Space - The Only Frontier?

Anyway to all those climate change folks I need an answer to the following.

How many Km2 do you need for a wind farm to produce the power of (let's say) Fiddler's Ferry Power Station?

Only it appears to me, that if we were to move over to offshore wind power we'd need to shove an awful lot of concrete and steel into those oceans to the extent that the displacement may well raise the sea levels, just so that we can provide enough power to energise our solar panels in the winter.

Or have I missed my guess here?