The foundation for the world’s deepest offshore wind turbine has just been installed 17 miles off the coast of Scotland. Last week, the roughly 441,000-pound “jacket,” or foundation, was placed at a depth of 58.6 meters—just over 192 feet—by the Sapiem 7000, the world’s third largest semi-submersible crane vessel. It was the 112th jacket installed at the 114-wind turbine Seagreen wind farm, which will be Scotland’s largest when it is fully operational later this year.
Wind turbines like these work like an inverse fan. Instead of using electricity to generate wind, they generate electricity using wind. The thin blades are shaped like aircraft wings and as the wind flows across them, the air pressure on one side decreases. This difference in air pressure across the blade generates both lift and drag, which causes the rotor to spin. The spinning rotor then powers a generator, sending electricity to the grid.
Offshore wind farms like Seagreen have a number of advantages over land-based wind turbines. Since wind speeds at sea tend to be faster and more consistent than they are over land, it’s easier to reliably generate greater amounts of electricity. Even small increases in wind speed can have a dramatic effect: in a 15-mph wind, a turbine can generate double the amount of electricity it can generate in a 12-mph wind.
Also, coastal areas frequently have high energy requirements. In the US, more than 40 percent of the population, some 127 million people, live in coastal counties. By generating power offshore close to where it’s used, there is less need for long-distance energy transmission, and cities don’t have to dedicate already scarce space to power plants.
But of course, the biggest advantage of any wind farm is that they can provide renewable energy without emitting toxic environmental pollutants or greenhouse gasses. They don’t even need or consume important non-petrochemical resources like water, although they can have other environmental impacts that engineers are trying to solve for.
The recently installed foundations at Seagreen will each support a Vestas V164-10 MW turbine. With a rotor diameter of roughly 540-feet—that’s more than one-and-a-half football fields—and standing up to 672 feet tall—more than twice the height of the Statue of Liberty—these turbines will be absolutely huge. Each one will be capable of generating up to 10,000 kilowatts (KW) of power in good conditions.
Although Seagreen actually started generating electricity last summer, when the wind farm is fully operational later this year, the 114 wind turbines will have a combined total capacity of 1,075 megawatts (MW). While that’s not enough to crack the top 100 power stations in the US, the wind farm is projected to produce around 5,000 gigawatt hours (GWh) of electricity each year, which is enough to provide clean and sustainable power to more than 1.6 million UK households. That’s around two-thirds of the population of Scotland.
Really, the Seagreen site shows how far wind power has come. While wind farms don’t yet have the capacity to fully replace fossil fuel power plants, Seagreen will still displace more than 2 million tonnes of carbon dioxide that would otherwise have been released by Scottish electricity generation. According to Seagreen, that’s the equivalent of removing a third of all Scotland’s cars from the road.