Take a huge oceanic catamaran, stick a hydroelectric turbine underneath it, and hitch it to a 6.5 million-square-foot parafoil flying nearly a mile in the air. That's a Korean research team's new proposal for generating gigawatts of clean energy.

As the parafoil pulls the boat, seawater would be forced through the turbine, which generates electricity. The 800 megawatts of electricity produced would separate seawater into hydrogen and oxygen by electrolysis, and the hydrogen would then be stored on-board the ships.

"The calculation shows that, with a large such ship, a gigawatt order electrical power may be harvested by this system," wrote Park Chul of the Korea Aerospace Research Institute and Kim Jongchul of the Korea Advanced Institute of Science and Technology, in the journal Energy in March.

"If such ships are deployed at 20-km (12.4-mile) intervals over two temperate zones, one in the middle of the Pacific Ocean in the Northern Hemisphere and the other everywhere in the Southern Hemisphere, the total power produced will be many times that needed by the world," they wrote.

The new system is a remarkable, if a bit wacky, synthesis of different lines of new energy R&D. Park and Kim rightly note that parafoils – large industrial-strength kites – are now used by the German company Skysails to reduce the fuel consumption of ocean-going vessels by up to 35 percent.

High-altitude wind power using similar parafoils has received increasing attention from entrepreneurs and green tech backers like Google.org because the higher you go, the better and steadier the winds are.

And small groups have been working on hydroelectric generators mounted to sailboats.

But it's fair to say that though the system is largely a recombination of things that are on the cusp of feasibility, nothing even remotely similar has been tried, or even suggested, by anyone. As such, the components such a plant would need are not currently manufactured. For example, the largest commercially available parafoil has an area of just 6,835 square feet, or about 945 times smaller than the wing the researchers propose.

The idea doesn't even have a catchy name yet. Perhaps it could be called the "hydro paraplant."

"Wind power generation with a parawing on ships, a proposal" in Energy 35 (2010) 1425–1432 by J. Kim and C. Park

Images: 1. Skysails. 2-4. Kim and Park.

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