Offshore wind farms such as the Gemini farm benefit from higher wind speeds but, unfortunately, have to be built in relatively shallow waters. With floating turbines, on the other hand, energy can also be generated in locations where the sea is deeper. One such floating wind farm has recently been commissioned off the coast of Scotland.
The wind turbines of this Hywind farm float about 25 km off the shores of Aberdeenshire and have a capacity of 30 MW, enough to power about 22,000 homes. The park is spread over an area the size of 4 square kilometres and consists of five 6-MW turbines that have a height of 253 m. At that height, the wind speed averages 10 m/s.
Although the wind farm certainly does not provide the most power, floating turbines can be deployed in water up to 800 m deep, which is about 10 times more than fixed turbines. The number of possible locations where these floating variants can be deployed is thus many times larger.
The Hywind turbines float on water with depths ranging from 95 to 129 m. Each of the turbines is stabilised with three anchors. The turbines are interconnected and the energy they produce is transmitted to the coast 30 km away via 33 kV cables. Although the Hywind farm is relatively small, it aims to demonstrate the potential of this technology. According to initiator Statoil, offshore wind farms will play an important role; much of the offshore wind energy potential can only be extracted at locations where fixed installations are not possible
