Bat Protection System (BPS)

A bat is a protected species by the European law. It is illegal to injure or kill bats and to disturb their habitats. Turbines can cause a problem because a collision with the rotating blades or barotrauma (air pressure change at turbine blades can kill bats by exploding their lungs) can kill bats.

Topwind has developed the Bat Protection System in close collaboration with ecologists and bat experts. Our goal is to protect the bats while at the same time turbine production losses are minimized. The most governing agencies grant you an exemption if you prove that you are proactively protecting the species from harm.

BPS Monitoring

In case of an exemption, you are obliged to monitor the presence of bats. Furthermore, mitigation should be achieved by downtime algorithms, which are usually provided by the authorities. Monitoring means the registration of the bat activity with an ultrasound microphone which is installed in the nacelle floor or generator (for direct drive), close to the swept area. The registrations of all activities are stored on a local storage and available from remote for further analyses.

BPS Protection

In order to reduce the number of collisions, wind turbines in protected areas have to be shut down on the basis of downtime algorithms. Switching off the turbine(s) can be done in two ways:

  1. Weather and date/time-based protection; the turbine will automatically start and stop the turbine based on pre-programmed times and conditions such as date/time, temperature, light intensity, wind speed, wind direction, etc. The BPS registrations can be used to meet the requirements from authorities and to optimise the algorithm every year and minimise the loss of production.

  2. Real-time protection; The BPS system will switch off the turbine when bats are detected and automatically switch the turbine back on when there is no detection for a given period. This option is in development and can be applied at a later stage if the loss of production can be demonstrably reduced.

Weather data

Apart from the microphone, a weather station will be installed. The weather station measures wind speed, light intensity, rain, temperature, humidity and air pressure. All data will be saved and stored in the BPS and is accessible from remote for further processing. In a later stage, the weather data can be used in combination with the bat registrations to argument an adjustment of the algorithm. By adjusting the algorithm the production loss can be further minimized while at the same time optimum protection of the bats is offered.


All data (such as presence, activities and type of bats, shutdowns and weather conditions) is recorded and available through a remote connection. Thanks to the BPS you always have the necessary reports.


  • In close collaboration with the turbine manufacturer the microphone will be installed in the nacelle floor, between the rotor and the tower. This cost-effective solution makes it possible to use one single bat detector instead of multiple detectors on the tower.
  • The BPS power supply will be connected to the turbine power facilities making an independent battery supply obsolete. Batteries may become empty which result in higher service expenses and data gaps.
  • Remote calibration of the bat detector and data collection, which makes frequent turbine visits unnecessary.
  • Combination of ultrasound registrations and weather data gives an accurate view about the bat activity around the turbine.
  • Topwind is known in the wind industry for unique and flexible solutions for any kind of problems. If necessary, the Topwind BPS can be adapted for project specific requirements, e.g. additional bat detectors on the tower or for the use of thermal camera’s.