Consideration of ‘bat shutdown’ in wind power forecasts

enercast offers an additional functionality regarding forecasts for wind turbines – ‘bat shutdown’. In Germany, regulations apply  to animal and nature conservation and under certain conditions, wind turbine activity must be reduced or turbines deactivated in order not to endanger bats. enercast takes into account ‘bat shutdown’ in wind power forecasts.

 

In Germany, there are about 25 different species of bat, all of which are protected by nature conservation laws. These small beneficial creatures are already threatened with extinction due to the consequences of intensive farming. It is therefore important to protect bats and to save them from damage caused by wind turbines. enercast takes into account ‘bat shutdown’ in its wind power forecasts.

 

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Animal welfare as a reason for the shutdown of wind turbines

 

Wind farm operators are being subject to more and more restrictions, notably regarding shutdown of turbines in the case of of bat activity. This is mainly due to the location of the wind farms, most of which are in the north of Germany, with premium locations having already been developed. Other areas must be avoided and the requirements of animal and nature conservation have to be taken into account. With the construction of further wind farms, shutdown of turbines due to bat activity is becoming more and more important.

 

Conditions for bat shutdown

 

Near Hannover and Bremen, for example, there are two such wind farms where  enercast provides forecasts, which take into account the shutdown of wind turbines due to bat activity. The conditions are quite different. In the first wind farm, there is a so-called ‘bat reduction’ (a planned reduction in output due to bat activity) from the beginning of May to the end of July, from one hour before sunset until four o’ clock in the morning. During this time, five out of seven wind turbines are shut down to protect the nocturnal creatures.  This is on the condition that the wind speed is less than 6.5 meters per second and the temperature at gondola height is more than ten degrees Celsius.

 

In the second example, the ‘bat reduction’ takes place from the beginning of August to the end of September. Since bats are nocturnal creatures, four out of a total of twelve turbines are shut down one hour before and one hour after sunrise, subject to the following conditions: wind speed is less than 7.2 metres per second and temperature is more than ten degrees Celsius.

 

Bat shutdown in wind power forecasts: High forecasting quality for wind farms

 

enercast combines weather forecasts from several models to achieve a highly accurate result. If all factors described above are met, the shutdown of the corresponding turbines to protect the bats is included in the enercast wind power forecast. The shutdown itself is carried out by a turbine control unit and is automatically controlled by sensors. It is essential that the wind power forecasts for the respective turbines are also corrected for the night-time periods. The shutdown of several turbines reduces the output of the entire wind farm – after all, large turbines produce an output of more than four MW!

 

Financial advantages for wind farm operators

 

enercast takes into account this loss of performance due to bat shutdown in the wind farm’s performance forecasts and thus offers a high overall forecasting accuracy. Once again, the direct marketer of the wind power plant benefits from the most accurate possible forecasts, which predict how many MW a turbine will generate: after all, whether a turbine produces 30 MW or 40 MW has a significant financial impact. If a forecast is not accurate, so-called balancing energy costs are applied. These occur because either more or less wind energy is fed into the grid than predicted. This can be prevented by the use of enercast wind power forecasts which also allow for bat shutdown.