"A Hydrogen Economy"
A Hydrogen Economy Agenda • A Hydrogen Vision of the Future • Hydrogen Systems • Producing Hydrogen • Storing and Transporting Hydrogen • Hydrogen Fueled Transport • Problems with Hydrogen • The Promise of Hydrogen • Hydrogen Summary A Vision of a Hydrogen Future "I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. I believe then that when the deposits of coal are exhausted, we shall heat and warm ourselves with water. Water will be the coal of the future." Jules Vernes (1870) L´île mystérieuse The Hydrogen H2 Molecule http://planetforlife.com/h2/index.html Hydrogen Economy Schematic Hydrogen Economy in Hong Kong http://www.gii.com.hk/eng/clean_energy.htm Hydrogen Fueling Station Hydrogen Systems Hydrogen Energy Cycle http://en.wikipedia.org/wiki/Hydrogen_economy Hydrogen Production Cycle Crabtree et al., “The Hydrogen Economy,” Physics Today, Dec 2004 Operating the Hydrogen Economy Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Hydrogen Economy Supply Chain Hydrogen Pathways http://www.ch2bc.org/index2.htm Advantages of a Hydrogen Economy • Waste product of burning H2 is water • Elimination of fossil fuel pollution • Elimination of greenhouse gases • Elimination of economic dependence • Distributed production http://www.howstuffworks.com/hydrogen-economy.htm Issues with Hydrogen • Not widely available on planet earth • Usually chemically combined in water or fossil fuels (must be separated) • Fossil fuel sources contribute to pollution and greenhouse gases • Electrolysis requires prodigious amounts of energy Technological Questions • Where does hydrogen come from? • How is it transported? • How is it distributed? • How is it stored? http://www.howstuffworks.com/hydrogen-economy.htm Producing Hydrogen Current Hydrogen Production •Current hydrogen production •48% natural gas Electrolysis 4% •30% oil Coal 18% •18% coal Natural Gas • 4% electrolysis 48% •Global Production Oil •50 million tonnes / yr 30% •Growing 10% / yr •US Production •11 million tonnes / yr How is Hydrogen Produced? • Reforming fossil fuels • Heat hydrocarbons with steam • Produce H2 and CO • Electrolysis of water • Use electricity to split water into O2 and H2 • High Temperature Electrolysis • Experimental • Biological processes • Very common in nature • Experimental in laboratories http://www.howstuffworks.com/hydrogen-economy.htm Steam Reforming • From any hydrocarbon • Natural gas typically used • Water (steam) and hydrocarbon mixed at high temperature (700–1100 °C) • Steam (H2O) reacts with methane (CH4) • CH4 + H2O → CO + 3 H2 - 191.7 kJ/mol • The thermodynamic efficiency comparable to (or worse than) an internal combustion engine • Difficult to motivate investment in technology Carbon Monoxide Reforming • Additional hydrogen can be recovered using carbon monoxide (CO) • low-temp (130°C) water gas shift reaction • CO + H2O → CO2 + H2 + 40.4 kJ/mol • Oxygen (O) atom stripped from steam • Oxidizes the carbon (C) • Liberates hydrogen bound to C and O2 Hydrogen Steam Reforming Hydrogen Steam Reforming Plants Electrolysis of Water (H2O) http://www.gm.com/company/gmability/edu_k-12/9-12/fc_energy/make_your_own_hydrogen_results.html Electrolysis of Water http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/electrol.html Renewable Energy for Electrolysis http://www.howstuffworks.com/hydrogen-economy4.htm Biomass Electrolysis Module http://www.nrel.gov/hydrogen/photos.html High Temperature Electrolysis • Electrolysis at high temperatures • Use less energy to split water http://en.wikipedia.org/wiki/Hydrogen_economy Biological H2 Creation •Nature has very simple methods to split water •Scientists are working to mimic these processes in the lab; then commercially Crabtree et al., “The Hydrogen Economy,” Physics Today, Dec 2004 Storing & Transporting Hydrogen Hydrogen Storage • Storage a major difficulty with hydrogen • H2 has low energy density per volume • Requires large tanks to store • H2 can be compressed to reduce volume • Requires heavy, strong tanks • H2 can be liquefied to reduce volume • Boils at -423 °F (cryogenic) • Requires heavily insulated, expensive tanks • Both compression and liquefaction require a lot of energy Ammonia Storage • H2 can be stored as ammonia (NH3) • Exceptionally high hydrogen densities • Ammonia very common chemical • Large infrastructure already exists • Easily reformed to produce hydrogen • No harmful waste • BUT • Ammonia production is energy intensive • Ammonia is a toxic gas Metal Hydride Storage • Metal hydrides can carry hydrogen • Boron, lithium, sodium • Good energy density, but worse than gas • Volumes much larger than gasoline • Three times more volume • Four times heavier • Hydrides can react violently with water • Leading contenders • Sodium Borohydride • Lithium Aluminum Hydride • Ammonia Borane Alkali Prod. Energy vs. Instrinsic Energy Energy needed to produce alkali metal hydrides relative to the energy content of the liberated hydrogen. Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Transporting Hydrogen Storing & Transporting Hydrogen • Store and Transport as a Gas • Bulky gas • Compressing H2 requires energy • Compressed H2 has far less energy than the same volume of gasoline • Store and Transport as a Solid • Sodium Borohydride • Calcium Hydride • Lithium Hydride • Sodium Hydride http://www.howstuffworks.com/hydrogen-economy.htm Hydrogen Fueled Transport Hydrogen-Powered Autos Hydrogen-Powered Autos http://planetforlife.com/h2/h2vehicle.html Hydrogen-Powered Trucks http://planetforlife.com/h2/h2vehicle.html Hydrogen-Powered Aircraft Hydrogen powered passenger aircraft with cryogenic tanks along spine of fuselage. Hydrogen fuel requires about 4 times the volume of standard jet fuel (kerosene). http://planetforlife.com/h2/h2vehicle.html http://aix.meng.auth.gr/lhtee/projects/cryoplane/ Hydrogen-Powered Rockets http://planetforlife.com/h2/h2vehicle.html Implications of Hydrogen Transport Weight Weight of Volume of Weight Volume of steel carbon tank of fuel of tank tank fiber tank contents Typical 18 wheel 24.0 1175 lb (small) NA 22.5 feet3 truck (diesel) feet3 Typical sedan 108 lb (small) NA 2.25 feet3 2.5 feet3 (gasoline) Truck converted 313 lb 31,300 lb 6,960 lb 67.5 feet3 157 feet3 to ICE hydrogen Sedan converted to hydrogen fuel 17.4 lb 1740 lb 387 lb 4 feet3 9 feet3 cell http://planetforlife.com/h2/h2swiss.html Problems with Hydrogen Environmental Concerns • 48% of hydrogen made from natural gas • Creates CO2 – a greenhouse gas • Hydrogen H2 inevitably leaks from containers • Creates free radicals (H) in stratosphere due to ultraviolet radiation • Could act as catalysts for ozone depletion H2 Energy Densities Crabtree et al., “The Hydrogen Economy,” Physics Today, Dec 2004 Energy Densities for Various Fuels Higher Heating Value (HHV) is a measure of energy Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm H2 and Energy Density for Various Fuels Hydrogen density and HHV energy content of ammonia and selected synthetic liquid hydrocarbon fuels Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Hydrogen vs. Methane Units Hydrogen Methane Density kg/m3 0.0887 0.707 Gravimetric Energy MJ/kg 142.0 55.6 Volumetric Energy MJ/m3 12.7 40.0 Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Liquifaction Energy vs. Intrinsic Energy Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Hydrogen Storage Densities Crabtree et al., “The Hydrogen Economy,” Physics Today, Dec 2004 Hydrogen Energy Losses • Windmills generate electricity. • Electricity converted to H2 – 70% efficiency. • H2 compressed for pumping – 20% energy loss • H2 pumped long distance – 30% loss • 65% loss to Europe from the Sahara). • Loss at filling stations – assume 5% • Loss in fuel cell – 50% (possibly only 40%) • Combining losses → only 15-18% useful electricity, or vehicle motor power • 9.3% in the case of the Sahara Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Criticism of Hydrogen Economy • Hydrogen economy idea does not work for multiple reasons. • No practical source of cheap hydrogen • No good way to store hydrogen • No good way to distribute hydrogen • Problems with physical & chemical properties of hydrogen • Technology cannot change these facts. • Compact / convenient future energy carrier needed • Methane, ethane, methanol, ethanol, butane, octane, ammonia, etc. are better energy carriers. • Difficult to understand the enthusiasm for hydrogen • Hydrogen does not solve the energy problem and it is a bad choice for carrying energy. Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Elemental Hydrogen Economy Elemental Hydrogen Economy based on the natural cycle of water. Elemental hydrogen is provided to the user Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm Synthetic Liquid Hydrocarbon Economy A Synthetic Liquid Hydrocarbon Economy may be based on the two natural cycles of water and carbon dioxide. Natural and synthetic liquid hydrocarbons are provided to the user. Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28, 2004 http://www.oilcrash.com/articles/h2_eco.htm The Promise of Hydrogen UNIDO-ICHET Projection UNITED NATIONS INDUSTRIAL DEVELOPMENT ORGANIZATION INTERNATIONAL CENTRE FOR HYDROGEN ENERGY TECHNOLOGIES http://www.unido-ichet.org/ICHET-transition.php The Iceland Example • Iceland committed to be the first hydrogen economy • 2050 goal • Will use geothermal resources to create hydrogen • Power autos, buses, and fishing fleet with hydrogen http://en.wikipedia.org/wiki/Hydrogen_economy Hydrogen Summary Advantages of a Hydrogen Economy • Waste product of burning H2 is water • Elimination of fossil fuel pollution • Elimination of greenhouse gases • Elimination of economic dependence • Distributed production • The stuff of stars http://www.howstuffworks.com/hydrogen-economy.htm Disadvantages of Hydrogen • Low energy densities • Difficulty in handling, storage, transport • Requires an entirely new infrastructure • Creates CO2 if made from fossil fuels • Low net energy yields • Much energy needed to create hydrogen • Possible environmental problems • Ozone depletion (not proven at this point) Extra Slides Energy Density of Hydrogen Current Uses of Hydrogen Thermochemical Production Problems with Hydrogen Prospects for the Future http://www.howstuffworks.com/hydrogen-economy.htm The Hydrogen Vision