Primary Energy, Transmission and Infrastructure

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Primary Energy, Transmission and Infrastructure

• 11/15/2007

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Primary Energy Alternatives

• Nuclear
• Fossil
• Renewables
• Solar

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Nuclear Energy in the US

• 104 Operating Units
• 69 PWRs
• 35 BWRs
• 20 of the Electricity
• Operating Conditions
• PWR 325oC, 14 MPa
• BWR 290oC, 7 Mpa
• Fuel Enriched uranium

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Nuclear Energy in US
Source Energy Information Agency
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Current Nuclear Reactors and Hydrogen

• Temperatures too low
• For thermochemical cycles
• For high temperature electrolysis
• Power generation coupled to conventional alkaline
  electrolysis
• Efficiencies
• Power generation 32-34
• Electrolysis 80

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Nuclear Reactors Other Configurations

• Advanced BWRs, ESBWRs, AP1000
• No change in temperature/pressure
• Safety/operational features
• EPR European PW
• Standard design in France
• Fast Breeder Reactor
• Liquid metal (sodium) cooled
• Temperature 500oC

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Generation IV Reactors

• VHTR (Very High Temperature Reactor)
• GFR (Gas-cooled Fast Reactor)
• LFR (Lead-cooled Fast Reactor)
• MSR (Molten Salt Reactor)
• SFR (Sodium-cooled Fast Reactor)
• SCWR (Supercritical Water-cooled Reactor)

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VHTR

• Pebble bed modular reactor
• Prismatic modular reactor
• Helium cooled, graphite moderated, thermal
  reactor
• Outlet temperature 850-950oC
• High pressure coolant 5 MPa

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AHTR

• High temperature reactor like VHTR
• Molten salt (fluorides) coolant
• Li-Be fluoride
• Na-Zr fluoride
• Li-Na-K fluoride
• Atmospheric pressure
• Larger size (2400 MW) compared to VHTR (600 MW)

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Energy Transfer from Nuclear Reactor

• Electricity
• Thermal Energy
• Heat loss
• Safety aspects

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Expansion of Nuclear Energy Industry

• Needed if it is to be the primary energy source
• Global primary energy supply from nuclear energy
  624 Mtoe/yr (2004 data)
• Estimated need for hydrogen transport
  applications in 2050 6800-15000 Mtoe/yr
• Proven reserves 45000-195000 Mtoe

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Assumptions

• Annual Hydrogen transportation demand 1 Gton
• All vehicles use fuel cell engine, efficiency 50
• How long will the reserves last if all
  applications use nuclear as the primary energy
  source?

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Fossil Energy

• Coal, natural gas, oil
• Proven reserves (in Mtoe)
• Coal 448,000
• Natural gas 161,000
• Oil 162,000
• Hydrogen for transportation (2050)
• 6250, 3250, and 3900 respectively (in Mtoe)

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Coal Technologies

• Co-generation of hydrogen and electricity in coal
  gasifiers
• With carbon capture and sequestration systems
• Fossil energy will play a significant part for a
  few decades

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Renewables

• Hydropower
• Wind Energy
• Geothermal
• Solar
• Photovoltaic
• Thermal
• Biomass
• Hydrogen primarily through electricity

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Capacity Increase Needed

• Solar Photovoltaic 21,000
• Geothermal 1250
• Wind 900
• Solar thermal 500
• Hydropower 25
• Biomass 10

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Biomass

• Clean and available
• Carbon neutral
• Sources
• Energy Crops
• Corn, sugarcane (bioethanol)
• Sunflower, rapeseed (biodiesel)
• Lignocellulosic
• Organic wastes domestic, industrial, agricultural

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Biomass Utilization

• Transformation into bioethanol or biodiesel
• USA Corn
• Brazil Sugarcane
• Gasification to syngas and biomethanol/hydrogen

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Biomass Availability

• Diversion of crops from alimentary purposes to
  energy production
• Cultivable land area
• Lignocellulosic biomass conversion
• Cellulose-to-bioethanol

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Can we afford biofuels?

