And alternatives to an engine! When it comes to sailing the only correct perspective on that is no engine, no electrical needs, and no noise......or so I've been told.
But I agree wtih mitempo. All he has to do is look past the "I'm right" which is in these posts by their nature to see that engines are good, can be used to charge batteries, generators are nice and quieter than engines and cheaper than wind and solar.
If I had the money I would go with a fuel cell. I think the The EFOY 900 fuel cell would be all I would need for my electrical needs.
But the EU2000i is much cheaper and much less noisy than the engine so it wins hands down as the other charging method.