Where do wind turbines come from? A little bit of Norway and a lot of mating.
Read more: The floating wind turbine that thinks it's a blimp
In 2009, a wind turbine was constructed in Karmøy, Norway. An unusual prototype, it was built upon flat ground but was not anchored to the land. Instead, it was lifted up and set down upon a floating anchor in the North Sea.
In 2017, this prototype has come to fruition - destined to be anchored off the coast of Peterhead, Scotland to create the world's first floating wind farm, a £200m project known as Hywind.
The creation of the first electricity-generating wind turbine in 1888 in Ohio changed how we think about energy, but this was confined to land, subject to restrictions of acreage and lower wind speeds. Modern advancements in engineering have allowed us to move this technology from land to sea in an elaborate construction process that spans across countries.
Compared with bottom-fixed installations, Hywind Statoil floating turbines are designed to be deployed in deeper waters of more than 100 metres, further away from shore, where winds are stronger. A spar buoy forms the floating component, large enough to carry the weight of the turbine as well as withstand up to 20m waves. To maintain its equilibrium, the buoy is filled with 8,000 litres of sea water and ballast to make it stay upright.
Each buoy weighs approximately 46,000 tonnes and can only be transported by the world's heaviest transport vessel – the Dockwise Vanguard. Capable of carrying 110,000 tonnes, the Vanguard is a semi-submersible heavy lift ship that can sink partway under water to hulk vast machines across oceans.
Once these pieces come together, the final phase of development begins – the aerial suspension of a turbine across the water.
The sight of a wind turbine suspended in the air is an unprecedented feat of engineering, lifting it out across the ocean and setting it down upon a buoy. Aligning these mechanisms of the turbine and substructure to link them together in a process known as "mating". This mating is an historic event and a close-up of the operation reveals that it relies upon a three-line mooring system to secure the turbine to its buoy. Once this is complete, the five turbines are ready to begin life upon the water, towed to Buchan Deep, 15 miles offshore of Peterhead in Scotland.
Waters that are shallow enough for fixed turbines are few and far between, whereas the ocean presents a vast area in which to build floating turbines. The Hywind farm has the capacity to generate 30 MW of electricity – powering roughly 22,000 households.
Currently, the UK is the world’s largest offshore wind market and accounts for just under 36 per cent of installed capacity, followed by Germany in the second spot with 29 per cent. In some countries, offshore wind is now cheaper than onshore wind, prompting renewed investment in the industry. This is due to a number of factors, including the development of newly designed turbines such as the 6MW models used in the Hywind project, to increased investor confidence in markets across the globe, such as China and Taiwan.
The Hywind project is due for completion at the end of 2017. Until then, the turbines will have to endure a journey across the sea from Norway to Scotland, in a daring feat of renewable engineering.
This article was originally published by WIRED UK
