Save money on electricity – this is also possible with your own mini wind turbines. However, experts advise against the wind turbine in the terraced house garden. The location is crucial.
Christiane Pflug bought a mill in Vogelsberg. There used to be hydroelectric power here. Today there are batteries in the mill cellar. They store electricity, among other things, from a wind turbine. Every watt counts for them. The bike is behind the house, on a small hill. “For a year,” she says and then proudly adds: “self-made”.
The windmill made of wood rises eight meters into the air. It turns easily in the wind. She built her bike together with the designer Jonathan Schreiber. The Austrian travels through Germany and offers workshops. But he wouldn’t recommend it to everyone. “Above all, it needs a windy location that has no obstacles from the main direction. And no trees directly in front, please,” he says. Expectations are often too euphoric. The designer sometimes has to refuse construction.
expectations are often disappointed
The offer on the market for small wind turbines ranges from small propellers for less than 200 euros to highly professional ones that you put on a foundation in the garden and that can cost 40,000 euros and more. The North Rhine-Westphalia consumer advice center has dealt intensively with such small wind turbines. Their conclusion: most prospective buyers are currently advised not to make a purchase.
The responsible energy consultant Stefan Hoffmann refers to the “wrong expectations” that consumers have. “The promised maximum performance is usually not achieved, especially not inland,” he says. His calculation: with a propeller diameter of one meter and a rotor area of 0.8 square meters, the end result is an electricity value of around 33 euros per year. “A calculation that does not add up with high investments.”
Vibration and noise problems
Christiane Pflug from Vogelsberg will achieve an annual yield of around 1000 kilowatt hours at her windy location. Your advantage: She has no immediate neighbors and lives in the middle of the country. Those who live in built-up areas are in a different situation. “A few hundred watts, more is not possible,” says Stefan Hoffmann from the North Rhine-Westphalia consumer center about the performance that can then be expected.
He and designer Jonathan Schreiber advise against a location in the garden of a terraced house or on the roof of your own home. Because vibrations and noise bring sleepless nights – not only to the homeowner, but also to the neighbors. The Federal Association of Small Wind Turbines also refers to turbulence near the house, which reduces yields.
Plants must be registered
Even small systems must be registered with the electricity network operator and the Federal Network Agency. And each state has different regulations. The state building regulations are decisive.
Basically, more and more federal states, such as Hesse, allow a mast height of up to ten meters without permission. However, Martin Maslaton, a specialist lawyer for energy law, points out: “Sound, shadows and statics must be complied with, even if there are no approval procedures.”
Wind power can fill power gaps
Even if the smallest wind turbines do not deliver the perfect wind yield, they can become a “gap filler” in the ideal location. When the photovoltaic system is not running – at night or during the winter months – the wind turbine fills the power gap. “For me, it’s the icing on the cake when it comes to energy supply,” says Christiane Pflug. “When the battery runs low, the wind has a calming effect on me.”
Whatever may already be turning in some places – small wind turbines are by no means a sure-fire success. And if they bring energy, then they are most effective on a free-standing mast, preferably on a hill with good wind.