Wind turbines use the kinetic energy of the incoming air. Modern wind power plants consist of a mast, a nacelle with the mechanical equipment, and the rotor, normally with three rotor blades. They start rotating at a wind speed of 2 metres per second (m/s). A wind power plant begins producing electricity from a wind speed of 4 m/s. The maximum power output is reached at 12 to 15 m/s. During storms, the wind turbine is usually switched off to prevent damage. The tips of the rotor blades can reach speeds exceeding 200 km/h. Electricity production depends on the wind speed (electricity production proportional to the third power of the wind speed). If the wind speed is doubled, 23 or 8 times more energy is produced.
The technology of wind turbines is relatively mature. However, there is still room for improvement, particularly in the areas of cost-effective design, production technology, overall efficiency and in operation and maintenance concepts, which result in lower production costs. The service life of a plant is between 20 and 25 years. The plant can then be repowered (replaced by a more modern, efficient plant) or dismantled. An average wind turbine consists of 60-65% concrete, 30-35% steel, 2-3% composite materials (e.g. glass fibre reinforced plastics) and less than 1% copper.
During its service life, a wind power plant generates about 40 times as much energy as was required for its manufacture, operation and disposal. The output of individual wind turbines has increased sharply over the past 25 years: Onshore (on land) from 0.5 MW to 7 MW. The choice of the power output and turbine tower height largely depends on the local wind conditions. Offshore (at sea) turbines have a capacity of 5 to 7 MW.
The Haliade-X 12 made by the US manufacturer General Electric is currently considered the most powerful wind turbine. It is able to generate around 45% more energy than any other offshore wind turbine currently available on the market. A 12-megawatt generator ensures this. As a result, offshore wind farms could operate with fewer individual turbines in the future. One of the first locations to use this wind turbine will be the port area of Rotterdam.
Axpo is Switzerland's largest producer of renewable energies. In addition to Swiss hydropower and biomass, we also use wind power at the best locations in Europe. The sustainable energy future has already begun at Axpo.
Volkswind has been a 100% subsidiary of Axpo since the summer of 2015. The German company has already installed more than 70 wind turbines with an output of over 1000 MW in France and Germany. Additional turbines with a capacity of 3500 MW are currently being developed.
Axpo is well on course in the area of wind energy. Thanks to Volkswind, Axpo has also opened up further options in the wind energy sector and established itself in a market in where it was not previously present. This offers us the opportunity to achieve higher added value from our business with renewable energies. ln addition to plant operation and marketing electricity, Axpo's business model also includes the development, construction, sale and management of wind farms.
The Global Tech I wind farm has been generating electricity for around 445,000 households far out in the North Sea since September 2015 with 80 wind turbines of the 5 MW class. Axpo has a 24.1 percent interest in this offshore wind farm. Global Tech I was one of the first wind farms to be built in the German North Sea, and is one of the so-called "far offshore wind farms" owing to its location 140 kilometres north of the logistics base in Emden.
At a water depth of 38 to 41 metres, the wind turbines excluding the rotor reach a total height of around 132 metres from the seabed. As a result, the rotor hub is thus approximately 92 meters above sea Ievel. With its three blades, the rotor has a diameter of 116 metres and covers an area the size of one and a half football fields. The tips of the rotors can reach a maximum speed of 320 kilometres per hour making them nearly as fast as today's Formula 1 racing cars.
The wind turbines cover an area of 41 square kilometres, which is just over half the size of the city of Zurich. They begin turning at wind speeds as low as 4 metres per second. They produce their peak output at a wind speed of 12.5 metres per second (45 km/h). At wind speeds of 90 km/h and more they are shut off for safety reasons.
With this commitment, Axpo aims to promote added value from renewable energies in Europe. You will find more information below in the magazine.
The Axpo subsidiary CKW (Centralschweizerische Kraftwerke AG) is involved in the wind business in Switzerland. The company has been operating a wind turbine with a gross capacity of 2.3 MW on the Lutersarni hillside (Entlebuch) since the summer of 2013. With a height of 120 metres, it is roughly the same height as the Prime Tower in Zurich and has an annual production equivalent to the consumption of 600 four-person households (around 2.5 million kWh). Another wind project on the Lindenberg on the border between the cantons of Aargau and Lucerne, which is being implemented jointly with AEW and SIG, is currently in the planning and co-determination phase.
ln Germany, Axpo owns wind farms with an installed capacity of 188 MW, in France with 151 MW and in Spain with 15 MW (Park La Penuca). Axpo also holds a 25 percent interest in the Swiss investment company Terravent with its wind farms in Germany and France.
Axpo is also active as an electricity trader in the field of renewable energies. With a volume of 14 000 MW mainly in wind energy – the company is one of Europe’s largest traders (spot market, origination and portfolio management) in the area of renewables.
More about Terravent: http://www.terravent.ch
Rated output is the capacity of the wind turbine generator at full capacity measured in megawatt hours (MW). Wind turbines reach the rated output value at various wind speeds.
Onshore wind turbines are located on land and generate wind energy from mainland wind.
Offshore wind turbines benefit from the high wind speed at sea. They are located off coastal areas. Axpo's subsidiary holds interests in 80 turbines with a total capacity of 400 MW in the North Sea.
The site defines a coherent area suitable for the use of wind energy. The site offers space for at least 3 wind turbines.
Wind energy plant refers to the wind power plant or the wind turbine. The facility transforms the power of wind into electrical energy and feeds it into the power grid.
A wind power plant comprises the following elements:
The wind farm is an arrangement of three or more wind turbines at one location.
Switzerland is not one of the typical wind countries. Nevertheless, the construction of a wind power plant could be favourable in certain locations. Although the energy produce is not predictable, relatively large quantities of electricity can be generated at economical prices with modern plants. In addition, investment in wind power is supported by cost-covering feed-in remuneration (KEV). Locations suitable for wind turbines are located on the Jura heights, as well as the foothills of the Alps and in the western midlands.
Switzerland currently has 37 wind power plants that produce around 140 GWh of electricity. The largest wind farm is located on Mont Croisin in the Bernese Jura near St. lmier. A plant comprising 16 turbines with a total output of 37.2 MW and an annual production of 70 GWh was built at this location. There are other large plants the Rhone Valley (VS), near Entlebuch (LU) and on the Gütsch above Andermatt (UR).
According to the Energy Strategy 2050, wind turbines in Switzerland will supply 600 GWh of electricity by 2020, and 4000 GWh by 2050 – around forty times more than today. In Switzerland, however, the construction of wind turbines often encounters local resistance due to noise pollution or conflicts with nature and landscape conservation. The 2020 targets have clearly been missed and the SFOE's forecast for 2050 must therefore be reduced to a wind potential of 1000 to 2000 GWh in 2050.
Map of all wind power plants: https://www.uvek-gis.admin.ch/BFE/storymaps/EE_WEA/index.php?lang=de
Federal wind atlas: https://www.uvek-gis.admin.ch/BFE/storymaps/EE_Windatlas/?lang=de