I wonder if the power budget in Hawaii would permit the other kind of air conditioning, where you soak down a large water thermal mass, and then use it to do the chiller side. I know nothing is free, but its a model which quite a lot of places are moving to, in search of a different pattern of energy usage. Hawaii might be one of the hard cases: I believe it has really high, and until recently diesel backed power and this kind of off-peak power may simply not exist.

It's a complementary technology to this use of powerwall. it's not an either-or thing.