Some artificial islands seem necessary. Some just are and some are excessive. And some may sustain human life in the future. Yesterday LiveScience reminded us of a promising idea that we covered earlier: creating rig-like islands that drill the oceans not for oil but for renewable energy.
At the core of each man-made island -- the brainchild of inventor Dominic Michaelis and his son and architect Alex -- are power plants that rely on ocean thermal energy conversion (OTEC). That is, they use the differences in temperatures at the depths and surface of the ocean to evaporate and condense another fluid substance, like seawater, which in turn pushes a turbine. The resulting power, they say, would be 250 megawatts (MW) -- enough to drive a small city.
But the OTEC process itself -- one that's been around for over a century -- requires pumping up large amounts of cold water from the depths of the ocean -- more than 100,000 gallons (400 cubic meters) of cold water per second to be exact. To do it, the 2,000-foot-wide (600-meter-wide) energy island would draw energy from additionalwindmills, solar collectors, wave energy converters and sea current turbines. As if that weren't enough, if seawater is used to push the turbine, it would be desalinated in the process, yielding 300,000 gallons of fresh water per megawatt of electricity produced every day.
