XANT’s integrated bat mortality mitigation system


And how to reconcile avifauna and mid-size wind


XANT offers state-of-the-art mid-sized wind turbine technology in the 50 to 500 kW range. XANT wind turbines are specially designed for small industries, farms, schools, villages, resorts or even remote locations without grid support.

DEME has requested a permit to install a XANT M wind turbine on the site of DEME’s headquarters, on the Scheldedijk in Zwijndrecht. In combination with the existing solar panels, the turbine will ensure a clean energy supply to its new buildings with a floor area of 5,600 m² housing meeting rooms, a fitness centre and restaurant and space for around 250 new staff. The XANT M turbine will be located in an area known for the presence of foraging curlews and on the banks of a river which migratory birds follow on their route.

There are two main ways in which windturbines can affect birds and bats: by collision with the turbines themselves, and through disturbance from a zone around them. Observations at various turbines have shown that “local” birds quickly learn to identify the obstacle and fly around it. It is conceivable, though, that birds without local experience, i. e. migratory birds, can come to harm through wind turbines. Because of their smaller rotor diameter and the lower height of the turbines, mid-size wind turbines might cause less deaths among birds and bats than their larger counterparts.

Bat detection systems exist: large wind farms in areas with a bat population are equipped with a centralized system that detects bat activity and selectively shuts down turbines to avoid a collision with the turbine blades. Such systems are highly sophisticated and have proven to be very effective but their cost is prohibitive in case of a mid-size wind project.

XANT and DEME have thoroughly investigated the issue of avifauna mortality at the DEME site in collaboration with Natuurpunt and the Research Institute for Nature and Forest (INBO). XANT has devised a simple but effective bat mortality mitigation system based on measuring additional ambient parameters and automated shut downs when bat mortality is highest. The impact on the Annual Energy Yield is negligible, yet the probability on collision is highly reduced.

During a 3-year monitoring campaign the impact of the turbine on the local avifauna will be investigated and bird mortality will be monitored. A combination of an automated system based on off-the-shelf thermal imaging cameras together with on-site visits has been devised with the expert advice of Grontmij.