PAS System for Bird-Friendly Grid






EVN Bulgaria (Elyug) implemented bird-friendly power lines involving the insulation of components of the grid infrastructure and the installation of additional elements to overhead power lines in order to protect both the lines and specific bird species. The practice is part of the Life for Safe Grid project (life 12 NAT/BG/000572) funded by the Life Programme of the EU.



  • Prevent the collision and electrocution risks for the imperial eagle “Aquila heliaca” (primary target) and other bird species
  • Enhance the security of the grid and the supply of electricity by preventing disruptions caused by bird incidents


Main information:

The insulation of power lines is a common practice for bird protection. However, PAS system is innovative as it combines various protective measures in one holistic system in an efficient and bird-friendly way. It is composed of the following elements: wire, insulation coating on the line (weatherproof synthetic VPE material), insulated parts (fittings, connectors to the pole, consoles) and protective elements, such as perches, that provide a higher and safer place for birds to rest, and wing space diverters, that ensure a gap between the pole and the place available for birds to perch.

The practice was first implemented along a 15 km stretch of the overhead power line “Balgarin”. The line passes across the Sakar Special Protected Area (SPA), which is part of the Natura 2000 network and the most important SPA for the Imperial Eagle in Bulgaria, holding 10 breeding pairs and supporting the young birds during their dispersion period. The Imperial Eagle is classed as one of numerous vulnerable species according to the Red list of Threatened Species. Unnatural mortality caused by aboveground electric infrastructure has been proven to be the major threat for juvenile and immature Imperial Eagles in Bulgaria. In the period 2009–2012, over 78% of all juvenile eagles have died as a result of electrocution. PAS evaluation of the effect on bird mortality will be undertaken in 2018, but the first results indicate reduced disturbances on the grid since the implementation of the line, which is a great indicator of success regarding the protection of both the birds and the line.


Additional information:

  • EVN Bulgaria Elektrorazpredelenie is an electricity distribution company that operates in South-East Bulgaria and provides electricity for more than 1,5 million customers. The company operates in an area of nearly 42,000 square kilometres
  • The practice is part of the activities of Life for Safe Grid project funded by the Life programme of the European Commission. The activity was planned in cooperation with the partner in the project, the Bulgarian Society for the Protection of Birds (BSPB) and takes place in eight protected areas within the Natura 2000 network in Bulgaria


RGI gratefully acknowledges the EU LIFE funding support:

EU LIFE funding support Logo

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the LIFE Programme. Neither the European Union nor the granting authority can be held responsible for them.