hydrogen fuel cells

• generating electricity:

  • at anode, platinum catalyst splits hydrogen into protons and electrons
  • polymer electrolyte membrane only allows protons across, forcing electrons to travel around circuit
  • creates electric current in circuit
  • at cathode, oxygen combines with protons and electrons to make water
• advantages:

  • only waste product is water
  • twice as efficient as petrol
• hydrogen rich fuels:

  • methanol, natural gas or petrol
  • reformer converts them to hydrogen gas
  • only release small amounts of pollutants in fuel cell compared to conventional engine
• disadvantages: not easy to make cell

  • platinum and polymer electrolyte membrane expensive
  • production produces toxic waste
  • short life span
  • expensive to dispose
• disadvantages: storing hydrogen

  • explosive as a gas
  • very low boiling point so expensive to store as liquid
  • can be stored by adsorption or absorption but expensive and short life span
• disadvantages: manufacturing hydrogen

  • reacting natural gas with steam produces carbon dioxide
  • fossil fuels required to heat process
  • large amounts of electricity required for electrolysis of water
  • hydrogen is an energy carrier, as it requires energy to make it
• hydrogen economy: using hydrogen instead of oil for all energy needs
• disadvantages of a hydrogen economy:

  • concerns about safety and reliability of hydrogen
  • needs to be cheaper than current energy system but it's expensive to set up
  • clean, renewable energy sources required to manufacture hydrogen which are also expensive