What is the buoyancy principle

Wind energy

The use of wind energy takes place in wind power plants. Modern systems use part of the wind's kinetic energy and slow it down in the process. The physicist Albert Bretz recognized in 1920 that the maximum power can be drawn from the wind when the wind is slowed down to a third of its original speed. The performance coefficient of a wind turbine describes this exploitation. Modern systems create a performance coefficient of over 50%.

A large supply of wind energy can be found on the seas, where no resistance such as forests or cities slow down the wind. Here one speaks of “off-shore” wind power plants. In order to find conditions similar to those on the open sea, ie high and constant wind speeds (25 to 30 m / s) with as many full load hours as possible (3000h / a), the "on-shore" wind turbines must be built taller and larger. Furthermore, the offer is very different locally. While in Germany the potential of wind energy can cover around a third of the demand for electricity, in Great Britain the demand can be covered and large amounts of wind power can be exported.

Wind turbines work according to the drag or buoyancy principle. With the buoyancy principle, greater power can be derived from the wind. The wind hits one of the rotor blades of a wind turbine and splits up. There is a pressure difference between the top and bottom of a blade, as the wind deposits different distances over the rotor blade. This pressure difference causes a lift force acting perpendicular to the wind, which causes the rotor blade to rotate.

Similar to the use of photovoltaics, a wind turbine can serve as an island system or as a grid-connected system. Grid-connected wind turbines have gained enormously in importance in recent years. Wind farms consist of at least three wind turbines. Offshore wind farms are wind turbines that are built on the open sea. Here the water depths and the distance to the coast do not have to be too great for offshore wind farms to be economical. Furthermore, the components of a wind turbine in the sea are exposed to greater weather conditions, so that the material resistance is of great importance. The installation of a wind turbine on the open sea is far more complex and very dependent on the weather conditions.