NEL pipeline crosses the Elbe with Europe’s largest horizontal drill channel

Kassel. The North European Gas Pipeline (NEL) has successfully crossed the River Elbe: at the weekend a pipeline string about one kilometer long was pulled through the river Elbe from the river banks in Lower Saxony at Barförde to the other side at Boizenburg in Mecklenburg. In order to cross the Elbe, Europe’s largest underground drill channel first had to be built: 1,080 meters long and with a diameters of 1.8 meters, it runs under the two embankments and the river, which is about 300 meters wide at this point.

“We only needed about eight hours to pull the pipeline into the drill channel, which is a magnificent technical accomplishment. The pipeline string, which had to be pulled underneath the Elbe, has a diameter of 1.4 meters and weighs more than 900 tons,” senior site engineer Michael Muth explained. The connecting pipeline for the Nord Stream Baltic Sea pipeline to the west runs 440 kilometers from Lubmin through Mecklenburg-Vorpommern and Lower Saxony to Rehden south of Bremen.

A technique called horizontal directional drilling (HDD) was used to cross the river. This technique uses state-of-the-art control technology to cross the river at the precise coordinates without a trench and without leaving any traces above ground. “This way it was possible to minimize the impact on the natural surroundings, Muth explains. In contrast to other technical processes, with HDD deep excavation trenches are not necessary and the construction time is extremely short. In addition, the construction work did not require shipping traffic on the Elbe to be halted, and the integrity of the embankments was not affected.

Before the approval and construction the Lauenburg Waterways and Shipping Office, the Artlenburg Dike Association and the State Office for Agriculture and Environment of West Mecklenburg were involved in the planning for the crossing of the Elbe. “If at all possible we seek the support of the regional professional associations as they know the specific regional characteristics of sensitive pipeline segments best,” Project Manager Axel Bühning said explaining how they planned the route of the pipeline. “Along with the surveys and investigations in the areas affected, an intense consultation process at the beginning of the planning is very important.”

Construction work for the NEL pipeline began in spring of this year. More than 230 kilometers of the pipeline have already been laid and about 300 kilometers welded together. Overall, over 24,500 pipe segments about 18 meters long and weighing 15 tons each have to be laid. The natural gas pipeline is being built by the WINGAS Group and E.ON Ruhrgas. The shareholders of NEL are WINGAS (51 percent) and E.ON Ruhrgas (10 percent), as well as the Dutch gas transport company N.V. Nederlandse Gasunie (20 percent) and the Belgian network operator Fluxys G (19 percent). The planned investments for the pipeline project are around one billion euros. The NEL pipeline will have a transport capacity of around 20 billion cubic meters of natural gas per year, which is roughly equivalent to a fifth of Germany’s annual consumption of natural gas.