Water takes a lot of energy to split. Take a small size as a pot on a cooker with a litre of water. Just to get that litre to bubble takes constant. Heating fo

Water takes a lot of energy to split. Take a small size as a pot on a cooker with a litre of water. Just to get that litre to bubble takes constant. Heating for minutes or imagine how long it would take to boil all that water away. Sure you'll have a lot of fuel but its not easily accessible.