Hydrogen is theoretically a clean fuel. If you burn it, you produce only water.
You can get hydrogen from water with electrolysis, but this is expensive. 90% of all hydrogen right now is obtained from fossil fuels.
But this device gets hydrogen from seawater. The article mentions electrolysis, but there are not a lot of details as to how this works. It also mentions fresh water from seawater, something else that is sorely needed.
Take a look. If this is really a breakthough then it is a great one!