Thank you for your wealth of comments, sharing different perspectives! 
From all comments I take away that a wind generator definitely needs more than 10 knots of apparent wind to generate energy and that with regards to noise, it's about how I take it, but in an anchorage other sailors might have their own opinions about it ... It's interesting to see that if you had/ have a wind generator at all, you also have solar panels! 
@Dick I did not know of the AAC website and shall explore it now. 
@rhudson Richard, thank you very much for providing such a level of detail with regards to your experience - this is very helpful. 
@Nimue Anne & Michael, great to read that you tested all different types of energy generation and also mention the Watt&Sea hydro generator. Thanks for the offer to chat - I will send an email.