*Update* E- Power Pipe te Oirschot
Last week we pulled the last 2000 meter bundle of cables into the borehole carried out using E-Power Pipe. This brings this project to an end for Denys and Kouwenberg Infra. It was a beautiful, challenging, educational and above all successful journey on which we look back in its entirety below.
On October 7, 2020, Kouwenberg Infra and Denys partnered to realize the first E-Power Pipe (EPP) project in the Netherlands. Not only was this a unique project, but also this new system developed by Herrenknecht had not yet been drilled beyond 670 meters. For TenneT and NRG, however, we gladly accepted the challenge of using the EPP system to drill a 550-mm diameter well of no less than 2000 meters! A project part of the realization of a 150kV underground cable connection between the distribution stations in Tilburg Noord and Best.
Not only the drilling would be our part, also the pulling of the bundle of cables with diameter 431 mm over the same length was part of the work to be carried out. In short, enough challenges to sink our teeth into.
The preliminary investigations had already been carried out by TenneT, but there was still plenty for us to prepare in order to ultimately realize a successful drilling. We wanted to make sure that the system would be able to pump 2000 meters of drilling mud. Therefore, a successful full-scale test already was carried out by Herrenknecht and the conceived theory was made plausible.
The subsoil in which to drill was also examined and the most ideal soil layer to drill in was considered. The minimum coverage required was determined with Prysmiangroup with the requirement that the heat from the cables could be sufficiently dissipated into the surrounding subsoil. It was concluded that the cables should be laid with a minimum ground coverage of 2 meters. With this in mind, we continued with the design, and the next step was to investigate the tree roots present; after all, the drilling was to take place in the middle of the Oirschotse Heide forest near Oirschot. We investigated with experts whether the drilling was likely to hit tree roots. Not nice for the machine and certainly not nice for the trees involved.
Now it was time to make the shafts. A pressure pit made of sheet piling and a receiving pit using a trench box. All four borings could be carried out in two directions from the pressing pit. The first to go was two times 400 meters. The drilling teams of Kouwenberg and Denys worked very closely together with the drilling specialists of Herrenknecht. It was decided to drill using a continuous process. The first two drillings were successfully completed within the set parameters. Knowledge of the for most of us new machine was gained and the teams were well adjusted to each other. A number of improvements were also made to the drilling process; time for the real work!
The challenge now became not only drilling 2000 meters with 2 meters ground cover, but also drilling with a horizontal and vertical arc radius. From previous experience, we knew we had to succeed, but that was just theory. Fortunately, theory and practice turned out to go hand in hand here and both drillings were carried out in accordance with the set requirements.
This was a successful implementation of a new trenchless technique for laying pipelines at shallow depths with minimum disruption to the surrounding area, with which the pipelines are still easily accessible. A good solution for the many kilometres of cable still to be laid as part of the energy transition. Someone was already talking about the next challenge of 5,000 meters. We are ready for it!