As much as I would prefer not to have a microwave on board, there are good reasons to have one if you cook a lot, even under way. Microwaves are extremely efficient using far less energy to heat something than carbon fueled
stoves and in warm climates they put far less heat into the cabin.
In theory, even without solar collectors or wind generators, the amount of
fuel needed to recharge the batteries is supposed to be less than the amount of
fuel used to heat food on a
stove or in an
oven.
On land I frequently use a microwave for cooking for health reasons. Microwaves keep more of the taste, destroy fewer vitamins and produce fewer free radicals than conventional cooking.
Jeff