Meeting Minutes 4/18/12: Hydrogen as Fuel

  • The big picture:
    • Hydrogen is the most abundant element in the universe.
    • It is the 8th most abundant element on Earth.
      • Earth has insufficient gravity to maintain free hydrogen.
  • Chemical Reactions:
    • Combustion
    • Electrolysis
    • Steam Methane Reforming
    • Hydrocracking (uses H2 to break carbon chains)
    • Haber process (uses H2 to produce ammonia)
  • Hydrogen as fuel:
    • Hydrogen can be burned just like natural gas
    • Fuel cells
      • Produce electricity at a 40-50% efficiency.
      • Have a combined heat & power 70-95% efficiency.
      • Protons are separated from electrons by a membrane which creates a potential.
      • Use a 0.7 V/cell.
      • Made of stacks of cells
      • Catalysts
        • Platinum-based is the traditional
        • carbon- or nickel-based
  • Hydrogen Stroage
    • The good news: Hydorgen has more energy per gram capacity than traditional fuels
    • The bad news: Its density is much less than traditional fuels, so it is less useful in that respect
    • Current Technologies
      • liquid hydrogen
        • energy cost 30%
        • expensive
        • boil-off losses ~ 50% in 10 days
      • compressed hydrogen
        • energy cost 15-20%
        • low energy density
        • heavy
        • potentially dangerous due to high pressures (~700bar)
      • metal hydrides
        • minimal energy cost, dense hydrogen packing
        • very heavy
        • expensive (because of the use of rare metals)
        • useful for small scale, not large scale
      • chemical conversion
        • using water or ammonia
    • When volume is not an issue, hydrogen storage is very useful
      • however, we still need a breakthrough
  • Prodction
    • Steam methane reforming
      • 95% of H2 supply
      • efficiency ~70%
      • releases CO2
    • Electrolysis
      • fuel cell rxn in reverse
      • efficiency 60-8-%
      • can pressurize within electrolyzer
    • Anaerobic digestion (@ OSU)
      • consumes organic waste
    • Biomass gasification
      • produces H2 and CO2
    • Photobiological hydrogen (@ OSU)
      • algae and cyanobacteria
      • photosynthesis splits water
      • light provides energy input
      • hydrogenase catalyst
    • Artificial Photolysis
      • using light energy to split water
      • Micro scale PV electrolysis
    • Thermochemical Cycles (@ OSU with Dr. Yokochi)
      • coupled rxn loop
      • heat input from concentrated solar
  • Safety with hydrogen
    • Nearly invisible flame in daylight
    • Hydrogen embrittlement of metals
    • 5-75% flammable mixture in air
    • Low activation energy
    • Lighter than air, so dissipates rapidly in the atmosphere
    • Overall, no more dangerous than gasoline or natural gas if handled properly.
  • Hydrogen’s role in the Future
    • Abundant Carbon-free Energy?
      • Universal energy currency
      • Fuel cell cars
      • Hydrogen homes
      • Drinkable exhaust
    • Or Oil-company Conspiracy?
      • Technology will never be ready
      • Inferior to EV’s from green perspective
      • Favored by policy
      • Produced from fossil fuel
  • Greatest demand right now is energy storage.
    • Hydrogen, pumped hydroelectric, compressed air energy storage (CAES)
    • Pumped hydro: best option but site-limited
    • CAES has slightly higher round-trip efficiency
  • Vestenskov, Denmark is the world’s first hydrogen-powered community
    • surplus wind electricity is stored as hydrogen and distributed
  • Energy density is currently the #1 challenge
    • But the future is wide open
    • It will be a race between electric and hydrogen vehicles
  • The OSU Hydrogen Trailer
    • This spring, they will acquire an electrolyzer
    • Hydrogen Club meetings are Mondays 4-6, people are welcome!
  • DOE project @ OSU
    • Brian Paul MechE
    • Goran Jovanic ChemE