• Resource requirements
• Land
• Water
• Other
• Greenhouse emissions spike
• Loss of tropical forests
• Draining of swamps

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Solar Energy

• Incident solar energy 178,000 TW/y
• Global energy demand 13 TW/y (2000)
• Relatively evenly distributed, in comparison to
  geothermal, wind and hydroelectric energy
• Average surface irradiation 300 W/sq.m. in
  temperate climes, 650 W/sq.m. in desert

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Area Requirements

• 400,000 sq. km. for 13 TW/y
• High irradiance
• Capture efficiency 12
• Approximately 400 x 400 miles
• Only 4.4 of Sahara desert

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Hydrogen Transmission and Distribution

• Pipelines
• Compressed Gas
• Liquid Hydrogen
• Chemical Compounds
• Container Transport
• Tankers
• Railroad tank cars
• Air Transport
• Sea Transport

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Hydrogen Pipelines in World
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Hydrogen Pipelines

• Gaseous hydrogen
• Leakage through joints, fittings, valves etc. of
  concern
• Natural gas vs. Hydrogen Pipelines
• Reciprocal compressors preferred for hydrogen
  service
• Larger diameter and more compression power needed
  for hydrogen for equivalent energy transfer
• Large Scale Hydrogen transmission 50-80 more
  expensive than the natural gas

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Hydrogen Compression

• Centrifugal compressors not as effective as
  reciprocal compressors
• Recirculation of hydrogen within the compressor
• Natural Gas Centrifugal Compressors not useful
  for hydrogen
• Lower compression ratio
• Larger number of stages

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Reciprocal Compressors

• Natural Gas compressors can be used for hydrogen
• Seals need to be improved
• Material should be adapted to hydrogen

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Hydrogen vs. Natural Gas Transmission

• 1000 MW Thermal Output
• Hydrogen
• 330,000 Nm3/h
• 500 mm diameter pipeline
• Natural Gas
• 92,000 Nm3/h
• 400 mm diameter pipeline
• More compression power needed for hydrogen

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Liquid Hydrogen Pipelines

• Energy needed for liquefaction
• Hydrogen should be transferred as para-hydrogen
• Cryogenic lines, super-efficient vacuum
  insulation required
• Minimize the heat leakage
• Single phase flow regime should be maintained
• Supersonic conditions may be reached in two-phase
  flow leading to increased flow resistance and
  line vibration

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Liquid Hydrogen Pipeline

• Concentric Pipes
• Outer tube diameter up to 2.5 times in the inner
  tube diameter
• High Vacuum (10-6 torr) in the annular space
• Low emissivity of the materials to minimize
  radiative heat transfer
• Activated carbon adsorbent in the annular space
  to adsorb residual gas
• Structural material commonly used Cr18Ni9Ti

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Chemical Energy Transmission Systems (CETS)
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CETS

• Steam reforming
• CO2 reforming
• Methanol
• Methyl Cyclohexane-Toluene
• Cyclohexane-Benzene
• Ammonia
• Others?

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Steam Reforming Loop

• EVA Einzelspaltrohr-VersuchsAnlage
• Steam reforming of methane
• CH4 H2O ? CO 3H2
• CO H2O ? CO2 H2

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Steam Reforming Loop

• ADAM Anlage mit Drei Adiabaten
  Methanisierungsreaktoren
• Synthesis Gas ? Methane Water
• Transported Power
• EVA/ADAM 300 kW
• EVA-II/ADAM-II 5 MW

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EVA-ADAM System
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Other CETS

• Transfer as (primarily) hydrogenated liquid
• Extract hydrogen via dehydrogenation at the
  delivery point
• Cyclohexane-Benzene System
• 3H2 C6H6 ? C6H12
• High density of hydrogen
• Hydrogenation/Dehydrogenation reaction steps at
  origin and destination

