Two basin schemes have the advantages over normal schemes is that generation time can be adjusted with high flexibility and it is also possible to generate almost continuously. Consequently the level of water in basin A starts rising. When its level becomes equal to low level of the upper basin, the inlet gates are opened. ![]() When the tide reaches its lower most level, the outlet gates are closed. When the rising level in lower basin B becomes equal to the level of the falling tide, the outlet sluices are opened. Thus, the water level in the upper basin falls and that in the lower basin rises. The water flows from the upper basin to the lower basin through the turbines. When the tide attains its peak value, the water level in basin A is maximum the inlet sluices are then closed. The power generation thus continues simultaneously along with filling up of water in basin A. The water flows from basin A to basin B through the turbines and the power is generated. When the water level in upper basin A provides a sufficient difference of head between the two basins, the turbines are started. The high level basin gates are called the inlet gates and low level gates as outlet gates. One basin is called the upper basin the water level is maintained above that in the other, the low basin. The sluice gates are provided in the dam. ![]() There are two basins at different levels. Electric power is generated during two short periods, during each tidal period of 12 hours 25 minutes or once every 6 hours and 12.5 minutes. In this system also continuous generation of power is not possible because of short duration. The flow of water in both directions is used to drive the reversible turbines. Filling process occurs when the ocean is at high tide while the water in basin at low tide level, the emptying occurs when the ocean is at low tide and basin at high tide level. In double cycle system, the reversible turbines are installed and power is generated during filling and emptying of basin. In this system also the power output is intermittent. The basin is drained into the sea through the sluice ways. As the flood tide period is over and the sea level begins falling again, the generation is stopped. The sea water is admitted into the basin over the turbines. In single tide cycle system, the generation is affected when the sea is at flood tide. The power output from such system is intermittent in nature and highly variable. The turbines are designed for single way operation. ![]() The generation of power takes place, when the water from the basin flows over the turbine into the low level sea water. Tidal range provides water head during low tides. The energy is stored in the form of tidal range. The level of the basin begins increasing. In single ebb-cycle system, when the high tides (flood side) are falling, sluices are opened to permit the sea water to enter the basin, while the turbine sets are shut.
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