Oil needs finding, drilling, pumping, shipping, refining and shipping again all with significant infrastructure and often, war, before it can be used, and you're telling me that a wind turbine and cable is 'inefficient'. Ok.
I'm not annoyed, I think it's pointless to suggest extreme what ifs.
Yes, ANY defence destroyed exposes vulnerability but you are arguing a capability that isn't realistically possible bar China or the USA deciding to attack one of our vessels, and spending a lot on doing so. Realistically...