RE: solar power. Unless you are VERY qualified, have lots of money and are willing to make a major lifestyle change, forget solar. Solar energy has to be stored in batteries. Large projects require large (expensive) batteries that have limited lives. Where do you suppose the folks at Long Caye will dispose of these large, nasty batteries? Oh, they'll tell you solar is coming, while running their generators. You know, the ones that need oil changes (where does the spent oil go). Did you notice how close they are to one of the most pristine dive locations in the world? No, they won't be another San Pedro, they'll trash it first.
Solar energy is very inefficient. It has to be stored as DC (direct current)then inverted to AC (alternating current) so you can use it in your everyday appliances and loses 15-20% in the inversion process. Forget a fridge, too much usage. Same for washing machine, air conditioner or anything else with a large AC motor or compressor (do dive shops and recompression chambers sound like they fall in this category?).
Every community in Belize that has used solar has switched to grid electricity at the first opportunity. Does that tell you something? Any expectations of getting grid electricity to Long Caye?
Solar (and wind) sounds nice, but it is not for most people and won't be for a long time. In theory it's great: every second, enough energy falls on the earth's surface in the form of solar power to supply the world's electrical needs for a year.
Sorry to sound negative, just relaying the reality of it.