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| Tidal power stations | |
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This type of power station can be used only under certain conditions: The height difference of the tides (difference sea levels between ebb and flood) must be large at least some meters, moreover a bay must exist, which is can be locked with a dam. With tide water arrives into the bay and propels the tubing turbines which are situated in the dam. If ebb prevails the water flows off and shifts the turbines in motion. These power stations can produce up to 240 megawatts electricity. Additionally they are very pollution free, as no water is derived and neither culture nor living country must yield such a power station. These power stations can also be operated as pumped storage power station. However many fish die in the turbines. Besides a tidal power station is very expensive and it produced also current, if they have not to. Besides the tides shift themselves daily approx. 50 minutes and do not follow the rhythm of required electric current. |
 Tidal power stationsLow pressure run force power stationPumped storagepower stationsStorage power station
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| Low pressure run force power station | |
| In contrast to the storage power station this power station operates with the water of the large rivers. The height of the run power station is very small, the flow of water nevertheless very high. Because of the small height (to 25m) Kaplan turbines are used. The advantage of this power station consists of the fact that it can always be in operation and thus the current production is always possible. If however the power station is stored the water flows unused over the resistance and if the river leads few water, the electricity production is only conditionally realizable. |
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| Pumped storage power station | |
| This power station is almost the same as the storage unit. If the requirement of current is not very high, for example at the night or on weekends, the generator is propelled with the surplus current. A pump is propelled by the generator, which pumps the water from a low-lying basin to a high-altitude (artificial lake). With this method energy is again stored and can be used at another point in time. Additionally they use the same generator for the generation of current as also for propelling the pump and the water is transported in the same lines from and to artificial lake. That will say that a pumped storage power station needs not very much more space than a storage power station. The supplied electricity can be recovered by only about 75%. Such a power station is however meaningful, as the surplus energy is not lost. |
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| Storage power station | |
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Of artificial lake arrives the water over penstocks and shafts at the power station. There it meets a turbine, which propels a generator. This machine produces current. Depending on the higher or lower downward gradient of the penstocks (few bent) and the shaft (more strongly bent), different turbines are used. The Pelton turbine can be used with large height and needs few water to be propelled. The Francis water turbine is until today the most used turbine. In former times it was used only in connection with flat downward gradient, but today it can master heights up to 700m. The Kaplan turbine resembles a marine propeller in its appearance and is actually not used in a storage power station. Separate only in run power stations with a max. height of 30m. The advantage of a storage power station is that it can be put into operation within minutes and if the power station does not work no water will flow away. |
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| The advantage of a storage power station is that it can be put into operation within minutes and if the power station does not work no water will flow away. |
Water energy generallyPower stationsDamsHistory |
| Power stations: Water energy: Power stations |
 
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