2,000 terawatt-hours (TWh) annually, could amount to nearly 16 percent of the world's current total

http://www.thefreelibrary.com/Oceans+of+electricity:+new+technologies+convert+the+motion+of+waves...-a0104682066

Waves are ultimately a form of solar energy solar energy. The sun heats up Earth's surface, causing winds that, in turn, drive waves. The best wave-energy regions tend to be on seacoasts at the receiving end of waves driven by the wind across long fetches of water. As the waves travel--say across the North Atlantic to the west coasts of Europe--the winds continually pump energy into them. By the time the waves hit the coast, they're brimming with power.

Wave-energy specialists have estimated the power content of waves off coasts all over the world. They rank the areas in terms of their waves' average rate of energy production, or power, in kilowatts per meter (kW/m) of shoreline. The ratings of the most power-rich areas, such as the west coasts of Scotland, northern Canada, the U.S. northwest and northeast seaboards, southern Africa, and Australia, range from about 40 to 70 kW/m. A typical American home, without electric heat, draws around 1 kilowatt on average and 3 to 4 kW during peak summertime use, says Steve Rosenstock of the Edison Electric Institute. in Washington, D.C.

Wave-power-poor areas include the coasts of the southeastern United States, northeastern South America, and southern Japan, where waves deliver only 10 to 20 kW/m. Power ratings vary seasonally. The most potent winds and waves appear in winter, when greater atmospheric temperature differences--and therefore greater atmospheric pressure differences--give rise to stronger winds.

Although variable from place to place and season to season, ocean waves stack up globally as a vast energy re serve. Renewable-energy-markets analyst Thomas W. Thorpe of AEA Technology in Harwell, England, has calculated wave power's potential worldwide contribution. If the technologies being developed today become widely used, wave energy could amount to nearly 16 percent of the world's current total electricity output, says Thorpe.