It may surprise you, but I am disappointed in the whole area of green energy. It is more lipservie than reality.
I made windgenerators for a number of years, especially for sailboats, I made a 250 watt one, and 800 watt one. For a while the small one sold reasonably well, since I practically gave them away, then my supply of small generators dried up, and I had to purchase from a new source, and the price had to go up, then the sales dropped dramatically. End of wind generators, sailors did not buy them, unless they were dirt cheap.
Then I started making solar panels, and sold them for less that half the price of imported ones. I expected a land slide of business from boaters, did I get it. You guessed it - nope. Two years ago you could not get enough, today they can sit in my shop and will probable die there. Gave som away to friends.
Soooo, dont talk to me about Green Energy for boats. It is a nice dream.