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Environmentally friendly and cost-effective first in Wageningen for bird protection

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On a 150 kV high-voltage line between Dodewaard and Ede, TenneT conducted a pilot with drones to hang wire markers for birds. A first in the Netherlands. Normally, TenneT works with helicopters or cranes and climbers are used to install wire markings. Using a drone is both more environmentally friendly and cost-efficient, as it does not require heavy machinery on land or helicopters to fly. Under the supervision of contractor Qirion, Slovak drone company FiiHaa carried out the work over a length of two kilometres on the route near Wageningen for TenneT.

This technique requires a different type of wire marking than TenneT already uses. Namely the so-called Firefly, which can be attached with a clamp to the lightning conductors in the high-voltage line. Drones cannot yet apply other types of wire marking such as pig curls or bird flaps. Based on several studies abroad, the effectiveness of Fireflies is at least as effective as that of pig curls and bird flaps and leads to about 90% fewer wire casualties.

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Risks to birds

The high-voltage grid can pose risks to birds coming into contact with it. For example, when birds in flight fail to see the lightning wire and fly into it. The eyes of many bird species are not forward-facing, so visibility in flight is not optimal. TenneT is therefore committed to limiting damage at the population level of birds by applying the most effective measures at the right locations. These locations have been determined by comparing the location of the high-voltage grid with the distribution of bird flight movements. Connections are made more visible to birds by hanging plastic or metal markings on the lightning wire.

Application to other connections

TenneT ecologist Jac Hakkens: "Commissioned by TenneT, Sovon Vogelonderzoek Nederland (SOVON) investigated where in the Netherlands the risk of wire casualties is highest. This connection near Wageningen was on our list as a priority. We are now evaluating this new method with the drones. If the results prove positive, we can start using this type of wire marking on other compounds as well."

Existing and new connections

During the construction of new high-voltage connections, or during major maintenance, wire markers are routinely mounted. On existing connections, however, it is expensive to hang them. This is because safety measures have to be taken and because the high-voltage connection has to be decommissioned. As far as possible, the mounting of pigskulls is therefore combined with the next maintenance or modification. Fixing wire markers can also be very expensive if they cannot be installed from the ground, for example in difficult terrain such as rivers and wet subsoil. In such cases, helicopters are sometimes used to attach the markings. In comparison, applying with helicopters is a factor of 20 more expensive than applying with drones and causes much more disruption to the surrounding area.


Woordvoerder Jorrit de Jong

Jorrit de Jong


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