Hawaii is a chain of seamount islands, so the deep ocean isn&#x27;t far away. That&#x27;s unusual.  Continents have a continental shelf, and it&#x27;s usually a longer pipe run to the deep ocean, which means the 4°C cold water warms up along the way, plus pumping costs are higher.<p>Solar works so well in Hawaii that the power company there is trying to stop it.  Once batteries get a little cheaper, Hawaii will be mostly solar.