Alternative propulsion system of a vehicle refers to the powering of the vehicle engine that run on fuel other than traditional petroleum fuels. Hybrid vehicles are not actually alternative propelled but its efficiency ca be bettered by implementing electric battery and a motor. The requirement of the alternative propulsion raised due to the evolving in the government regulations for environmental concerns, customer demand in the efficiency and due to the lack in the availability of the fuel. Talking about the fuel cells, hydrogen car is the one which utilises hydrogen as it source for the locomotive power. They usually use hydrogen in either one of the following : Fuel-cell or combustion process. As the combustion in the gasoline engines hydrogen is burned. Meanwhile in the fuel cell conversion, electricity is produced through fuel cells resulting in powering the electric motors. The vehicles currently running in gasoline can be converted into gaseous hydrogen. The most efficient way is to use the electric motors and the fuel cell rather than the traditional engines. Electricity is produced by the reaction process between hydrogen and oxygen inside the fuel cells which powers the motors.

The well-to-wheel analysis analysed for each pathway Using the GREET ( Green house gases, regulated emissions & energy in transportation ). They mainly contain distribution storage , transportation, production of fuel. The energy utilisation includes booth direct and indirect raw materials .

Cell design : Every fuel is made of three segments, mainly anode, cathode and electrolyte. In these segments two kind of reactions taks place. The product of both the reactions are water, carbon dioxide and electric current which is considered as load used for powering the mtotors.

2H2 + 2O2− → 2H2O + 4e (at anode end) O2 + 4e– → 2O2− (at cathode end) 2H2 + O2 → 2H2O

Fuel cell important design considerations are : •Type of the electrolyte used. •Type of fuel that is used. •Fuel is breakdown into electrons and ions at he anode caalyst. Anode is usualy platinum fine powder. •Nickel is the most coomonly used acthode caalyst.

Advantages :

•Emits only water vapour.

•Can store upto 3times while compared to conventional natural

gas.

•Cheaper than the gasoline.

•Engine have better strength an d durability.

•Engines can work in higher temperatures as well.

•Corrosion chances are less as compared to traditional engines.

Disadvantages

•Leakage in hydrogen which harmfully effects stratosphere.

•Production currently depend upon natural gas and electrolysis.

•Storage not easier.

CO2 considerations:

• The gratest advantage of the hydogen fuel cell is that it is non- polluting.

• Fuel cells only emit heat and water.

Well to wheel : is the assessment of life cycle of the fuels for automotive. These are usually divided into two sections mainly Well-to-tank and tank-to-wheel. One of the greatest advantage of hydrogen is it can be from nay primary energy source. Most of the Production is done by steam reforming NG. While compared to the petroleum well-to-wheel analysis, Hydrogen well-to-well Is 20% efficient.