Density and Storage

• Hydrogen storage requires special handling.Jupiterimages/Photos.com/Getty Images
  
  Each pound of hydrogen contains three times the energy of a gallon of gasoline but requires four times the space. A vehicle with a 12-gallon tank would require a 48-gallon tank of hydrogen to provide the same amount of energy. Hydrogen tanks create not only a storage problem, but a potentially catastrophic situation if punctured. Long-term storage is another issue, as for safety reasons, liquid hydrogen must be allowed to evaporate. This results in the loss of half the fuel in a just two weeks even if a vehicle is not used.
  
  

Production

• Production of hydrogen typically requires use of fossil fuels.Thomas Northcut/Photodisc/Getty Images
  
  Unlike fossil fuels, hydrogen cannot be mined but must be produced. Natural gas is the most commonly used feedstock. The process, known as steam methane reformation, separates natural gas into hydrogen and carbon oxides. The oxide greenhouse gases are released into the atmosphere. Another way to extract hydrogen is to take water and break it down into oxygen and hydrogen through electrolysis. This process require electricity, the majority of which is created through the use of fossil fuels.
  
  

Infrastructure and Transportation

• Hydrogen pipelines are more expensive than oil pipelines.Jupiterimages/Photos.com/Getty Images
  
  Transporting hydrogen by rail or truck is inefficient. Popular Mechanics estimates that a truck that normally carries enough fuel for 800 cars can only carry enough hydrogen to fuel 80. Hydrogen pipelines can deliver high volumes of energy but require special materials and construction techniques that make them expensive to build and maintain. Generating hydrogen at the point of need, such as a filling station, requires large amounts of electricity.
  
  

Economic Realities

• A PEM fuel cell costs about $36,000.Jupiterimages/Photos.com/Getty Images
  
  The large amounts of energy required to produce, store, transport, and convert hydrogen into useful power means that hydrogen is expensive and wasteful. Lisa Zyga estimates that only 25 percent of hydrogen is left for practical use after all factors are considered. A massive investment for infrastructure will be required if hydrogen is ever to be a practical alternative fuel. Energy companies will be hesitant to build infrastructure before hydrogen vehicles are common. Consumers will be hesitant to buy vehicles before the infrastructure is in place.