For years, technological visionaries have painted a seductive vision of using ocean tides and waves to produce power. They foresee large installations off the coast and in tidal estuaries that could provide as much as 10 percent of the nation’s electricity.
But the technical difficulties of making such systems work are proving formidable. Last year, a wave-power machine sank off the Oregon coast. Blades have broken off experimental tidal turbines in New York’s turbulent East River. Problems with offshore moorings have slowed the deployment of snakelike generating machines in the ocean off Portugal.
Years of such problems have discouraged ocean-power visionaries, but have not stopped them. Lately, spurred by rising costs for electricity and for the coal and other fossil fuels used to produce it, they are making a new push to overcome the barriers blocking this type of renewable energy.
The Scottish company Pelamis Wave Power plans to turn on a small wave-energy farm — the world’s first — off the coast of Portugal by year’s end, after fixing the broken moorings. Finavera Renewables, a Canadian company that recently salvaged its sunken, $2.5 million Oregon wave-power machine, has signed an agreement with Pacific Gas & Electric to produce power off the California coast by 2012. And in the East River, just off Manhattan, two newly placed turbines with tougher blades and rotors are feeding electricity into a grocery store and parking garage on Roosevelt Island.
“It’s frustrating sometimes as an ocean energy company to say, yeah, your device sank,” said Jason Bak, chief executive of Finavera. “But that is technology development.”

Power From the Restless Sea Stirs the Imagination – NYTimes.com






















