Offshore Wind Energy

Commercial-scale offshore wind facilities are currently in operation in shallow waters off the coasts of Europe, but further technology development is needed for use in the deeper waters of the Outer Continental Shelf (OCS).

	Wind Facility, Sweden. © GE Energy

Wind is air in motion. Since the earth’s surface is made of various land and water formations, it absorbs the sun’s radiation unevenly. Wind is produced by the uneven heating of the earth’s surface by the sun.

Onshore, wind energy has been utilized for power generation for more than two thousand years. In modern times, wind energy is mainly used to generate electricity, primarily through the use ofwind turbines. Wind flows over the airfoil-shaped blades of wind turbines, causing lift (similar to the lifting force on airplane wings), causing the turbine blades to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.

Offshore Wind Energy Resources

Offshore wind turbines are being used in a number of countries to harness the energy of the moving air over the oceans and convert it to electricity. Offshore winds tend to flow at higher speeds than onshore winds, thus allowing turbines to produce more electricity. Much of this potential energy is near major population (and energy load) centers where energy costs are high and land-based wind development opportunities are limited.

Because the potential energy produced from the wind is directly proportional to the cube of the wind speed, increased wind speeds of only a few miles per hour can produce a significantly larger amount of electricity. For instance, a turbine at a site with an average wind speed of 16 mph would produce 50% more electricity than at a site with the same turbine and average wind speeds of 14 mph.