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21 Ağustos 2007 Salı

Wave and Tidal Energy Rise


Energy You Can't Export

Your perception of the new world of energy is flawed. If you're like most of the public, you've swallowed the Kool-Aid that the existing energy regime is giving you. Namely, that ethanol, coal-to-liquids, and liquefied natural gas will save you. Wrong!


Our best hopes for energy independence (or more properly put, a "local energy base") aren't power supplies that can be loaded into tanker trucks or onto barges. Off the northern coast of Scotland, the turbulent waters of the North Sea deliver their best energy yields not when man-made devices move them, but rather when they move man-made devices.


In the Orkney Islands, a company called Ocean Power Delivery knows how to cultivate the rage of the seas with its wave-energy converter Pelamis. The company has received a four million pound grant from the Scottish Executive in Edinburgh, which decides Scottish policy initiatives separately from London's UK government.


But despite Pelamis's three-megawatt test site in Great Britain's chilly far north, the machine's first major generating capacity will be delivered off the western coast of the Iberian Peninsula, far south in Portugal. OPD says its Pelamis-powered wave farms link several generators in what is called a "sea-snake" array, each with about the same capacity as wind-powered turbines. A 30-megawatt installation can power 20,000 homes from just one square kilometer of ocean space.


From offshore, power can flow directly through a grid to cities like Edinburgh or Lisbon.
But even with the UK's high renewable energy targets (20% of total supply by 2020, and Scotland's own goal of 40%), the first step in the order of energy operations is conservation. That's one area where the UK needs a major nudge. The UK's Energy Savings Trust said in a report last year that in the three decades between 1972 and 2002, energy consumption from household appliances like dishwashers, blenders and hair dryers has doubled. The report, titled "The Rise of the Machines," forecasts a further 100% rise by 2010, sandwiching a few decades' intensity into less than ten years.


This is something that should worry Britons a great deal, especially with Europe's growing dependence on Russian natural gas. Instead of importing from Siberia, the UK is in a position to maximize its own native resources, and idle goals will not be enough.


Here in the States, where soundbites are often more valued than sound advice, wave power is only a small ripple in of a surge in public awareness of alternative energy.


Private utilities will be required to generate 15% of the electricity they produce from renewable energy sources by 2020, the same as the British target year, yet significantly lower than the British target percentage.


Some of that energy should come from wave power, and itsy-bitsy steps are being taken on our shores to get such projects afloat. The Federal Energy Regulatory Commission has several applications on file for projects such as the Portuguese Pelamis farm (which is still incomplete, though construction of the 2.25 MW system began in late 2006).


Oregon congresswoman Darlene Hooley sponsored a bill to inject $250 million into wave energy research and development, which was included in the House of Representatives energy bill that stipulates the "15 by 20" requirement mentioned above.


Verdant Power, an American start-up company, has placed prototype turbines in the East River in New York. That project will have to balance the desire for shorter cables to run power to shore with the reality of lower energy density (how power-packed the waves are) closer to shore and in inlets like the East River.


Roger Bedard of the Electric Power Research Institute estimates that 4.3 million homes could be powered by ten gigawatts of wave power and three gigawatts of tidal power (generated closer to shore).


Wave power may also provide a good alternative to wind power in places like Massachusetts, where the Cape Wind project has been held up by NIMBY (not-in-my-backyard) types. Though visually unintrusive, wave energy farms are criticized by some fisherman, who dread dragging up a turbine instead of a tuna with an errant net. But these are the challenges faced by every new invention, no matter how much good it does in the long run.


And it's clear that a rising tide of energy options has the potential to lift all the ships at sea in today's energy economy.

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