Check out the videos, amazing infrastructure required.
Expensive at the moment, but predicting significant cost reductions on future projects.
https://arstechnica.com/science/2017/10/first-floating-wind-farm-built-by-offshore-oil-company-delivers-electricity/
First floating wind farm, built by offshore oil company, delivers electricity
The world’s first floating offshore wind farm began delivering electricity to the Scottish grid today. The 30MW installation, situated 25km (15.5mi) from Peterhead in Aberdeenshire, Scotland, will demonstrate that offshore wind energy can be harvested in deep waters, miles away from land, where installing giant turbines was once impractical or impossible.
