The project
The Elbe crossing is an important element of the SüdLink megaproject to construct a powerful high-voltage direct current (HVDC) transmission line. This will transport electricity generated from wind farms in the windy north of Germany down to the south of the country. The HVDC cables will primarily run underground, so the cable between Wewelsfleth and Wischhafen will have to pass through a 5.2 km-long tunnel under the Elbe River. PORR has been tasked with constructing this tunnel, including excavating the construction pit and securing it with diaphragm walls, underwater excavation, hydro-shield tunnelling with segmental lining and establishing all operations buildings and transmission infrastructure.
PES in the thick of it: Turning challenges into requirements
A project as complex and challenging as this creates extreme demands in terms of the equipment and machinery required. In addition to standard tools and equipment, the project also has very specific requirements that PES must meet.
Let’s look at a few examples:
A new cable excavator urgently had to be procured to construct the diaphragm walls that stabilise and secure the construction pit. The project is using a diaphragm wall grabber operated with a cable excavator. PES has supplied a Liebherr HS 8130.1 for the ElbX project with a rated motor output of 565 kW along with two winches, each capable of producing 350 kN of traction force. The grabber has a maximum lifting capacity of 130 tonnes.
Barely a week after the excavator arrived on site, work began to construct a trial diaphragm wall. Delivery was delayed by a few days because special transport arrangements were required, including a police escort.
At the client’s request, PES provided electric vehicles to ensure that the project managers and the client could travel conveniently between the various sites and shafts. PES opted for four Atto 3 compact SUVs made by Chinese manufacturer BYD.
Sustainability is a top priority on the SüdLink project. Electrical machinery was an obvious choice as a sufficient power supply was available. PES has been examining potential electric alternatives to conventional construction equipment with combustion engines for some time. In addition to sustainability, of course, cost efficiency is another factor that requires careful cost comparisons. In the passenger car segment, a number of models are now available in different price segments on the market, with plenty of experience-based figures available. In situations where electricity is available cheaply or even free of charge, electric vehicles have a clear advantage over cars with internal combustion engines – not only in terms of their carbon footprint but also from an economic perspective.
PES also engages intensively with the topic of e-mobility away from its activities on individual construction sites. Unlike on the ElbX project, electricity is only available for vehicle charging on public roads to a limited extent and can sometimes be expensive. The majority of the extensive vehicle fleet that PES provides for the PORR Group is solely intended to ensure that our employees can travel where and when needed. Foremen, site supervisors and project managers often oversee several construction projects in parallel, which means they rack up significant mileage and do not always have convenient access to charging facilities. A more widespread shift to e-mobility will require significant improvement in the availability of charging facilities, especially in more remote areas. In addition to the high initial purchase costs, the high charging costs mean that the sale of EVs often lag behind that of cars with conventional drive systems.
