Earlier this week, system operators Elia and Amprion inaugurated the first electricity interconnector between Belgium and Germany, ALEGrO. Our Belgian entities Franki Foundations & Van den Berg made this historic moment possible as they were respectively responsible for the foundations of the Lixhe conversion station and the underground DC installation.
ALEGrO (Aachen-Liège Electric Grid Overlay) is the first electricity link between Belgium and Germany, connecting the two countries' high-voltage grids. The project aims to enhance both countries' security of supply and facilitate the integration of renewable energy sources.
ELIA has developed the Belgian part of this project, which consists of two parts: an underground link between the Lixhe station (in Belgium) and the German border and the Lixhe conversion station that connects the ALEGrO link (DC) with the existing grid (AC).
49km of cables by Van den Berg
As a subcontractor to General Cable, Van den Berg played a vital role in the underground DC installation. Part of BESIX Group, the entity specialises in cable and pipe laying for various infrastructure projects throughout Belgium.
The 49 km of cable-laying on Belgian territory, including a tunnel under the Albert Canal and the River Meuse, was carried out entirely by Van den Berg. For the 670-metre-long tunnel, it partnered up with Jan De Nul and K-Boringen.
The total underground electricity link is around one hundred kilometres long. In this project, Van den Berg used horizontal directional drillings (HDD) to bore 35 holes from 70 to 450 metres long, many of them through rock. 94 reels of cabling were used, with an average weight of 40 tonnes. In all, 40,000 tonnes of dolomite were processed in the total project.
Over 5,200 ballasted columns by Franki Foundations
Franki Foundations was commissioned by Siemens to build the foundations for the Lixhe conversion station (Belgium), including site installation, earthworks in the undeveloped surrounding area, construction of the platform and soil improvement by means of ballasted columns. Franki Foundations are BESIX Group’s go-to experts for all deep foundations projects in Belgium and abroad, via its subsidiaries.
For ALEGrO, the Franki Foundations teams placed more than 5,200 ballasted columns. The soil at the site is multi-layered, including a hard layer at a depth of approx. 4 metres. The ballasted columns are anchored in this hard layer, to avoid excessive differential settlement under the weight of the future conversion station.
The ballasted columns are formed by displacing the soil laterally using an electric (or hydraulic) vibrating needle lowered down to the hard layer. The space created this way is then filled up with gravel and compacted to produce a ballasted column. This lateral displacement improves the mechanical properties of the soil between this mesh of columns.
Exchanging 1 GW of renewable energy
Now ALEGrO has been put under full load, it can successfully transmit 1,000 MW in both directions (approximately equivalent to the electricity consumption of a city with a population of one million).
This project is a new step towards a more balanced and secure electricity supply of the Belgian network. The connection with Germany is also seen as an important missing link to transport renewable energy from Germany to Belgium.
Thanks to the excellent groundworks of the BESIX teams, we’re proud to be part of this sustainable solution for a better world.
