is working to ensure those numbers increase moving forward, in part by driving effective communication and engagement with political and regulatory decision-makers. At a broader level, the organisation seeks to facilitate national and international policies and initiatives that strengthen the development of European and global wind energy markets, infrastructure and technology.
“We see capacity running that is already 30 years old, which definitely needs to be replaced soon. Most of our installed capacity today will reach the end of its operational life by 2050,” says Ivan Komusanac, electrification advisor at WindEurope. “We don’t want to lose sites that were commissioned 20 or 30 years ago. These sites often have the best wind conditions and they have reliably produced renewable electricity up until now.”
To repower or not to repower?
That said, not every wind operation is suitable for repowering – each farm must be examined on a caseby- case basis. Stakeholders need to ask, essentially, does it make money at the end of the day?
“When a turbine is 20 years old, operational costs are higher and you have to put much more into maintenance and spend more on parts,” Komusanac explains. “You need to look into the prices you can secure for electricity and see how much money you can get on the market versus how much you need to spend on the machine. If that equation works, operators will keep running the farms but if it’s close to zero, you have to think about redoing the whole thing.”
The availability of spare parts is another factor to consider, particularly with the recent consolidation in the market – some parts that were designed for wind turbines built 25 years ago are no longer in production. “If there are spare parts available, you will do a cost estimate and see if your project makes financial sense or not. If you don’t have spare parts, you realise: ‘Okay, I have to do repowering’,” Komusanac says.
Permitting problems
It’s crucial to ask these questions early on, due to the complex permitting procedures around repowering. “You cannot do this overnight; you can’t wait until it stops working and then think about how to proceed,” Komusanac stresses. “You have to start planning at least five years ahead.”
Then, once the decision has been made to repower, operators must continue running their operations to maximise existing assets, at the same time as starting the really hard part – applying for a new permit.
“You have to go to your planning authorities and something might have changed in terms of urban requirements, or you might want to use a larger land area,” says Komusanac. “The problem we have right now is that you have to go through the same steps as if it were a new wind farm.”
It is this part of the process that WindEurope is asking governments to streamline. At present, the organisation says, there are too many spatial planning constraints, too many administrative authorities involved at the national, regional and municipal level. At the same time, permitting authorities lack sufficient digital and human resources to process the growing number of repowering applications.
“We’re basically going all around Europe trying to look at different permitting regimes and taking lessons from them,” Komusanac says. The organisation also has high hopes for the permitting guidelines set to be released by the European Commission in the spring of 2022.
Processes to streamline
Areas that Komusanac says could be streamlined include the process of ascertaining the impact a repowered wind farm will have on the grid. “We have machines that are performing much better, that have better capabilities than the previous ones. There should definitely be a fast check. This would cut one corner,” he notes.
The spatial planning process could also be significantly accelerated. At present, in many cases, operators must wait for 30 days just for a first reply. “This could be much simpler, perhaps in a digital format with tick boxes,” Komusanac suggests.
But the biggest hurdle is without a doubt the environmental impact assessment. For greenfield projects, it takes two years in certain countries just to monitor the different species in the area. But even with repowering projects, there can be issues if endangered animals move to the location of the wind farm since it started operating. “At one wind farm in Germany, [a rare species of bird] migrated and found sanctuary there. But you cannot build a wind farm next to an endangered species, even [if] that species has moved there and lived in harmony with the wind farm for several years,” Komusanac explains.
For many early onshore wind power projects, environmental and nature mapping, and motoring of proposed sites, were in their nascency – meaning that the presence of endangered species could easily have been missed at the time. In many countries, repowering permits cannot be granted if a protected species makes it home in an area that could be negatively affected by wind turbines.
“Perhaps we need to have a preliminary screening rather than the full screening that is being carried out now,” Komusanac suggests. “And obviously assessors need to take into account the fact that species may have migrated, and that in some cases will be helpful.”
Repowering can present further challenges when it comes to environmental impact – for example, taller turbines pose a greater risk of interfering with set migration routes for birds of all kinds. Many countries have strict prohibitions on turbine height in certain areas – such as near rivers, which many migration paths tend to follow.
The good news is that repowering projects tend to have fewer turbines, a quarter less on average than older wind farms. “This will definitely help, not only from an environmental point of view but also from a public acceptance perspective,” Komusanac notes.
Accelerate repowering
Once a project has been permitted, it’s time to think about financing again. Do you go for a subsidies scheme or an auction or do you sign a PPA? Then commissioning starts. “At the same time as you’re preparing to decommission the old project, you have to plan how it will be recommissioned,” Komusanac notes.
“It takes time to disassemble everything, transfer it off the ground and, depending on the national regulations, figure out what to do with the foundation and how deep you have to go to remove it. The concrete that is removed can sometimes be used for the new wind farm, so it’s wise to plan the period of commissioning at the same time as decommissioning, so that in a year or two both processes can be carried out.”
In 2021, 396MW of wind power was decommissioned in Europe – 233MW in Germany, 103MW in Austria, 26MW in Denmark, 23MW in Belgium, 8MW in France, 3MW in the UK and finally just 0.2MW in Switzerland. These numbers are only set to increase in the coming years. And while repowering is becoming a more widespread practice – with 515MW of repowered capacity being commissioned in the same year, as mentioned earlier – Komusanac considers this mere baby steps compared with what needs to be done.
WindEurope’s priority over the coming years is to accelerate this process, he makes clear. “In the next ten years, we expect repowering will increase to around 2GW per year, with Germany and Spain the two dominant markets, followed by France, Italy and Portugal,” Komusanac predicts. With substantial work to be done in order to reach that goal, it’ll be a busy decade – but if Europe is to hit its EU energy targets by 2030, it’s vital that the work gets done.
This article first appeared in World Wind Technology magazine.
