I like the concept, I don't like how vague the dude is about it. For starters water conducts electricity already and using salt water would increase that property at the cost of corroding the elements quicker.

A friend of mine has plans for a hydrogen fuel cell which he plans to play with on an old generator motor since they run at a constant speed negating the need to spend years getting the tune right. If it does work then it's awesome, if it doesn't hey it's just an old generator.

If people weren't hushed for trying to find a better fuel source we'd have had it decades ago