Wasserstoff als Energiespeicher - TU Berlin...Wasserstoff als Energiespeicher Peter Strasser TU...
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1 Wasserstoff als Energiespeicher Peter Strasser TU Berlin
Transcript of Wasserstoff als Energiespeicher - TU Berlin...Wasserstoff als Energiespeicher Peter Strasser TU...
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Wasserstoff als EnergiespeicherPeter Strasser
TU Berlin
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The global decarbonization
Carbon/Hydrogen ratio approaching zero over human historyHydrogen offers high energy density
1830
4453
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Wood Coal Petroleum Natural Gas Hydrogen
MJ/
kg
C
……C
H
H
HH
HH HH
Carbon/Hydrogenratio: ∞ ∞ ½ ¼ 0
CC
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
H
C
H
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Water Splitting by Electrolysis
• Ru/Ir electrocatalysts very expensive• Oxygen evolution slow losses !• H2 / O2 extremely pure• Production at high pressures possible• Scalable – efficiency independent of size !
Rafn, Nyt Bibl. Phys. Med. Oec. I, 28 (1801).
Ritter, Oersted Modern ElectrolyzerH2
O2
2 H2O + electricity 2 H2 + O2
Source: Norsk Hydro
40-50 kWh -> 1 kg H2 ~ 4l gasoline
Electrical energy Chemical energy
Pt
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Today’s Hydrogen Storage Technologies
• ElementalCompressedLiquid
• Adsorption/PhysicalCarbon fibersCarbon NanotubesMetal organic frameworks (MOFs)
• ChemicalMetal hydrides MH2: Ni, Ti, MnChemical hydrides
• Simple LiH, B2H6 , AlH3• Complex MBH4, M3AlH6
Liquids• Ammonia NH3• Methanol CH3OH• Hydrazine N2H4• Ammoniaborane H3NBH3
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Integration of Hydrogen with renewable electricity
Grid
Electrolyzerelectrochemical
H2 Storage
Power Plant/TurbineThermal
H2 delivery
Wind/Solar farm
Power Plant/TurbineFueling/Chemical
$300/kW $3000/kW
$200-800/kW
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Hybrid Power Plant, Prenzlau, Germany - Enertrag AG
Berliner Zeitung April 2009
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Chemical energy Electrical energy
(1811 – 1896)
The Hydrogen Fuel cell – Equivalence of hydrogen/electricity
2 H2 + O2 2 H2O + electricity
1839Electrolysis
Fuel Cell
Modern Fuel Cell
$100-200 /kW
•2 H2 4 H+ + 4 e- reversible !• Challenge is Oxygen side !
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Electrochemical Hydrogen Conversion with renewable electricity
Grid
Electrolyzerelectrochemical
H2 Storage
Fuel Cellelectrochemical
H2 delivery
Wind/Solar farm
Fueling/Chemical
$300/kW $3000/kW
$200-800/kW
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Utsira, Norway – a (small) hydrogen economy
Nork Hydro 2005
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Utsira, Norway – a (small) hydrogen economy - cont’d
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Key Technical Challenge:Power losses at the Oxygen Evolution (OE) and Reduction (OR) Electrodes
Pow
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Current Density / A/cm-2
Electrolyzer
Power loss due to poor OE/OR catalysts
Poor electrocatalysts cause severe power lossesin fuel cell and electrolyzer mode More basic research on new Materials/Catalysts
O2 + 4H+ + 4e- 2 H2O
2 H2O O2 + 4H+ + 4e-
ηFC = 50-80 %
ηEl = 50-75 %
PElectrolyzer input
PFuel Cell output
Fuel Celle-e-
Water
Pt, Ru, Ir
Oxygen
O2OH
H+
OH2
H2O(l)
OH+
AG StrasserNanostructured electrocatalysts
e.g. Science 4/2009
today
future
in
out
