A Hydrogen Economy. Dr. Mazen Abualtayef. Environmental Engineering Department. Islamic University of Gaza, Palestine

Transcription

1 A Hydrogen Economy Dr. Mazen Abualtayef Environmental Engineering Department Islamic University of Gaza, Palestine Adapted from a presentation by Professor S.R. Lawrence, Leeds School of Business, Environmental Studies, University of Colorado, Boulder, CO, USA

2 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

3 The Hydrogen H 2 Molecule

4 Hydrogen Economy Schematic

5 Hydrogen Economy in Hong Kong

6 Hydrogen Fueling Station

7 Hydrogen Systems

8 Hydrogen Energy Cycle

9 Hydrogen Production Cycle Crabtree et al., The Hydrogen Economy, Physics Today, Dec 2004

10 Operating the Hydrogen Economy Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28,

11 Hydrogen Economy Supply Chain

12 Hydrogen Pathways

13 Advantages of a Hydrogen Economy Waste product of burning H 2 is water Elimination of fossil fuel pollution Elimination of greenhouse gases Elimination of economic dependence Distributed production

14 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

15 Technological Questions Where does hydrogen come from? How is it transported? How is it distributed? How is it stored?

16 Producing Hydrogen

17 Current Hydrogen Production Current hydrogen production 48% natural gas 30% oil 18% coal 4% electrolysis Global Production 50 million tonnes / yr Growing 10% / yr US Production 11 million tonnes / yr Electrolysis 4% Coal 18% Oil 30% Natural Gas 48%

18 How is Hydrogen Produced? Reforming fossil fuels Heat hydrocarbons with steam Produce H 2 and CO Electrolysis of water Use electricity to split water into O 2 and H 2 High Temperature Electrolysis Experimental Biological processes Very common in nature Experimental in laboratories

19 Steam Reforming From any hydrocarbon Natural gas typically used Water (steam) and hydrocarbon mixed at high temperature ( C) Steam (H 2 O) reacts with methane (CH 4 ) CH 4 + H 2 O CO + 3 H kj/mol The thermodynamic efficiency comparable to (or worse than) an internal combustion engine Difficult to motivate investment in technology

20 Carbon Monoxide Reforming Additional hydrogen can be recovered using carbon monoxide (CO) low-temp (130 C) water gas shift reaction CO + H 2 O CO 2 + H kj/mol Oxygen (O) atom stripped from steam Oxidizes the carbon (C) Liberates hydrogen bound to C and O 2

21 Hydrogen Steam Reforming Plants

22 Electrolysis of Water (H 2 O)

23 Electrolysis of Water

24 Renewable Energy for Electrolysis

25 Biomass Electrolysis Module

26 High Temperature Electrolysis Electrolysis at high temperatures Use less energy to split water

27 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

28 Storing & Transporting Hydrogen

29 Hydrogen Storage Storage a major difficulty with hydrogen H 2 has low energy density per volume Requires large tanks to store H 2 can be compressed to reduce volume Requires heavy, strong tanks H 2 can be liquefied to reduce volume Both compression and liquefaction require a lot of energy

30 Ammonia Storage H 2 can be stored as ammonia (NH 3 ) 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

31 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

32 Transporting Hydrogen

33 Hydrogen Fueled Transport

34 Hydrogen-Powered Autos

35 Hydrogen-Powered Autos

36 Hydrogen-Powered Trucks

37 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).

38 Hydrogen-Powered Rockets

39 Implications of Hydrogen Transport Weight of fuel Weight of steel tank Weight of carbon fiber tank Volume of tank contents Volume of tank Typical 18 wheel truck (diesel) Typical sedan (gasoline) 1175 lb (small) NA 22.5 feet feet lb (small) NA 2.25 feet feet 3 Truck converted to ICE hydrogen 313 lb 31,300 lb 6,960 lb 67.5 feet feet 3 Sedan converted to hydrogen fuel cell 17.4 lb 1740 lb 387 lb 4 feet 3 9 feet 3

40 Problems with Hydrogen

41 Environmental Concerns 48% of hydrogen made from natural gas Creates CO 2 a greenhouse gas Hydrogen H 2 inevitably leaks from containers Creates free radicals (H) in stratosphere due to ultraviolet radiation Could act as catalysts for ozone depletion

42 Hydrogen vs. Methane Units Hydrogen Methane Density kg/m Gravimetric Energy MJ/kg Volumetric Energy MJ/m Bossel et al., The Future of the Hydrogen Economy: Bright or Bleak?, Oct 28,

43 Hydrogen Energy Losses Windmills generate electricity. Electricity converted to H 2 70% efficiency. H 2 compressed for pumping 20% energy loss H 2 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,

44 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,

45 The Promise of Hydrogen

46 UNIDO-ICHET Projection UNITED NATIONS INDUSTRIAL DEVELOPMENT ORGANIZATION INTERNATIONAL CENTRE FOR HYDROGEN ENERGY TECHNOLOGIES

47 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

48 Hydrogen Summary

49 Advantages of a Hydrogen Economy Waste product of burning H 2 is water Elimination of fossil fuel pollution Elimination of greenhouse gases Elimination of economic dependence Distributed production The stuff of stars

50 Disadvantages of Hydrogen Low energy densities Difficulty in handling, storage, transport Requires an entirely new infrastructure Creates CO 2 if made from fossil fuels Low net energy yields Much energy needed to create hydrogen