Offshore wind farms like the Gemini facility in the Netherlands can tap into the higher average wind speeds over the ocean, but unfortunately these facilities can only be built in relatively shallow water. Floating turbines can help harvest wind energy from above deeper waters, so to that end, the world's first floating wind farm has just fired up off the coast of Scotland.
Floating some 25 km (15.5 mi) off the coast of Aberdeenshire, Scotland, the Hywind farm has a capacity of 30 MW and will supply power to about 22,000 homes. Spaced over an area of about 4 sq km (1.5 sq mi), the farm is made up of five 6-MW turbines that stand 253 m (830 ft) tall, taking advantage of average wind speeds of 10 m (33 ft) per second.
While this pilot facility is a far cry from the 630-MW London Array, the world's largest offshore wind farm, it does have a key advantage: its floating turbines can operate in water up to 800 m (2,625 ft) deep, 10 times deeper than the upper limit of fixed facilities. That drastically widens the net of viable locations for offshore wind farms, a technology with incredible energy-generation potential.
The Hywind turbines are floating in water between 95 and 129 m (312 and 423 ft) deep, each one stabilized with three suction anchors. They're all linked together, and the energy they produce is exported to shore through a 30 km (18.6 mi) cable at a voltage of 33 kV.
While it's still relatively small, the Hywind facility is intended to demonstrate the feasibility of the technology, eventually paving the way for floating wind farms that are more than 10 times bigger.
"Statoil has an ambition to reduce the costs of energy from the Hywind floating wind farm to €40 - 60/MWh (US$47 – $71) by 2030," says Irene Rummelhoff, executive vice president of New Energy Solutions at Statoil, the company operating the farm in partnership with Masdar. "Knowing that up to 80% of the offshore wind resources are in deep waters where traditional bottom fixed installations are not suitable, floating offshore wind is expected to play a significant role in the growth of offshore wind going forward."