Start of construction for Leoben substation

The "New Connection Leoben" project comprises the adaptation of the existing Hessenberg substation (municipality of St. Peter-Freienstein), the construction of the Leoben substation (municipality of Leoben), and an optimized 220kV line connection. The project’s implementation started in April 2024 and will last until mid-2026. "The project will contribute significantly to transforming the energy system without jeopardizing the security of supply and to achieving Austria's climate and energy targets since regionally generated sustainable energy can be fed into APG's trans-regional grid via the Leoben and Hessenberg substations and transported and utilized throughout Austria. In return, sustainable electricity from other regions of Austria can be brought into the region via the two substations and thus made available for businesses, industry, and society," says Christoph Schuh, company spokesperson for APG.

Following the start of the work on the Hessenberg substation back in May, construction work on the Leoben substation has now also been launched.

Technically demanding construction work

A complex terraced construction site (height difference between the different plateaus approx. 6m) had to be built into a slope. As a result, many technical challenges had to be overcome to ensure the safety of the site, explains APG project manager Wolfgang Ranninger: “The upper retaining wall, an in-situ concrete wall with a ribbed structure and permanent grouted anchors has an inclination of 75 degrees and a height of up to 20m. 189 anchor bolts had to be inserted into drilled holes of up to 37m depth. The individual anchors will have to bear a load of up to 80 tons. In addition, a 20cm thick, two-layered, reinforced shell made of shotcrete was erected to secure the areas between the individual ribs. The lower retaining wall, also with a height difference of up to 20m, is a reinforced earth wall. A total of approx. 170,000 m³ of fill material - the equivalent of around 70 Olympic swimming pools – was needed for this.”

An APG operations building with an attached switchgear system, the foundation for a 220/110 kV transformer, the necessary structures for integrating the various lines, and the required infrastructure are now being built on these terraces. A 600 m³ water tank for firefighting will also be integrated into the hillside construction. Completion and start of operation of the new Leoben substation are scheduled for the summer of 2026.

"Projects such as the “New Connection Leoben” and thus also the Leoben substation are part of APG's nine billion euro investment scheme up to 2034. In 2024 alone, we will invest around EUR 445 million in the domestic electricity infrastructure and thus in achieving the energy transition while securing the security of supply," adds Christoph Schuh.