Much of this technology has been in offshore wind turbines, mainly in the North Sea. At sea, both space and wind are more plentiful, making it more economical to build larger machines. The best example is MHI-Vestas’ V164 wind turbine, currently the largest wind turbine on the planet. Capable of producing 9.5MW, it can power around 8,000 domestic homes. Compare that to just 15 years ago when the biggest machines produced around 2.5MW.
And just how big is the V164? The blades are 80 metres long. The nacelle (that’s the box at the top of the tower) is over 20 metres long and comes equipped with its own crane.
A wind turbine is essentially just a generator. A device called a yaw control, which detects wind direction, sits on the nacelle, ensuring the turbine faces the wind at all times. As the blades turn, they power a generator inside the nacelle which produces electricity. Should the wind blow too hard, a brake is applied to the blades, which are then turned so as to avoid catching the wind. Just as well since turbines can explode if too much power is produced.
The reason for the growth of wind power is simple: we need electricity, and lots of it. Carbon reduction targets have resulted in the closure of power stations fuelled by fossil fuels, while electrical vehicles and heating systems cry out for ever more energy.
Currently the biggest offshore wind farm on the planet is the UK’s 630MW London Array, in the estuary of the River Thames. A number of future projects, however, will soon dwarf this. One of these is Hornsea, developed by Siemens and Orsted, in the North Sea, off the UK coast. It will cover an area of 1,800 square miles (4,730 square kms) and be capable of producing 4,000MW.