There's still the issue of using our most precious resource up the way we do everything else. It could be done with desalination plants like they already use in California. There's also research into doing it more efficiently:
So, dealing with the fuel source using ocean is a possibility. (light bulb) Might even be a solution to rising oceans as arctic caps melt. Now there's some original thinking on the topic haha. Probably wouldn't work in reality but might make a good movie scenario.
