COURTESY : www.sustainablemarine.com
Green tidal energy
In fact, it lays claim to being the most predictable form of renewable energy in existence. Scientists are actually able to plot tidal movements hundreds of years in advance, since it is directly influenced by well-known cycles of the moon, sun and earth, and remains unaffected by weather conditions.
Tidal Energy is increasingly being recognised as a highly valuable marine energy resource, while helping protect coastlines and waterways vital to the culture and economy of remote, coastal communities.
Tides are created by the gravitational pull of the sun, moon and the rotation of the earth, with tidal bulges developing due to the Moon’s gravitational pull. These tidal bulges move as the Earth rotates and the Moon changes position relative to the Earth.
The part of the Earth closer to the Moon is more strongly attracted than the part farther away, creating an elongation in both directions. Since the Earth rotates a full turn every day, the point on the Earth that is being pulled toward the moon is constantly changing, altering the position of the tidal bulges.
Due to the earth’s continents the even flow of water is disrupted and displaced, and a complex pattern emerges. In some locations, the water stretches out more towards the Moon. In other places, tidal nodes occur where the water does not really deform at all.
Strong tidal resources are often found in narrow passages. As coastlines approach each other, or as the seafloor shallows, the water is ‘pinched’ which increases water speed – like pressing a thumb on to a garden hose. Power goes up exponentially with speed and every time water speeds doubles, power increases eight-fold.
