Why cars can't run on water

Every consumer and environmentalist has long wished for cars that run on water. Petrol, diesel and CNG are all fossil fuels, a very limited resource. It takes millions of years for them to replenish. Moreover, very soon we are going to run out of this source of energy, scientists anticipate. So, wouldn’t it be nice if all motor-powered vehicles could run on a resource like water which is abundant and covers more than 70% of the Earth’s surface? Unfortunately, water-powered cars currently seem to be an impossible dream.  

Why water? 
A water molecule is comprised of two elements: Hydrogen and oxygen.  While oxygen is irrelevant to our problem, hydrogen is the fuel that can solve this dilemma. Hydrogen supply is limitless in the environment and burning hydrogen causes no harm to the Earth as it simply returns the gas to the form of water. When we burn hydrogen, it releases a tremendous amount of energy per mole. 

The chemistry doesn’t work in our favour 
Water cannot “burn” like fossil fuels. We must employ an electric motor that that converts hydrogen into energy. The power to move the vehicle actually comes from the burning of hydrogen, which is derived by electrically splitting water molecules into hydrogen and oxygen gases through electrolysis. The first barrier to this is the production of hydrogen by separating oxygen atoms from those of hydrogen in water. The laws of thermodynamics require that the energy inputs to create a fuel will always be greater than the energy we get back when using that fuel. So, breaking those bonds will always take more energy than we get back. The second problem is that hydrogen is dangerously flammable which gives even a minor accident the potential to become a gigantic explosion. 

Research and innovation 
Some researchers have designed cars that sit between water-powered cars and traditional gasoline-powered cars. They’ve discovered that an H2 (ionized hydrogen) and gasoline mix can increase fuel energy. This ionized hydrogen can also be used on its own to power cars, which is the case in water-powered cars that produce ionized hydrogen by processing it with pulsed electricity. However, the concerns are that continuing to process this ionized hydrogen can produce radioactive hydrogen gas. 

The future of water-powered cars remains uncertain. This is because, a revolutionary innovation in their design is required in order to make them truly clean and viable for proper commercialised use. Right now, there is no way to turn this dream into a feasible reality.