One of the biggest challenges of the energy transition is connecting decentralised green energy sources to the onshore power grid. Connecting offshore wind farms to the grid, in particular, involves considerable time, construction work and financial expenditure. Trenchless technology can reduce these efforts, bringing power ashore by the shortest route without damaging sensitive coastal landscapes. As with the BalWin1 and BalWin2 offshore grid connection systems. These cable routes run through the Wadden Sea National Park and the protected dune landscape of the island of Norderney, with some sections being installed using horizontal directional drilling (HDD). A GRUNDORAM TAURUS steel pipe rammer plays a small but crucial role here. BalWin1 and BalWin2 are two of the four grid connection systems operated by the transmission system operator Amprion. They run from wind farms in the North Sea, via two converter platforms under the East Frisian island of Norderney, to the mainland at Hilgenriedersiel. Each system consists of three parallel DC cables and has a transmission capacity of 2000 megawatts — enough electricity for around four million people. The contractor, LMR Drilling, must carry out 18 horizontal bores to install protective pipes into which the submarine cables will be pulled later. Construction work will be carried out in three phases: In summer 2025, six HDD bores will be made from the centre of the island towards the southern mudflats and the mainland. In 2026, drilling will continue from there northwards in the direction of the offshore converter platforms. In 2027, the mainland dyke will be crossed. As the sandy soil at the start of the HDD bores is highly unstable, theGRUNDORAM TAURUS is being used to drive casing pipes into the drillable layers at the entry points for guidance. Everything about this construction project is huge: the construction site ‘At the lighthouse’ on Norderney covers 14,000 m? and has an additional 8000 m? of storage space. It is surrounded by a 257-metre-long, 10-metre-high noise barrier. In addition to forklifts and excavators, two heavy-duty cranes are used to transport materials and equipment. The maxi HDD drilling rigs being used have thrust and pull forces of 250 and 450 tonnes, respectively. The south-facing bores on Norderney are 1010 metres long and the north-facing ones are 1140 metres long. There are seven water tanks with a total capacity of 850 litres on site for mixing and storing the drilling fluid. To install the pipes and transport materials from the southern mudflats, two huge platforms, known as pontoons, have been anchored there. The casing pipes through which HDD drilling starts on land have a diameter of 800 mm and each one is 24 metres long. Given these dimensions, the 4-metre-long, 4800kilogramme TAURUS rammer from TRACTO seems almost small. Pneumatically driven ramming machines Pneumatically driven ramming machines are most used in pipeline construction for 28 HYDRAULICS & PNEUMATICS March 2026 www.hpmag.co.uk Offshore wind projects require complex infrastructure to bring power safely to the onshore grid. Pneumatic pipe ramming technology is supporting trenchless installation methods that enable cable landfalls while minimising environmental disruption. H&P reports. KNOWLEDGE BASE Pneumatic pipe ramming supports offshore wind grid connections The compressed air-powered TAURUS pile driver during the driving of a steel pipe. Image courtesy of TRACTO ©TRACTO
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