BorWin5 Onshore – De Romein GmbH Contributes to the Energy Transition

Progress of the BorWin5 Project

Major project BorWin5 for safe and low-loss transmission of green offshore power progresses – De Romein GmbH constructs onshore route from Hilgenriedersiel to Garrel/Ost converter station using egeplast Power Protect conduit system. To connect the EnBW He Dreiht offshore wind farm with 230 km between the BorWin epsilon offshore platform and the Garrel/Ost converter station, TenneT has initiated the BorWin5 grid connection project. De Romein GmbH is responsible for the civil engineering and cable installation work on the onshore route and is using egeplast Power Protect PE conduit systems for the 55 km section requiring conduits.

The BorWin5 project by TenneT Offshore GmbH comprises the construction and operation of a grid connection from the BorWin epsilon offshore platform to the Garrel/Ost converter station in the Cloppenburg district. The 320 kV DC line BorWin epsilon – Garrel/Ost (BorWin5) with a total length of approximately 230 km is complex in terms of its characteristics and consists of an offshore and an onshore section. Starting from the BorWin epsilon offshore platform, the line initially runs offshore within the Exclusive Economic Zone (EEZ) to the boundary of the 12-nautical-mile zone. From there it continues offshore to the island of Norderney, then over or under the island, subsequently through the Wadden Sea to the landfall point at Hilgenriedersiel and further along the onshore route to the Garrel/Ost converter station. The high-voltage cable system for BorWin5 consists of three cables (two power cables and one control cable), which are installed together in a cable trench.

Complexity of the Construction Project

The overall contract for the turnkey installation of the BorWin5 high-voltage cable system was awarded to NKT HV Cables AB (AG), which has already completed the civil engineering and cable installation work from the BorWin epsilon offshore platform to the Hilgenriedersiel landfall point in recent years. De Romein GmbH (AN), as a subcontractor to NKT HV Cables AB, has been commissioned to carry out the civil engineering and cable installation work on the onshore route from Hilgenriedersiel to the Garrel/Ost converter station.

Ronny Buit, De Romein site manager for the BorWin5 HDD project, provides concrete figures to illustrate the size and complexity of the construction project: “Approximately half of the approximately 110 km route will be installed in conduits, which means a requirement of approximately 110 km of pipes. This means that several truckloads of egeplast Power Protect PE 100 225 x 20.5 mm conduits must be delivered directly to the cable route each week to meet the constant demand for welded pipe strings for the six HDD rigs. The total of 45,000 excavator mats, which are laid, picked up and transported in a continuous cycle, also illustrates the scale of the project. The same applies to the 112 cable drums to be transported with a total weight of 4,500 t, each weighing 40 t and wound with two km of underground cable. All cables must first be landed at the cable hub at the port of Emden, from where they are transported by low-loader to the various drum-off sites directly along the route, where they are finally laid or pulled in as the last step.”