Man has been using wind energy for thousands of years: as a means of propulsion for sailing ships, and for performing mechanical work using windmills. Since electricity was first discovered, wind energy has also been used for electricity production.
Thanks to the advancement of fluid mechanics, rotor designs and superstructures have become increasingly specialized. Today, wind energy is an advanced technology featuring ever taller, larger and higher-powered wind turbines. In line with these developments, the installed wind power capacity worldwide is growing constantly.
The principle of wind energy production is very simple: the rotor turns with the wind and drives the generator in the nacelle. This generator converts the mechanical rotational energy into electricity which is then fed through cabling, via the transformer, into the grid.
Even when the rotor appears to be turning very slowly, the tips of the rotor blades are moving at a speed up to 300 km/h, depending on the rotor diameter. The rotors are designed for specific wind conditions; for instance, in strong gale conditions they are stopped by a braking system and turned out of the wind to prevent damage.
Wind farms can be built onshore and offshore. The advantages of onshore installations are: many years of experience, mature technology, installation designs optimized to cope with local conditions, and lower investment costs which have a positive knock-on effect on investment risks. Disadvantages compared to offshore installations are: lower energy yields and greater fluctuations in power production.
As mentioned earlier, offshore installations benefit from favourable wind conditions that enable significantly greater energy yields and more consistent energy production due to unimpeded plant operation. However, construction and operation are more expensive and have more attendant risks: the costs for foundations, grid connection and maintenance are all high – under certain sea conditions with a heavy swell, plant access is no longer possible. Seawater also presents a more corrosive environment for materials, and counteracting the effects also requires further investment.
Compared to countries with windswept coastal regions, Switzerland cannot be classed as a typical country for wind energy production. However, the Jura and other mountainous regions provide suitable locations, and BKW is pursuing various projects in these areas. On account of the more favourable wind conditions, however, BKW is investing in wind technology primarily in its neighbouring countries Germany and Italy.