Danish giant Dong Energy and Swedish energy company Vattenfall have agreed to cooperate on a common project that can link their respective Horns Rev wind farms.

These two wind farms are located in the Danish North Sea.

As part of this project, the companies have started a project that can ensure emergency power supply for Dong’s Horns Rev 2 and Vattenfall’s upcoming Horns Rev 3 offshore wind farms, in case, if their respective export cables to the land fail.

While Dong Energy’s Horns Rev 2 generates 209MW of clean electricity, Vattenfall’s upcoming Horns Rev 3 is expected to generate about 406MW of clean energy.

With this project, both the companies say that their billions of DKK of investments are secured. The project will facilitate in supplying emergency power for each other’s wind turbines.

Vattenfall stated that failure of export cables not only disrupts electricity to consumers on the mainland, but can also bring problems to the turbines as well. All the turbines must always have power to keep their blades in correct positions in relation to the wind direction.

Vattenfall project manager Niels Møller Jensen said: "Emergency power for the wind turbines normally comes from one single large, centrally located generator on a platform at sea.

“At Horns Rev 3, we’ve chosen to install a small generator in each of the 49 wind turbines and, as something new in the industry, we’ve made an agreement with DONG Energy that we install an 8km long 33kV cable between Horns Rev 2 and Horns Rev 3, thereby establishing a connection between both wind farms."

Niels Møller Jensen also stated that such an agreement could prove to be an economic and environmental way to secure emergency power supply to each other’s wind farms. Installation of small diesel-powered generators at the wind turbines at Horns Rev 3 is expected to ensure uninterrupted power supply for a few days until the company can know how long a potential power failure will last.

DONG Energy Asset Management 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."

Image: Dong Energy and Vattenfall to link up Horn Rev offshore wind farms. Photo: Courtesy of DONG Energy A/S.