Energy and the New Reality, Volume 2:
C-Free Energy Supply
Chapter 10: The Hydrogen Economy
L. D. Danny Harvey
harvey@geog.utoronto.ca
Publisher: Earthscan, UK
Homepage: www.earthscan.co.uk/?tabid=101808
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Figure 10.1 Efficiency of steam methane reforming to
produce hydrogen
Theoretical
80
60
40
S=2
20
S=3
S=4
0
500
600
700
800
900
1000
Reforming T (o C)
Source: Lutz et al (2003, International Journal of Hydrogen Energy 28, 159–167, http://www.sciencedirect.com/science/journal/03603199)
Figure 10.2 Capital cost of steam methane reformers
1200
$6000/kW
$3000/kW
1000
Cost (1000$)
$1500/kW
800
600
400
$1500/kW
Industry
200
Literature
0
0
5
10
15
20
25
Capacity (kg/hr)
Source: Modified from Weinert and Lipman (2006, An Assessment of Near-Term Costs of Hydrogen Refueling Stations
and Station Components, Institute of Transportation Studies, UC Davis)
Figure 10.3 Capital cost of electrolyzers
1000
$6000/kW
800
Cost (1000$)
$3000/kW
600
400
$1500/kW
Industry
200
Literature
0
0
2
4
6
8
10
Capacity (kg/hr)
Source: Modified from Weinert and Lipman (2006, An Assessment of Near-Term Costs of Hydrogen Refueling Stations
and Station Components, Institute of Transportation Studies, UC Davis)
Figure 10.4 Contributions to the total electrolysis
voltage as a function of current density
2.0
"Thermo-neutral" electrolysis voltage (1.48 V)
Cathode activation
Electrolysis Voltage, V
1.8
Anode activation
1.5
Electrolyte Resistance
1.3
1.0
0.8
Theoretical Minimum Voltage for Water Electrolysis
0.5
0.3
0.0
0
1
2
3
4
5
6
Current Density (kA/m 2)
7
8
9
10
Source: Berry et al (2003a, Encyclopedia of Energy, Elsevier 3, 253-265, http://www.sciencedirect.com/science/referenceworks/9780121764807)
Figure 10.5 Typical variation of electrolysis efficiency with load
100
Efficiency (%)
95
90
85
80
75
70
0
20
40
60
80
100
Load (as a percentage of nominal power input)
Source: Ntziachristos et al (2005, Renewable Energy 30, 1471–1487, http://www.sciencedirect.com/science/journal/09601481)
120
Figure 10.6 Variation with operating temperature of
the energy inputs required for electrolysis
300
Energy Input (kJ/mol H2)
250
200
150
Electrical energy input
Thermal energy input
Total energy input
100
50
0
200
400
600
800
1000
Temperature (oC)
Source: Ni et al (2007, International Journal of Hydrogen Energy 32, 4648–4660, http://www.sciencedirect.com/science/journal/03603199)
Figure 10.7 Solar H2 production through hightemperature electrolysis
H2 O
100 units
Heat
Thermal Electricity
Engine
Electrolyzer
50 units
Solar
Thermal
Collectors
= 0.50
Waste Heat
Heat
H2 ,
= 0.47
H2 , 24 units
O2
Figure 10.8 PEC Structure
Source: Bak et al (2003, International Journal of Hydrogen Energy 27, 991-1022, http://www.sciencedirect.com/science/journal/03603199)
Figure 10.9 Energy required to compress hydrogen
12
Compressional Energy (% of H2 LHV))
Adiabatic H2:CH4
20
10
Series7
Compressional
Series5
Energy
Series6
Adiabatic
Actual
Isothermal
16
12
8
6
8
4
4
2
0
0
1000
0
200
400
600
Final Pressure (atm)
800
Ratio of H2:CH4 Compressional Energies
24
Figure 10.10 Energy required to transmit natural gas
and H2 by pipeline
70
Transit Energy/Delivered Energy (%)
Hydrogen, same D as for methane
60
Hydrogen, same V as for methane
Methane
50
40
30
20
10
0
0
1000
2000
3000
Distance (km)
4000
5000
Figure 10.11 Cost of transmitting various a mixture consisting of
various proportions of natural gas and hydrogen,
as a function of pipe diameter
4
Transmission Cost ($/GJ)
Series7
H2 Fraction
0.0
0.2
0.4
0.6
0.8
1.0
3
2
1
0
0.1
0.3
0.5
0.7
0.9
Pipe Diameter (m)
1.1
1.3
1.5
Source: Oney et al (1994 , International Journal of Hydrogen Energy 19, 813–822, http://www.sciencedirect.com/science/journal/03603199)
Figure 10.12a Hydrogen Aircraft
60
50
Operating Empty Weight
Percent Change in Weight
Maximum Take-Off Weight
40
30
20
10
0
-10
-20
Business Small Regional Regional MediumJet
Regional Propeller
Jet
Range
Aircraft Aircraft Aircraft Aircraft
LongRange
Aircraft
VeryLongRange
Aircraft
Source: Airbus (2003, Liquid Hydrogen Fuelled Aircraft – System Analysis. Final Technical Report (Publishable Version), Airbus
Deutschland GmbH (Project Coordinator) Project No GRd1-1999-10014, www.aero-net.org)
Percent Change in Fuel Consumption
Figure 10.12b Hydrogen Aircraft
40
30
20
10
0
Business Small Regional Regional Medium- LongJet
Regional Propeller
Jet
Range
Range
Aircraft Aircraft Aircraft Aircraft Aircraft
VeryLongRange
Aircraft
Source: Airbus (2003, Liquid Hydrogen Fuelled Aircraft – System Analysis. Final Technical Report (Publishable Version), Airbus
Deutschland GmbH (Project Coordinator) Project No GRd1-1999-10014, www.aero-net.org)
Figure 10.13 Cost of H2 produced by steam reforming
of natural gas or by electrolysis of water
40
Cost of Hydrogen ($/GJ)
35
Electrolysis of Water, CF=0.25
CF=0.9
30
Steam Reforming
of Natural Gas
25
20
15
10
5
0
0
2
4
6
8
Cost of Electricity (cents/kWh)
0
4
8
12
Cost of Natural Gas ($/GJ)
16
Figure 10.14 Cost of gas transmission vs. energy flow rate
3.0
Cost of Transmission ($/GJ)
2.5
Natural Gas
2.0
Hydrogen
1.5
1.0
0.5
0.0
0
200
400
Energy Flow Rate (1000s GJ/day)
Source: Ogden, J. M. (1999, Annual Review of Energy and the Environment 24, pp227–279)
600
25
62
20
$2.0/litre
15
52
42
$1.5/litre
32
10
$1.0/litre
22
`
5
0
1000
12
2000
3000
4000
Upfront Cost Premium ($)
2
5000
Allowed Hydrogen Cost ($/GJ)
Allowed Hydrogen Cost (cents/kWh)
Figure 10.15 Cost of H2 that just offsets (through reduced fuel
costs) the increased purchase cost of H2-powered vehicle over a
10-year operating life for gasoline at $1.0/itre to $2.0/litre