Extraordinary high-voltage line construction for a strategic project in Salzburg
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In a mountainous environment, operating under environmental constraints, and with privately owned land to be managed, the Salzburg high-voltage line project Omexom delivered in May 2024 was one of a kind, and crucial to Austria’s energy transition.
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Construction of the Salzburg high-voltage line between 2019 and 2024 was the largest electricity infrastructure project in Austrian This new line is key to the country’s energy transition and to achieving its climate and energy targets.
From 2030, Austria hopes to meet 100% of its electricity needs from low-carbon electricity, which means finding around another 27 terawatt-hours of energy. Only powerful electricity networks can ensure an efficient transfer between the excess wind energy produced in eastern Austria and the storage facilities located in the west. Which is where the Salzburg line comes in, delivered in May 2024 and providing seven times more transmission capacity. The project was unique in many respects.
An exceptional project
Appointed by the national network operator – Austrian Power Grid – to handle this project, Omexom – the VINCI Energies energy infrastructure brand – had to adapt to the unique features of an Alpine environment and numerous considerations arising from private land ownership.
“The route of the Salzburg line was a unique challenge in itself,” says Jens Schulz, Division Manager Overhead Line Construction at Omexom Hochspannung (Germany, Austria, Northern Italy). “We also had to follow strict environmental protocols and implement offsetting measures to minimise the impact on the environment and on local residents, from the first day of construction and throughout the line’s lifetime.”
These constraints were all the more difficult to manage given the extraordinary scale of the project, with the construction of 76 towers – some over 100 metres tall, the dismantling of two existing 380 kV towers, and the construction of a temporary 220 kV tower to maintain the power supply to the Salzburg substation during the works period.
Upon completion of the project in May 2024, 22.3 kilometres of new overhead lines had been installed and 1.7 kilometres of existing lines modified. The literal high point of this atypical project was the assembly of the Nockstein tower at 915 metres above sea level, which at 34.40 metres high and 42.20 metres wide, and weighing 111.69 tonnes, represents a major technical achievement, and its design – by a specially selected architect – has created a unique, and now iconic, structure for the region.
Technical and environmental challenges
As the general contractor, Omexom was also responsible for auxiliary works, such as road construction, foundations and landscaping.
“The route of the Salzburg line was a unique challenge in itself”
“Since many of the towers were in mountainous terrain, we were working in areas where any access routes, if they exist at all, are strictly regulated,” explains Jens Schulz. “We were therefore unable to bring in the heavy machinery we generally use to assemble and install electrical lines, or to erect the towers pre-assembled.
We had to design special cableways between 100 and 150 metres long to supply materials and technical equipment to the tower locations”
Time management was also a challenge. Because some of the towers and access routes are on private land, time for negotiations with the landowners had to be factored into the project schedule. The Omexom teams also had to adapt to natural rhythms, in this case those of small amphibians, reptiles, and birds such as the Western capercaillie, an endangered local species. Not to mention the local hunting season, which limits construction activity in the area during July and August.
“During the works, more than 17 kilometres of amphibian fencing were installed,” says Jens Schulz. “We created more than three dozen ponds around the tower sites. These ponds, measuring between 25 and 500 sq. metres, provide a new habitat for local flora and fauna. In addition, all the way along the work zone, we transformed dead wood into shelters for insects, reptiles and small mammals.”
Austrian Power Grid allocated approximately €47 million to conservation measures during the construction period and throughout the project’s lifetime. Altogether, almost 200 offsetting measures for flora and fauna were implemented across some 1,100 hectares.
In the long term, the Salzburg line will represent a significant improvement on the current infrastructure, with 65 fewer kilometres of lines and 229 fewer towers, bringing real benefits for local residents and for nature.
Key Figures
22.3 kilometres. Length of the new overhead lines created by Omexom as part of the Salzburg high-voltage line project.
915 metres. Elevation of the Nockstein tower, a structure 34.40 metres tall and 42.20 metres wide, weighing 111.69 tonnes.
200. Number of offsetting measures for flora and fauna implemented across some 1,100 hectares
€47 million. Budget allocated to conservation measures during the construction period and throughout the project’s lifetime
07/15/2025
