Good Terms With The Neighbours

The owners of the two offshore wind farms Horns Rev 2 and Horns Rev 3 Ørsted and Vattenfall have jointly invested in the 33 kV cable to provide additional safety for their wind farms in the North Sea. An export connection problem to land wouldn't only affect the electricity supply to customers on the mainland, but also the offshore wind turbines.

“Offshore wind turbines must always be supplied with electricity; otherwise there is a risk of significant damage from for instance humidity. The cable also enables a quick and easy start-up of the offshore wind farm once the export connection is back in service. In addition, we save a lot of diesel fuel and operating hours for the emergency generators for both the wind turbines and the service boats”, points out Niels Møller Jensen, Interface Manager at Horns Rev 3.

The cable, which was completed in April, is an optimal solution in terms of both the environment and investment and operating costs. It was recently used for the first time when Danish grid operator Energinet had to disconnect the Horns Rev 2 export cable for four days for maintenance. During this time, the wind farm was supplied with electricity from Horns Rev 3.

“We are really happy that we could supply our 91 wind turbines with back-up electricity from Horns Rev 3 during Energinet’s planned inspection of the export cable’s high voltage switch. Thanks to the new cable, we were able to resume generation of green power much faster”, says Allan Due Overbeck, Head of Operations Horns Rev 2.

The wind turbines at Horns Rev 2 usually receive emergency power from a central generator on an offshore platform. With Horns Rev 3, each turbine has a small emergency generator.