Tidal generator
Under the name Tidalgenerator was in Research Josef Becker a Horizontalachs- turbine developed with three flexible blades for extracting tidal energy and tested. Unlike previous tidal power plants , tidal generators do not need a dam or a location in estuaries .
history
The tidal generator for generating electricity from the tidal energy was one of the first developments by the Josef Becker Research Center, founded in 2010. After a theoretical investigation to estimate the various influences, the decision was made in favor of a 50 kW system. An optimum weight was found here. For comparison: 20 tidal generators of 50 kW each with a total output of 1,000 kW result in a total weight of around 16 tons. For large flow turbines with a nominal output of 1,000 kW , three manufacturers specify weights of 125 to 180 tons.
Working principle
The tidal generator is a fixed propeller with a diameter of 3.5 to 4.5 meters, which drives an asynchronous generator with a rated output of 50 kW via a planetary gear . A frequency converter converts the generated voltage with a frequency that depends on the flow velocity into the mains frequency of 50 Hz. The rotor blades are elastic and deform when the currents are too large or when the waves are influenced. The deformation changes the pitch angle and prevents a further increase in thrust, which is intended to prevent overload. To ensure that the flow is as undisturbed as possible, the turbines should be installed at the specified distance from the sea floor, as the current on the floor becomes increasingly slow. It is the same with the surface of the water. Here, too, the flow slows down. In addition, there are disturbances here from the waves.
prototype
The first prototype was tested in extensive tests in the laboratory. The second series of tests was carried out in the sea at the bow of the port tug Fairplay-26 with the advantage that the current speeds could be set reproducibly via the ship's speed. The tidal generator was mounted in a fold-up bracket so that changes to the experimental setup and controls of the measuring sensors could be carried out easily.
realization
Several tidal generators are attached to a platform equipped with ballast tanks that is only attached to the seabed at one point with a swivel joint. This enables it to align itself independently with the tidal current. The platforms are accessible for maintenance work on the systems when the ballast tanks are emptied. They then float up and are comparable to a catamaran. In this floated state, they are also taken to the installation site by tractor.
background
In contrast to wind, the currents of ebb and flow, which are precisely predictable, can generate climate-friendly energy in the form of electricity with this technology. They result from the gravitational pull of the moon, which orbits the earth. In extreme cases, it caused sea level fluctuations of up to 16 m in a few locations. In bays and straits there are fast currents that can be used in the future without harmful emissions.
See also
literature
Lange, Niels; Armstrong, John: Economic Use of Tidal Energy. Ship & Harbor No. 3/2013