ALEGrO: Civil engineering concluded

26.06.2020

The cable laying work for the “Aachen Liège Electricity Grid Overlay” (ALEGrO) started in October 2018. The DC interconnector with a transmission capacity of 1,000MW will be the first direct link between the Belgian and German electricity grids and is being implemented as a joint venture by TSCNET shareholder Amprion, one of the four German transmission system operators (TSOs), and the Belgian TSO Elia. The European Project of Common Interest (PCI) provides much needed grid capacities for cross-border electricity flows and at the same time strengthens supply security in the Aachen-Cologne region in Germany and in the Belgian Liège Province. The entire binational power bridge is being realised with underground cabling exclusively.

After twenty months of construction, Amprion now has concluded the civil engineering work on the 41-kilometre-long German section of ALEGrO between the substation in Niederzier and the border to Belgium. “We have reached an important milestone even ahead of schedule,” explains Rainer Millinghaus, Head of Cable Civil Engineering at Amprion. Most of the underground cables have already been drawn into the conduits and only in some sections this still needs to be done. The converter construction site in Niederzier is also making great strides. Here, the DC from the underground cable will be converted into AC to allow connection to the German grid.

The challenging project required different types of cable installation. About 75 percent of the line was built in conventional open construction. However, obstacles like roads or railway tracks were passed with trenchless embedding techniques like horizontal thrust boring or pipe jacking. Also, a modified flush drilling method was used for the first time, which will be beneficial for Amprion in further cable projects, too. Besides these technical aspects, the implementation of ALEGrO is also state-of-the-art in terms of environmental protection: Careful handling of the soil and its hydrologic balance is ensured until the entire installation is completed. An independent soil expert accompanies the construction and recultivation, and there is also an ecological supervision.

Amprion has finished the civil engineering works for the ALEGrO interconnector (picture of Rainer Millinghaus and Theo Heitkamp from ARGE Amprion ALEGrO Aachen welding the last sleeve joint of the conduit system: Amprion)

Linkup
> See Amprion press release, in German (html)