How can people get all the hydrogen that needed even if it become widely accepted
The earth is covered with water. water has two hydrogen atoms covalently bonded to a single oxygen atom. Expect price to go down after technology gets adopted.
yes it is very practical , in the same way you can transport other fuels , like gasoline , but the carbon foodprint is much less then with normal fuel , so it is a good idea , right now they are not very good but they will become better when the market for fuel cells is getting bigger
