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Marine Renewable Energy

Where Does Tidal Energy Come From?

The gravitational force of the Earth stops the ocean from floating off into space, just like everything else. The Moon also has a very weak gravitational effect on the Earth, which is not normally noticable as far as falling teacups are concerned, but the ocean, which can flow around the globe to even out differences, is noticably affected.

The Moon's influence is strongest on the side of the Earth facing it and weakest at the Earth's far side. Ths causes the ocean to sit in a slight 'bulge' shape facing the Moon, which results in water levels rising and falling twice in a day as the Earth moves through this bulge (see diagram). The Sun also creates a smaller bulge, which results in smaller or larger tides throughout the year depending on when the gravity of the Sun and Moon act in the same direction or against each over.