"With this project, we help to take the energy turnaround another step forward and make it possible for offshore wind energy to make an important contribution to our future energy supplies", says Lex Hartman, member of the board of transmission system operator (TSO) TenneT. "With DolWin3 included, we will be able to supply a total of more than 6,000 MW of clean energy from the North Sea – and we will be investing more than €7 billion in the energy turnaround."

DolWin3 is the eighth grid connection project to be implemented by TenneT using direct current (DC) technology. Together with three projects based on AC current technology, the TSO responsible for the North Sea will then deliver a total of around 6.2GW of offshore wind energy to the mainland. The DolWin3 project will be the third grid connection in the DolWin wind farm cluster in the south-western region of the North Sea and will offer a capacity of 900MW. The project will be completed in 2017.

As the general contractor for TenneT, Alstom will supply and construct both the onshore and offshore converter stations as well as the connecting cable systems for DolWin3. The project will use DC technology (with Voltage Source Converters; ±320 kV, 900 MW) to deliver the energy generated at sea down an 83km sea cable to the mainland. From the coast, the wind power will then be transported a further 79km via anunderground cable to the converter station in Dörpen/West in Lower Saxony (Germany). The grid connection will be supplied as a turnkey solution by Alstom.

Alstom has also been awarded a five-year service contract covering the complete offshore converter station and platform, as well as the onshore converter system. The contract includes inspection, preventive and corrective maintenance, refurbishment and repair, spare parts management and a technology support line.