Co-Production of Hydrogen and Electricity
(GHG/07/42)
• Hydrogen may be used in future as an energy carrier
• In the long term it is expected that hydrogen will be made
using renewable energy
• In the medium term fossil fuels with CO2 capture are
expected to be the lowest cost option
• A study was undertaken to assess production of hydrogen
and electricity by coal gasification with CO2 capture
• Study undertaken by Foster Wheeler Italiana
• Report 2007/13, September 2007
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Hydrogen and Electricity Co-Production
CO2
compression
CO2
Sulphur
Coal
Gasification
Shift
conversion
Acid gas
removal
Oxygen
H2S
Hydrogen
separation
Sulphur
recovery
Hydrogen
Air
Air
separation
Nitrogen
Combined
cycle
Air
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Power
Air
Plant Performance and Costs
• Screening assessment of gasifiers and acid gas removal
processes
• Shell, Siemens and GE gasifiers
• Little difference in overall costs
• Selexol and Rectisol acid gas removal
• Shell gasifier and Selexol were selected
• Estimates of performance and costs of plants
•
•
•
•
•
Electricity, without CO2 capture
Electricity, with capture
Hydrogen, with capture (+ electricity for internal consumption)
Electricity and hydrogen co-production (fixed ratio), with capture
Electricity and hydrogen co-production (variable ratio), with capture
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Plant Performance and Costs
• Electricity-only IGCCs
• Capital cost of plant with CO2 capture is €2380/kW
• Cost of electricity with capture is €0.072/kWh
• Cost of avoiding emissions is €31/tonne CO2
• Costs are higher than in the past (higher materials costs etc)
• Hydrogen-only plant
• Cost of hydrogen is € 9.45/GJ
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Plant Performance and Costs
• Co-production plants (fixed H2: electricity ratio)
• Co-production reduces costs compared to electricityonly and hydrogen-only plants
• About 4% overall
• Flexible co-production plants
• H2:electricity ratio can be varied from 1.3 to 3.1:1
• Coal gasifiers and gas turbine remain fully loaded
• Flexibility increases the capital cost by 1%
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Scenario Modelling
• The aim of the scenario modelling was to quantify benefits
of flexible co-production
• Hydrogen and electricity demands were specified
• Based on current Netherlands and USA energy
consumptions
• Hydrogen was assumed to be used to replace vehicle fuels
and a fraction of natural gas used by small consumers
• Current nuclear and renewable electricity supply was
assumed to be retained
• Monthly net electricity and hydrogen demands were
calculated (also daily for the Netherlands)
• Emphasise that these are hypothetical scenarios
• Predicting future energy systems is very complicated
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Electricity and Hydrogen Demands
(Jan hydrogen demand = 100) .
Relative energy demand
120
100
Netherlands
Hydrogen
80
Netherlands
Electricity
60
USA Hydrogen
40
USA Electricity
20
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
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Scenario Modelling
• Five plant scenarios were modelled
• Without hydrogen storage
• Electricity-only and hydrogen-only plants
• Including non-flexible co-production plants
• Including flexible co-production plants
• With underground buffer storage of hydrogen
• Non-flexible co-production plants
• Flexible co-production plants
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Scenario Results
Relative cost of electricity .
100
90
Netherlands
80
USA
70
60
Electricity and Non-flexible
Non-flexible
hydrogen-only co-production co-production
no storage
w ith storage
Flexible coproduction
no storage
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Flexible coproduction
w ith storage
Conclusions
• Hydrogen can be co-produced in IGCC plants with CO2
capture
• The electricity : hydrogen output ratio can be adjusted
• Varying hydrogen and electricity demands can be satisfied
• Gasifiers can be operated at full load
• Practical advantage: fewer operating problems
• Economic advantage: better utilisation of capital investment
• The lowest cost option is to use flexible co-production
plants with underground buffer storage of hydrogen
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Recommendations
• Costs of abating CO2 emissions from small stationary
sources by CCS or by using energy carriers (hydrogen or
electricity) from large plants with CCS should be
compared
• Proposal 32-11 was submitted but received insufficient
votes
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