Hydrogen Transportation and Refueling

For automobile applications, H2 must be in either liquid or highly pressurized form. Due to the additional cost of liquefaction or pressurization, H2 costs for automobile applications may be about 20% higher than that for stationary use. Refueling of a car or a bus at an H2 station can be done in 3-10 minutes because the H2 supplied by the station is already in either liquid or highly pressurized form. 

Refueling stands displayed during the 2011 Tokyo Fuel Cell Expo. 

H2 is the lightest gas and it can rise at a rate of around 20 m s. Unless in a completely gas-tight environment, it is unlikely that H2 will accumulate in the environment, making it relatively safer than most of the common gaseous and liquid fuels. When H2 combusts or explodes, the process finishes instantly, making rescue efforts easier. 

Although H2 does not exist naturally on earth, it can be generated by a variety of methods such as electrolysis of water, thermal splitting of water, reforming of hydrocarbons, cracking of ammonia, reaction of certain chemicals with water, and biological processes using enzymes and bacteria. 

H2 is most commonly supplied in steel cylinders at a pressure of less than 150 bars. For vehicle applications, high-strength, lightweight cylinders with H2 pressure at 350 bars or 700 bars have been developed and used in trials. Today, a significant portion of the H2 cost arises from its delivery to end users. Due to the lack of an H2 infrastructure, it is not convenient for the public to use H2 at the moment, which seriously impedes the commercialization of fuel cells. 

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