5. Offshore Wind

5.2. Energy Source and Location

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Wind is the movement of air; this carries kinetic energy which can be harnessed by wind turbines. The atmospheric winds that circle the earth are created because the Earth’s surface is unevenly heated by the sun, with the poles receiving less solar energy than the equator, and by the rotation of the planet. Warm air is less dense and lighter than cold air.  Air in the warmer regions rises, and cooler more dense air flows in to take its place, creating winds.

Because land and water absorb the sun’s heat at different rates, the air over land heats up and cools down more quickly than air over water. During the day, the air over land expands and rises and is replaced by the cooler sea air, creating sea breezes on coastlines. At night, these winds are reversed.

The greater the wind speed, the greater the energy it contains. Offshore wind speeds are generally higher than on land. As wind blows over the water surface generating waves, it loses some energy due to friction.

The energy in wind is stronger further from the coastline, and increases in strength with increasing height above the water surface.

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