Regarding this, can we use water as fuel?
The cheat answer is yes, you can use water as a fuel. Water is made up of hydrogen and oxygen and the 'hydrogen' part is the one we are currently interested in. Because it takes more energy to make hydrogen that way than we can take energy out by burning it.
Also Know, why can't cars run on water? Using water to power cars is, unfortunately, only a pipe dream. Here's the problem, Cheng says: “A water molecule is very stable.” The energy needed to separate the atoms is greater than what you get back — this process actually soaks up energy instead of giving it out.
Similarly one may ask, can cars run on water instead of fuel?
Yes, you can run your car on water. The key is to take electricity from the car's electrical system to electrolyze water into a gaseous mixture of hydrogen and oxygen, often referred to as Brown's Gas or HHO or oxyhydrogen.
What would happen if vehicles run by water?
Yes it is possible but it will not fulfill your requirements like more speed, able to carry loads. It will produce very low power. And also water cannot be use as direct fuel in your internal combustion engine.
