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Offshore Wind Resources Could Meet 25% Of US Demand
(cleantechnica.com)
This is a most excellent place for technology news and articles.
Salt water is a bitch. It will corrode though everything, especially moving parts. It's not that we couldn't do it, but the maintenance cost makes it unattractive.
Make it all out of whatever offshore windmills are made of (ok I say this half jokingly because I honestly have no knowledge in this area)