Theoretical study was conducted to investigate the distinction between cracking systems process technologies. The purpose is to feed pure hydrogen gas to the fuel cell as the renewable energy power source. Three types fuels of Hydrocarbon were involved namely gasoline, iso-octane and diesel. Theoretical calculations and synthesis gases of hydrogen, carbon dioxide and carbon monoxide were carried on. Steam reforming process of gasoline achieved a conversion of 68%, 75% for iso-octane and 55% for diesel. Auto thermal reforming produced 55% of H2 for gasoline via 35% for iso-octane and diesel. The process of dry reforming produced 50% of H2 for gasoline and 35% for iso-octane and diesel. The amounts of CO2 were analyzed for the cracking processes of the same gases. CO2 generated in steam reforming was 40, 35 for iso-octane and 25% for diesel. Auto thermal reforming amount was 25% of CO2 for gasoline and 28% for iso-octane and 40% for diesel. Dry reforming process reached an amount of gas of 35% of gas for steam reforming process of gasoline and 30 for iso-octane and 25% for diesel. Generation of CO gas for gasoline, iso-octane and diesel were also performed. Steam reforming processes contain 30%, 30%, 35%; respectively. Auto thermal cracking produces 30%, 30%, 45% of CO; respectively and in comparison with 35%, 25%, 44% of CO from dry reforming type processes. Data regarding cracking reforming chemical process [1, 2] were evaluated and recognized some disagreement.