A quick google finds a few sources on this.
"“Such a project has to be calculated very carefully,” he says, “and compared to other renewable energy sources regarding the cost per kilowatt hour.” "
But not to conventional energy sources?
Of course, this is fully to be trusted since it appears in that paragon of scientific authenticity, the New Scientist https://www.newscientist.com/article/dn18970-sailing-ships-could-harvest-fuel-from-the-oceans/
which says the idea originates with Max Platzer and Nesrin Sarigul-Klijn at the University of California.... (not Nether Wallop, but close?).
The Radio 4 program is "The Power of Wind" http://www.bbc.co.uk/programmes/b076nx1l (start in around 16 minutes)
Now maybe this is all perfectly feasible, perfectly valid but down the years I have become ever more cynical and ever less trusting of what scientists say. The proof ought to be in the pudding, in the eating, but......
....and however plausible the basic technology, the missing element is the cost benefit.
It helps when for "revenue" you can rely on subsidies.
I would guess that some of these schemes are really trying to source subsidies and grants. It beats making something that is cost competitive. On the other hand I wonder if all that ingenuity that goes into these various schemes might not be better employed pursuing better solutions.