How do wind turbines generate electricity

Wind turbines are becoming more powerful. Especially at sea could soon giants with up to 20 megawatts and 280-meter rotor diameter be set up. Of today’s systems, they are clearly distinguishable.

It was just over a quarter century, when the barren hills of southern California showed a sudden growth. As a landscape architect, the Riverside County around Palm Springs for a giant installation was selected, were ridges and slopes in the 1980s, covered with a forest of white rods at their tips turned three wings wheels: Supported by a funding program of the State of California created thousands Wind power plants, including many of the type M108 of the then Danish manufacturer Micon. They provided 108 kilowatts of power and laid the foundation stone for the soaring wind energy.

With a nearly 24 meter high tower and a rotor diameter of 19 meters Micon M108 was considered a true giant among the wind turbines. But through the years, the plants became larger and larger. Today impress the giants of yesterday no longer even dwarfs. The current generation does at least two megawatts (MW), nearly 20 times more than Micon’s bestseller. The towers have grown to more than 100 meters, and the individual blades are longer than 50 meters several times since then. Past is the leader of the Enercon E-126 manufacturer Enercon, which is a 7.5 MW plant in the world as the most powerful and admired, among other things in Belgian wind farm is Estinnes. However, many of these wind turbines look more as a prototype for a fully developed product series – not least because there are only a few cranes, they can set up. The 131 meters high tower consists of 35 segments, the rotor diameter is 127 meters, and the nacelle behind the rotor hub weighs about 650 tons. Given these enormous dimensions of the giant plant takes a special place – on land, the average wind turbine size is for reasons of logistics currently between two and three MW.

It behaves differently in plants at sea: Here are five MW turbines has become a standard. And even that many operators still not enough, because the larger and more powerful than the plant, the higher the current efficiency and profit. Is for this reason, the trend towards offshore, rather few, but very big draw for 20-MW plants, because:

  • large systems save space. In comparison with four small wind turbines with the required intervals, the new class consumes less power for the same area.
  • The weather window, that brief period, can be built in the open sea and thus one of the most critical factors in the offshore installation will be better utilized. Instead of four units must only be set up and connected – this saves time.
  • The costs are divided better. After all attributable to the offshore wind turbine itself, only a third of total costs, say industry insiders. The majority would devour logistics and network connection. Only needs to set up a plant and therefore only one instead of several cables are laid, which is cheaper and less complicated.

Therefore scientists are working hard to develop a new generation of true wind giants. Within the European research project UpWind scientists have ventured a look into the future and explored what is technically feasible. Conclusion: giant wheels with rotors of more than 200 meters in diameter and up to 20-MW generators are realistic.

The way to the mammoth turbines, however, leads initially to smaller models – the giants today at 5 MW. Areva Wind, REpower and Bard have been collecting years of experience in this class. Their findings are incorporated into the development of the next stage of evolution. ‘The current 5-MW plant is an interim step,’ says Christian Nath, Germanischer Lloyd convinced. Therefore the wind farm are now developing systems that are intended for offshore use – large wind turbines that achieve high availability. The world market leader Vestas just promoted his 7-MW offshore turbine. 2-B Energy in the Netherlands is testing a model of its 6-MW turbine, as well as Nordex, and American Superconductor will stand strong with his ten MW ‘SeaTitan’ in the lake. Similarly, the Norwegians by Sway with its floating 10-MW plant.

These machines will be in addition to some other, the first true offshore developments. While many other companies promise high seas large-scale systems, but can show any concrete results. To schedule Clipper, Mitsubishi, Samsung and United Power also 10-MW machines for use at sea. But even these plants probably only an intermediate step will be.