Dong Energy, Vattenfall cooperate for emergency power supply for wind projects

Dong Energy has collaborated with Vattenfall Vindkraft to initiate a common project to provide emergency power supply for Horns Rev 2 and Horns Rev 3 offshore wind farms in the North Sea in Denmark.

The Horns Rev 2 offshore wind power project is owned by Dong Energy, while the upcoming wind farm Horns Rev 3 is owned by Vattenfall.

The two companies have entered a mutual agreement to supply electricity in case of emergency to each other's wind turbines if their respective export cables to land fail.

Vattenfall project manager Niels Møller Jensen said the failure of export cable not only affects the supply of electricity to customers on the mainland but a cable outage is also critical to the wind turbines.

The Horns Rev 3 wind farm will be installed with a small generator in each of the 49 wind turbines.

The company has partnered with Dong Energy to lay an 8km-long 33kv cable between the two wind power projects to establish a connection between both the facilities.

Dong Energy Asset Management region head Leif Winther said: “We see the cooperation with Vattenfall on the emergency power supply as a good guarantee for both wind farms, which keeps the wind turbines in good condition so that they can start producing again really quickly once the fault is corrected and in addition, it’s a relatively small investment in an emergency power cable if one looks at the total cost of an offshore wind farm.”

The small diesel generators in the wind turbines at Horns Rev 3 will supply power for a few days until Vattenfall knows how long a potential power failure will last.

If it lasts longer, the electricity supply from Horns Rev 2 can provide emergency power to the wind turbines on Horns Rev 3 until the export cable is back in operation.

The same process will be followed for the other way.

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Image: Dong Energy's offshore wind farm, Horns Rev 2, will in the future ensure emergency power supply for Vattenfall's upcoming Horns Rev 3. Photo: courtesy of Dong Energy.