In this series of news articles on the LIFE PowerLines4Birds project, we want to highlight the mitigation measures being implemented in the medium-voltage power grid to protect birdlife. This time, we’d like to present a solution that simultaneously mitigates the two risks to birds posed by interaction with powerlines: electrocution and collision.
For some bird species, or in some regions, there is a risk of mortality from both collisions and electrocution when they come into contact with power lines. For example, the black vulture (Aegypius monachus), the project’s target species, is vulnerable to collisions with power lines, but because of its large wingspan and its habit of perching on utility poles, it is also at greater risk of electrocution. On the other hand, in regions where there is significant overlap in the distribution of different species—each with varying levels of vulnerability to these two risks—power line modifications must include both anti-collision and anti-electrocution measures. This is the case in the Lower Alentejo, particularly in the Castro Verde Special Protection Area (SPA), where iconic species such as the Great bustard (Otis tarda) and the little bustard (Tetrax tetrax), for which mortality from collisions with power lines is one of the main threats, as well as the Iberian imperial eagle (Aquila adalberti), which, due to its large wingspan and tendency to perch on power poles, is more vulnerable to electrocution.
To respond more effectively to these situations, the PowerLines4Birds project is implementing innovative measures that simultaneously reduce the risk of collisions and electrocution on medium-voltage power lines. Given their innovative nature, these measures are being carefully evaluated not only in terms of their effectiveness in protecting birdlife but also in terms of the challenges and opportunities for their technical implementation in the power grid. In Portugal, this work has only been possible thanks to the close collaboration between the environmental NGOs (LPN, Quercus, SPEA) and E-REDES, partners in this project. Innovative measures include the eco-crossbar and the underground installation of power lines.
In terms of effectiveness in protecting birdlife, burying power lines is 100% effective! However, there are several technical and financial constraints, primarily related to the time required for the permitting process, the costs involved in this solution, and the planning of the new route. Although burying power lines is an increasingly common practice in Europe, in Portugal, current experience is largely limited to urban centers. In the Netherlands, most low- and medium-voltage power lines are buried, while in Germany, about 77% of the power grid is buried. Through the PowerLines4Birds project, we aim to expand this approach in Portugal and not only understand how to bury power lines in rural areas but also how to implement it.
In 2026, three sections of power lines are scheduled to be buried in the Castro Verde Special Protection Area (SPA), resulting in the removal of 10 km of overhead lines. These lines were selected because they pose a high risk of mortality to priority bird species in the project, particularly the Great bustard. These power lines have already been addressed in the past with other types of solutions, such as signaling devices, but the risk persists, as mortality has been observed more recently. Since the solutions implemented so far have not been effective, our only option is to bury the powerline, thereby creating safe feeding and breeding areas for various endangered steppe species. Removing these obstacles not only reduces the risk of mortality but also habitat fragmentation. In addition to the clear benefits for birdlife, burying power lines reduces the risk of damage to these structures, both due to birds’ interaction with them and due to weather events (e.g., storms). There are several known cases where a fire resulted from a bird being electrocuted on a power line, just as exposure to storms and strong winds cause power outages that affect local communities. One need only recall the storms in early 2026 that severely impacted several regions of the country, including Leiria.
However, we must also consider the constraints and potential impacts resulting from the dismantling and conversion to an underground line of an existing overhead power line. On the one hand, there are financial issues (such as the significant increase in costs compared to overhead lines), technical issues (such as creating the conditions for a transition to underground lines), and bureaucratic issues (such as the more complex and time-consuming permitting process and the need to obtain landowners’ authorization, when there is no alternative but to use public space) that pose several challenges to large-scale implementation.
Finally, there are impacts on the soil, vegetation, and animals (e.g., invertebrates), particularly during the construction phase. The impacts of the magnetic field generated by the power line on the soil are not yet known, but there are ways to mitigate these effects. In general, data on these impacts are still scarce, but this is certainly something that should be evaluated, especially as the burial of power lines becomes more common.
As an innovative initiative in Portugal, the partners in the PowerLines4Birds project are enthusiastic about both the learning process and the implementation of this measure, which offers so many benefits for birdlife. The goal is for the 10 km of power lines buried during the project to be just the beginning, and for this solution to mitigate the impact on birdlife to become commonplace.
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