These turbines are similar to waterwheels in that they are turned around by the water flowing through. In the case of turbines, the mechanical energy of their turning is used to generate electrical power that is sent along power lines to homes and factories. There are a few places in the world where there is a large enough difference between the high and low tides of the ocean to generate electricity. Water is collected behind a DAM at high tide, held for a few hours after the tide changes, and then released. As it surges down to the lower level, it turns turbines and generates electricity.
Ocean tides rise and full due to the gravity of the moon as it pulls upon earth's waters from space.
The first tidal power station began working in France in 1968. Some of the highest tides in the orld are in the Bay of Fundy in Nova Scotia , where a large tidal power station is being built.