For us it had nothing to do with being Green. It was all about self-sufficiency and comfort.
The first thing you need to do is quantify your electrical
needs/wants. This will depend on two things:
1. Lifestyle/comfort level: small refrigerator
? Big one? None? Watermaker
? Hot water shower
every day? computer?, etc.
2. The specific equipment
on the boat
you will be cruising - eg. Halogen lights will use more power than fluorescents and fluorescents will use more than LEDs and solar
garden lights use none at all. Until you have the boat
you want equipped the way you want, the best you can do is an estimate of average demand on the boat with the equipment
you think you will have.
Once you have a fair idea of what your demand will be, you can try to calculate what wind/solar equipment would be necessary to meet all or some of this demand and whether you can fit it on the boat you intend to use. How practical the result is depends in part on where and when you go. Becalmed in a fog
bank off the coast of Maine
, you either run down the batteries
, fire up the engine/generator, or go without power. OTOH, your refrigerator
will use less power on the Maine
coast than it will on the Venezuelan coast.
FWIW, our electrical
demands for our lifestyle were about 50 to 80 amps and we were fairly consistently able to meet them with solar
(360 watts solar panels
and KISS wind generator) in the Bahamas
and eastern Caribbean
where there is a lot of sun and wind.