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Friday, March 3, 2017

Cool ways to generate electricity from the ocean!

Ocean energy has many forms, encompassing tides, surface waves, ocean circulation, salinity and thermal gradients.  There is growing interest around the world in the utilization of wave energy and marine currents (tidal stream) for the generation of electrical power. Marine currents are predictable and could be utilized without the need for barrages and the impounding of water, whilst wave energy is inherently less predictable, being a consequence of wind energy. The conversion of these resources into sustainable electrical power offers immense opportunities to nations endowed with such resources and this work is partially aimed at addressing such prospects.
Researchers first examined how human-modified sea floors could mimic the ability of muddy shoreline seabeds to dampen and absorb ocean wave energy.  Then began considering how a synthetic seabed might harness that wave power to produce electricity, and this research led Lehmann to eventually develop the Wave Carpet.
A flexible membrane that runs the length of each Wave Carpet undulates in response to passing waves, absorbing much of their energy, just as muddy sea floors do.
Fastened to the membrane are a series of vertical double-action pumps. When flexed by wave energy, the membrane drives the pumps to pressurize and push seawater through a shared discharge pipe. The water gushing through that pipe powers a shore-based turbine that can generate electricity, drive a desalination plant, or do both.
The Wave Carpet is also designed to survive tough ocean conditions. It’s built of corrosion-resistant materials, operates submerged and thus sheltered from storm conditions, and sits far enough below the waterline to eliminate most surface collision danger.
An average device will measure about 30 feet long by 30 feet wide and about 3-10 feet high, depending on local conditions, says Alam. Several devices can also be sited together on one shoreline to power one or more turbines.