JDR in Nordsee One cable deal

UK energy technology developer JDR has inked a order with contractor Siem Offshore to deliver more than 70km of new-look aluminium core inter-array cabling for RWE Innogy's Nordsee One wind power development off Germany.

Under the terms of the deal, JDR will supply two lengths of cable – one 240mm-square diameter and a 800mm-square diameter aluminium conductor – both of which will be XLPE insulated for North Sea conditions.

Alongside the inter-array cables, which will be manufactured at JDR's facility in Hartlepool, northeast England, the order will include a range of accessories including cable-pulling grips and hang-offs, cable cleats, power-core termination connectors and fibre optic splice boxes.

"This project is a strategically important development for the European offshore wind market," says JDR executive vice president Paul Gahm.

"The cost-efficient aluminium core inter-array cables that have been selected for this project are the latest development in a growing JDR range of products and accessories, designed to support the long-term development of offshore wind energy production."

JDR engineering director James Young adds: "Copper is more conductive than aluminium so there are greater losses [with the latter], but aluminium is also a lot lighter so there are installation advantages there [in terms of the size and so dayrate cost of the cable lay vessel].

"For inter-array cables aluminium can be cut to fit offshore [rather than pre-tailored as is common with copper-core cables] so there are cost-savings there too."

Young notes that the aluminium cabling can be designed to be coiled, meaning more drums can be stored on the deck of installation vessels, cutting costly travel time between an offshore wind farm and an onshore supply base.

Nordsee One, located in water depths of up to 34 metres in the German Bight, is to be built around 54 turbines – originally to have been 6.15MWs supplied by Senvion until a technical fault derailed the delivery and so now being retendered – with construction slated to start early next year.

The project is part of the largest cluster of wind power developments off Germany. Together with Nordsee 2 and Nordsee 3 RWE plans to erect some 162 wind turbines with a total capacity of over 1GW spaced over 100 square kilometres at a investment cost of some €3bn.