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Cyclohexane-Benzene System
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CETS

• Methylcyclohexane-Toluene System
• 3H2 C7H8 ? C7H14
• Methanol
• CH3OH H2O ? CO2 3H2
• Ammonia
• 2NH3 ? N2 3H2
• CO2 Reforming
• CH4 CO2 ? 2CO 2H2

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Comparison CETS and other Modes
Cacciola et al, Int. J. Hydrogen Energy 1985,
10325-31
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CETS and Other Modes Efficiency Comparison
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Container Transport

• Liquid Hydrogen Containers
• Cryogenic double hull tanks
• Capacity up to 60 m3
• Boil-off losses
• Emptying through controlled heating rather than
  discharge pumps
• Suitable for medium-scale installations (a few
  thousand m3 per day)

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Containerized Gas Transport

• Pressurized cylindrical vessels
• 200 bar pressure
• Arranged in frames adapted to road transport
• Frame capacity up to 3000 m3
• Strict regulations for public safety

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Rail Transport

• Similar to road transport of gaseous or liquid
  hydrogen
• Large load hauled per trip due to the size of
  tank car
• Fewer trips and fillings
• Smaller evaporation losses

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Liquid Hydrogen Transport at Sea

• Sea Transport of LNG common
• Sea Transport of Liquid Hydrogen in Cryogenic
  Tanks for Supply to the French Space Station in
  Guiana
• Euro-Quebec Hydro-Hydrogen Pilot Project
  Transport of liquid hydrogen in five 3000 m3
  tanks on a ship
• Storage/Transportation accounting for 40 of the
  cost of hydrogen

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Liquid Hydrogen Transport by Air

• Avoid boil-off losses in sea transport
• Low density of hydrogen compatible with air
  transport
• Reduced heat leakage into air container during
  flight
• Delivery time significantly reduced
• Negligible pressure and temperature rise during
  the transport
• Large air transport system needs to be developed

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Container Transport

• Railway tank cars possibly more efficient than
  road transport
• Gaseous/liquid tankers for localized
  distribution Pipelines more efficient for long
  distances
• Potential air transport using superjumbo jets

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Hydrogen vs. Electricity

• Electricity
• versatile,
• superior energy carrier
• High exergy
• Electricity Transmission
• Underground/overhead
• DC/AC
• 40-765 kVAC lines

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Transmission Comparison

• Hydrogen Pipelines
• Compression energy needed
• Diffusion leakage losses
• Frictional losses
• Electrical Transmission
• Power conversion losses at sending and receiving
  ends
• Transmission line losses

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Best Mode of Transmitting Energy (?)
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Transmission Penalty
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Infrastructure Requirements

• Hydrogen Storage
• Ability to manage the mismatch between production
  (supply) and consumption (demand)
• Easy for solid-liquid fuels
• Underground/intermediate storage containers used
  for natural gas
• Limited capacity for storage of electrical energy

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Hydrogen Storage

• Most likely as compressed gas
• Energy penalty in liquefaction
• Chemical storage (hydrides, etc.) uneconomical
• Cheap storage options needed
• Underground storage
• Lower pressure storage of hydrogen (compared to
  natural gas)

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Decentralized Storage of Hydrogen

• Industrial Use
• Experience in petrochemical/chemical industry
• Commercial/Residential
• Safety considerations
• High pressure or cryogenic storage may be
  undesirable
• Metal hydride/Adsorbed hydrogen?

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Transmission Infrastructure

• Use of natural gas pipeline network for hydrogen
  transmission
• Pipes would be usable
• Capacity will be lower
• Fittings, valves, auxiliary equipment
  (compressors) need replacement
• Loading up to10 hydrogen in natural gas has no
  detrimental economic impact
• Simultaneous use of natural gas and hydrogen?

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Distribution Infrastructure

• Distribution through existing local natural gas
  lines?
• Residential use of hydrogen?
• Hydrogen filling stations
• Number of stations
• Vehicle range?