The winter period of operation of the world’s first floating wind farm Hywind, which started operating last October off the coast of Scotland, showed its greater efficiency compared to conventional onshore “wind turbines. According to ArsTechninca, the power plant, located 25 kilometers off the coast of Aberdeenshire, Scotland, has shown a capacity factor of 65% from the moment of launch to the present. Statoil, which owns Hywind, claims that conventional onshore wind farms show 40 to 60 percent efficiency in winter.
A power plant’s capacity factor is the ratio of its output to its maximum rated output. The Scottish Hywind wind farm has a capacity of 30 megawatts. A capacity factor of 65% means that the average capacity of the station during the winter period of operation was 19.5 megawatts. The winter period is considered the most prosperous period for wind farms in terms of power generation. It is during this period that frequent and strong winds blow on the coast.
The annual output of the Hywind wind farm is not yet known. It will probably be calculated at the end of this year. According to the U.S. Energy Information Administration, U.S. onshore wind farms had a capacity factor of 36.7% in 2017. By comparison, the same figure for solar power plants over the same period was 27 percent and hydroelectric plants 45.2 percent. It should be noted that nuclear power plants have the highest capacity factor of all. For them, it averages 90.4 percent.
The Hywind floating power plant consists of five wind turbines. Each generator is installed on a mast 175 meters high mounted on a 78-meter long stabilized float. Such a float allows the wind turbines to be placed at a distance from the shore in water depths of up to 800 meters. Wind turbine floats use iron ore as stabilizing ballast. In addition, the float is held underwater by three flexible cables secured to the bottom with heavy 60-ton blocks. The weight of one wind turbine is about 12 tons.
“Wind turbines are equipped with propellers with three blades, each of which is 75 meters long. The installation angle of the propeller blades of the wind turbine can vary. It is determined by the special control software, which calculates the right angle depending on the strength of the rocking and wind. Eventually, the floating power plant in Scotland will be equipped with a one-megawatt-hour lithium-ion battery that will take on peak electricity consumption.
In the middle of last year, the Makani division of the U.S. company Google tested a wind turbine made in the form of a cordon glider. The new flying wind turbine will have to hover at altitudes where there is almost constant wind and produce electricity. The apparatus, which looks like a glider with a wingspan of 5.9 meters, will be connected to the ground with a special cable and rise to a height of 305 meters. The device is equipped with eight small generators connected to propellers with a diameter of 2.3 meters each.