In a groundbreaking initiative, Dutch transmission system operator TenneT has successfully conducted a pilot project using drones to install wire markers for birds along a 150 kV high-voltage route between Dodewaard and Ede in the Netherlands. This marks a pioneering achievement in the country, as TenneT typically relies on helicopters, cranes, or climbers to apply wire markers. The use of drones proves to be both environmentally friendly and cost-effective, eliminating the need for heavy machinery on land or helicopter flights.
Under the guidance of contractor Qirion, the Slovakian drone company FiiHaa executed the two-kilometer-long operation on the route near Wageningen on behalf of TenneT. This innovative approach demands a different type of wire marker than TenneT traditionally uses, known as the Firefly. The Firefly can be securely attached to lightning conductors in the high-voltage connection using a clamp. Drones, at present, cannot apply other types of wire markers such as pigtail curls or bird flaps. Research conducted abroad indicates that Fireflies are at least as effective as pigtail curls and bird flaps, resulting in approximately 90% fewer bird casualties.
The high-voltage network poses risks to birds that come into contact with it, especially when birds in flight fail to see the lightning wire and collide with it. Many bird species have eyes that are not forward-facing, affecting their visibility in the direction of flight. In response, TenneT is committed to minimizing bird population damage by implementing the most effective measures at strategic locations. These locations are determined by aligning the high-voltage network's layout with the distribution of bird flight patterns. Visibility for birds is enhanced by attaching plastic or metal markers to the lightning wire.
TenneT ecologist Jac Hakkens stated, "Sovon Vogelonderzoek Nederland (SOVON), commissioned by TenneT, researched areas in the Netherlands with the highest risk of wire-related bird fatalities. The Wageningen connection was a priority on our list. We are currently evaluating this new drone method, and if the results are positive, we can extend the use of this wire marking type to other connections."
During the construction of new high-voltage connections or major maintenance activities, wire markers are routinely installed. However, for existing connections, it is costly to implement this measure due to safety precautions and the need to temporarily shut down the high-voltage line. Attaching pigtail curls is often combined with the next maintenance cycle or modification due to these constraints. Additionally, installing wire markers can be expensive if done from the air, particularly in challenging terrains such as rivers and wetlands. In such cases, helicopters are sometimes used, but this method is 20 times more expensive than using drones and causes significantly more disruption to the environment.