What does 'repowering' actually mean?
Could we use half as many wind turbines and still generate five times as much power? Sounds unrealistic? It certainly can be done. The secret to it is repowering, which helps us get more electricity out of the wind we harness. Want to know how this works? Here is the answer.
'Tuning' wind farms
An energy-saving light bulb will light up your sitting room just as well as a traditional light bulb – and it will also use less electricity. So you can still turn the lights on, but without wasting energy. It's a case of achieving the same result, but with less input. And if you put several energy-saving light bulbs in a chandelier, your room will be lit even more brightly than if you'd used a single standard light bulb – at no additional cost. In other words, you get a better result without having to make any additional input. That's what efficiency is all about: 'Same result, less effort' or 'better result, same effort'. So much for the theory.
In practice, there are even ways of combining both principles, which means that it is possible to get more from less. One way to do this is to make use of 'repowering'.
Turning old installations into efficient ones
Repowering means retrofitting and modernising existing power plants and installations. The idea is to replace older parts or equipment with modern ones that are more powerful. In principle, this can be done with any type of power plant or power installation. Wind power, however, is a technology that is particularly well-suited to repowering.
It will often be possible for a large wind farm consisting of many fairly old installations to be replaced with a much smaller wind farm. In most cases, the new wind turbines will be both much more powerful and efficient – to the point that fewer installations using up less space can feed in more electricity into the grid.
Think that all sounds rather abstract? Well, in that case let's take a trip to North Frisia, to the village of Galmsbüll, whose 600 inhabitants found out about the merits of repowering as early as ten years ago. Back in 2005, there were nearly 60 wind turbines in the village of Galmsbüll, generating a grand total of about twelve megawatts of electricity. Then came repowering, which reduced the number of wind turbines by 38 and increased the wind farm's total capacity to more than 60 megawatts. This means that repowering has resulted in half as many installations generating five times as much power.
2015: 18 per cent of all wind farms 're-powered'
All across Germany, there is dormant potential for improving wind farms using re-powering. After all, the total number of on-shore wind turbines in Germany climbed to 25,980 last year. Much of this stock is more than ten years old. Eighteen per cent of the installations that started to operate last year were constructed using existing wind turbines – which means that re-powering was used on these old installations. The Land to make the most use of this was Schleswig-Holstein, where more than 25 per cent of wind turbines have been 're-powered'. The comparative figure for Bavaria is less than one per cent.
Calmer, quieter, more environmentally compatible
In addition to the technical advantages listed above, re-powering is also an important tool for our energy transition. It has the potential to raise acceptance levels for the energy transition among the general public. People tend to be more tolerant towards wind installations that appear 'calm' as opposed to 'racing rotors'. Back in the 1990s, wind turbines would complete up to 60 rotations per minute. This compares to less than 20 for a modern wind turbine. This means that a wind farm will feel much calmer for the onlooker once it has undergone repowering.
Research for power
Over the past few years, research into renewables has allowed us to use wind power ever more effectively and efficiently. Today, an average wind turbine is more than 100 metres high, compared to 30 metres in 1980. This increase has allowed us to harness much more power. Back in 1980, the average wind turbine would generate 35,000 kilowatt hours of electricity per year, which is the equivalent of the power consumed by ten average households today. It may sound incredible, but it's true: a modern wind turbine can generate 600 times as much electricity.