Seite - 144 - in Water, Energy, and Environment - A Primer

(52), ‘Anaverage4-foot,10-secondwavestrikingacoastputsout morethan35,000horsepowerpermileofcoast.’Anotherestimate (Wikipedia, ‘Wave power’) is that ‘Inmajor storms, the largest waves offshore are about 15meters high and have a period of about 15 seconds, such waves carry about 1.7 MW of power across each meter of wavefront.’ The global potential is estimated to bemore than 2 TW.Areaswith themost potential include the Pacific coastlines of Australia, New Zealand, Southern Africa, and North and South America. Other promising areas are the western coasts of Europe and the northern coast of theUK. Wave energy offers several advantages over other renewable energy technologies: it is produced 24/7, is more steady in output andmore predictable thanwind or solar, can be located close to large coastal population centers with large energy demand, generally has lower infrastructure costs, and is less obtrusive visually than offshore or land-based wind turbines. It still requires cabling to deliver power to shore, incurs all the difficulties of operating reliably in an ocean environment, and can be disruptive to ocean life and thoroughfares for coastal vessels of all types. Theworld’sfirstcommercialwaveenergydevicewasinstalled off thecoastofScotland in2000,and the first experimentalwave energy farm (three units) in 2008byPortugal. Today,Australia, the UK, and the US have experimental wave energy farms inoperation. 8.7.2 Oceancurrentenergy Asecond ocean energy technology under development is ocean (marine) current power, which began to draw attention after the 1973–74 Oil Embargo. As with wave power useful energy is derived from the kinetic energy found in the oceans, but in this case it is derived from ocean currents flowing beneath the ocean’s surface (53). An example is the Gulf Stream that Water,Energy, andEnvironment–APrimer144