Renewable "Energy Islands" at Sea To Power Cities, Produce Fresh Water and More
Courtesy Energy Island
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 additional windmills, 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.
The How -- and How Much
To bring the energy to shore, the Energy Island would require underwater cables, or it could produce hydrogen that could be shipped to the mainland to be used in fuel cells.
According to the Michaelises, the exported electricity might cost 9 to 13 cents per kilowatt-hour, depending on financing. Today, energy produced by a modern wind turbine (at about 50 percent efficiency) costs about 8 cents per kilowatt-hour, while coal costs about 4. A single one of these energy islands has an estimated price tag of $600 million, say the Energy Island team. Though seeking $25 million from Richard Branson's Virgin Earth Challenge, the group was in Shanghai this week looking for investors.
The Times of London also reports this week that another energy island -- although one utilizing a hydroelectric system and costing €3-3.5 billion -- is being planned by Dutch company Kema for the North Sea. The 1,500MW project would provide supplemental power to the Netherlands wind portfolio starting in 2020.
Vacation Hot Spot?
Already, the father-son designers envision a colony of workers, complete with vegetable farms and homes.
But string a few of these islands together and you have an archipelago of energy platforms that could also serve as larger greenhouses for food, a harbor for ships, and a singular eco-resort for tourists. Just imagine: vacationing on a power plant, one that features not only swimming and water sports but -- thanks to all that deep ocean water -- some pretty lively fish and awesome aquaculture.
There's Always a But
Compelling as a sustainable, OTEC-solar-wind-energy-and-drinking-water-producing-island may be, especially given the resistance renewable projects suffer on land, it's important to ask what sort of impact these islands would have on oceans that are already being altered by human-induced climate change.
And it's still unclear if investing in this technology now -- and the infrastructure needed to connect it to the countries that need it -- trumps the solutions for renewable energy that are still being developed (or blocked) on land.
But there's nothing wrong with experimenting -- and the greater our energy and climate challenge becomes, the more we're going to be looking for ideas like this one.
And a not insignificant benefit: the energy island floats, meaning it can survive rising sea levels.
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Sea Solar Power, or Ocean Thermal Energy if you prefer