In the case of the automobile propulsion, hydrogen can be used in two ways: the Fuel Cell or burning directly into the cylinders. The potential for hydrogen is huge, because it can eliminate the dependence on oil.
Hydrogen (H2) is the most easy and abundant element in the universe. The problem is that on Earth is not find in free form but in combination with carbon (C) and oxygen (O2). Thus, hydrogen can be obtained by electrolysis of water, which involves the dissolution of the oxygen and hydrogen bonds with the electric power, or by reforming of fossil fuels (typically natural gas).
An engine that burns hydrogen instead of gasoline, is more robust because the pressure resulting from the combustion is higher. A hydrogen engine has the power increased by approximately 20% compared to the same engine with conventional fuel. Once stored, usually in the gaseous or liquid, the hydrogen can be used as a fuel for internal combustion engines.
The use of hydrogen as fuel for internal combustion engines or fuel cells could be an alternative to fossil fuels. However major problems encountered by industry based on hydrogen are mainly :
- Hydrogen extraction with an efficient technology (yield around 90%) and highly flammable
- Storage medium at very high pressure (300 bar)
- Lack of fuel-delivery infrastructure
- High cost of the vehicles and high fueling cost
With a full hydrogen tank, these cars can have over 500 kilometers of autonomy, being completely silent and zero-emission. The only emission is water!
Fuel cell cars
Although still in its infancy, fuel cell cars, based on hydrogen, have the potential to revolutionize the automotive industry. Using fuel cells reduce automobile emissions to zero, the only products resulting from chemical reactions as electricity and water (H2O).
Fuel cell cars are still powered by electric motors. The difference with electric cars is the power source. In the case of hydrogen fuel cells, electricity is produced by a chemical process by combining hydrogen (H2) and oxygen (O2).
The Necessary Hydrogen for producing electric energy can be stored under pressure in the car, or may be produced, also on board the vehicle, with the aid of reformer using methanol, natural gas or gasoline. The disadvantage of the use of a reformer, instead of pure hydrogen, consists in the low yield, due to the introduction of a extra chemical reaction for the production of hydrogen.
Research has shown significant progress in the development of fuel cell and hydrogen burning directly into the internal combustion engine. However the costs of extraction, storage and distribution of hydrogen is still very high. This is why cars that use hydrogen as fuel are mostly in prototypes stage and in the near future will not be considered a real alternatives to those that use fossil fuels.