The wind blows, but the wind turbines are partially still. Since wind energy is one of the key sources for the energy transition, the question naturally arises as to why. The reasons for this are diverse - from maintenance and repair to weather events and environmental regulations, there are various conditions and obstacles that can affect operation. In a wind farm with multiple turbines, even just one rotor can be still - even though the wind conditions are the same. However, there are also areas where the wind blows very differently, so some turbines operate while others stand still. Depending on the type of turbine, the start-up speed also varies, meaning that one turbine may already be running while another needs more wind to start turning.
One of the most common reasons for wind turbines to stand still is the weather. The turbines require a specific constant wind speed in order to operate efficiently. This speed is about three meters per second. At lower wind speeds, the force of the wind is not sufficient to set the rotor blades in motion.
During extreme weather events, such as storms or icing, turbines can reach their climatic operating limits and may be shut down for safety reasons. In winter, at below-freezing temperatures and high humidity, ice layers can form on the rotor blades of a wind turbine. To prevent these from detaching during operation and potentially posing a danger to people, vehicles, or buildings in the vicinity, the turbines automatically shut down thanks to built-in sensors in the rotor blades. The wind turbine remains stationary until the ice has melted.
Wind turbines must be regularly maintained and occasionally repaired. During this time, they are also shut down for safety reasons. Maintenance includes checking components such as rotor blades, electrical systems, and safety features. Regular maintenance ensures effective and safe operation of the turbines.
Another reason why wind turbines are sometimes idle is grid overload. This occurs when various sources generate more electricity than the grids can currently absorb. In order to prevent an overload of the power grid and a potential power outage, local grid operators typically shut down wind turbines first. This is because wind turbines can be ramped down and up more easily than conventional power plants. Statistics show an increase in the curtailed amounts of wind energy. In 2022, around 7.2 terawatt hours of wind power were not fed into the grid to ensure grid stability . This corresponds to approximately 1.4 percent of Germany's total electricity consumption .
Environmental or permitting requirements often lead to temporary shutdown of a facility to protect animals or humans. During migration and breeding seasons, wind farms may need to be temporarily shut down to avoid bird collisions. Some facilities are also shut down in the early morning and at night during the summer months to avoid disturbing bat flight. In addition, there are specific limits on how much shadow wind turbines can cast on surrounding residential buildings. Certain noise limits must also be adhered to so that residents are not disturbed by the sounds of rotor blades.
There are thus many possible reasons for a rotor standstill - and yet all are the exception to the rule. And that rule is: if there is enough wind, the system runs. Prokon is proud to ensure an availability of around 97 percent on average for its wind farms.
Green electricity directly from the producer
From our own wind farms across Germany.
Mon & Tue: 8:00 – 12:00 and 13:00 – 16:00
Wed: 8:00 – 12:00 (afternoon only written service)
Thu: 13:00 – 18:00 (morning only written service)
Fri: 8:00 – 12:00
Language (Country)
Prokon eG 2024. All rights reserved.
