-
Sustainable energy storage in chemical fuels for CO2 neutral energy generation:
a plasma perspective
Richard van de Sanden
Dutch Institute for Fundamental Energy Research, P.O.Box 1207, 3430 BE Nieuwegein, The Netherlands
Conférence de l’Institut Coriolis pour l’Environnement de l’École Polytechnique 2013
-
The TeraWatt Challenge (15 TW)
see also :
M.I. Hoffert et al. Nature 385, 881 (1998)
R.E. Smalley, MRS Bulletin 30 412 (2005)
-
Year
Population
Energy
Wor
ld p
opul
atio
n (B
illio
n)
2
4
10
2000 1500 1000 500 0 0
2500 3000
6
8
2013
Oil
Burning fossil fuels
CO2!
-
The Terawatt challenge
2
4
6
8
2000 2010 2020 2030 2040
200
400
600
800
1000
Pr
im. E
nerg
y Co
nsum
ptio
n[Q
uadr
ill. B
tu]
World Population [Billion]
U.S.. Energy Information Agency Annual Energy Outlook 2011
DOE/EIA-0383(2011)
Non-O
ECD
OEC
D
-
The Terawatt challenge
10
20
30
40
2000 2010 2020 2030 2040
200
400
600
800
1000
Pr
im. E
nerg
y Co
nsum
ptio
n[Q
uadr
ill. B
tu]
World CO
2 Emission [G
t]
U.S.. Energy Information Agency Annual Energy Outlook 2011
DOE/EIA-0383(2011)
Non-O
ECD
OEC
D
-
The TeraWatt Challenge
see also :
M.I. Hoffert et al. Nature 385, 881 (1998)
R.E. Smalley, MRS Bulletin 30 412 (2005)
Sustainable, CO2 neutral, energy infrastructure essential
-
Contents
The TeraWatt Challenge: CO2 neutral energy supply Sustainable Energy Generation Storage and Transport of Energy: Solar Fuels
Solar Fuels from CO2 and H2O: conversion processes
Water splitting CO2 activation Plasma activation of CO2
Conclusions and Outlook
-
Sustainable energy - is there enough?
More sustainable energy than global energy demand
The big sources: solar wind biomass
geothermal ocean/wave hydro
-
Sustainable energy – future
• ITER: 2020 first plasma
• Commercial: 2040 ?
• Transport: need for fuels (air transport)
-
Solar power generation: DoE Sunshot
-
Price-experience curve of silicon PV modules (combined effects of innovation, experience and scale)
Solar power generation: Economy of scale
Grid parity ~1 €/Wp
Clear economy of scale
-
Grid parity in Europe
From 2020 a significant fraction is sustainable !
2025
-
However…….
Sustainable power generation is booming but it is
with time-scales ranging from minutes to months
Mismatch between supply and demand
German solar and wind energy
Solution: Energy storage
inhomogeneous and intermittent
-
Sustainable energy - storage needed
water reservoirs
chemical batteries
stored heat
Artificial chemical fuel
Storing energy: mechanical electrical electro-chemical chemical
-
Storing and Transport of Energy
Presently: 85% of the global energy is transported by fuels
Carbon containing fuels (hydrocarbons, alcohols, etc.) generated from CO2 and H2O to store sustainable energy:
Solar Fuels
-
Solar Fuels
• Large potential to contribute to a CO2 neutral energy infrastructure
• Storage and transport of sustainable energy in chemical bonds: close to present infrastructure
• Large efforts world wide on Solar Fuels:
-
Solar Fuels
• Large potential to contribute to a CO2 neutral energy infrastructure
• Storage and transport of sustainable energy in chemical bonds: close to present infrastructure
• Large efforts world wide on Solar Fuels:
Basically splitting H2O or activating CO2 using direct solar (heat & light) or sustainably
generated electrical energy
End product carbon containing fuels:
Solar Fuels
-
Fuel processing from H2O
Basically production of H2 : By splitting H2O: 1) H2O H2 + ½ O2
H2 production main activity globally
Hyundai i35 first commercial car on H2 + fuel cell
-
Fuel processing from H2O or CO2
Basically production of H2 or CO : By splitting H2O: 1) H2O H2 + ½ O2
or activating CO2: 1) CO2 CO + ½ O2
Cars fueled by wood or coal gas during WWII
-
Fuel processing from CO2 and H2O: syngas
Production of syngas H2 and CO : By splitting H2O: 1) H2O H2 + ½ O2
2) followed by a reverse watershift reaction
H2 + CO2 H2O + CO (endothermic) or activating CO2: 1) CO2 CO + ½ O2
2) followed by a watershift reaction
CO + H2O CO2 + H2 (exothermic)
Syngas: by means of Fisher-Tropsch process carbon containing fuels
-
FT=Fischer-Tropsch reaction (R)WGS=(reverse) watergas shift
H2
Captured CO2
CO2
WGS
RWGS Air Solar energy conversion: H2 O H2 + ½O2 CO2 CO + ½O2
CO2 Hydrogenation
Methane Methanol
CO FT Fuel
H2
CO
water
Solar Fuels
Courtesy Wim Haije (ECN)
-
Gas-to-liquid from syngas: Fisher-Tropsch
Shell Qatari plant (2009) Methane reformation: CH4 + H2O CO + 3H2 C-fuels Investment of 19 B$; Revenue 4 B$/yr Large scale proven
Ref. Bloomberg
However still based on fossil fuels
-
Gas (or fossil)
Plant
Sun or Wind Energy Plant
Sun
Electricity grid
Gas grid
Fossil
Wind
Water Liquid fuels or raw materials for industry
Gas buffer Fossil
current infrastructure of energy system
Current Energy generation infrastructure
-
Gas (or fossil)
Plant
Sun or Wind Energy Plant
CO2 Solar Fuel Plant
Sun
Electricity grid
Gas grid
Fossil
Wind
Water Liquid fuels or raw materials for industry
Gas buffer Fossil
Direct
Indirect
Solar Fuels Production from CO2 and H2O using sustainable energy fitted in our current infrastructure
Towards the Renewable Energy infrastructure
-
Gas Plant
Sun or Wind Energy Plant
CO2 Solar Fuel Plant
Sun
Electricity grid
Gas grid
Wind
Water Liquid fuels or raw materials for industry
Gas buffer
Direct
Indirect
Solar Fuels Production from CO2 and H2O as storage using intermittent sustainable energy
Full Sustainable Energy Infrastructure
-
Contents
The TeraWatt Challenge: CO2 neutral energy supply Sustainable Energy Generation Storage and Transport of Energy: Solar Fuels
Solar Fuels from CO2 and H2O: conversion processes
Water splitting CO2 activation Plasma activation of CO2
Conclusions and Outlook
-
FT=Fischer-Tropsch reaction (R)WGS=(reverse) watergas shift
H2
Captured CO2
CO2
WGS
RWGS Air Solar energy conversion: H2 O H2 + ½O2 CO2 CO + ½O2
CO2 Hydrogenation
Methane Methanol
CO FT Fuel
H2
CO
water
Solar Fuels
Courtesy Wim Haije (ECN)
-
Biomass (< 1%)
Photosynthetic Micro organism (> 5%)
Man-made, articifical
(modified) natural, living
Solar
European Science Foundation, Science Policy Briefing 34 (Sept. 2008)
Primary and secondary
biofuels
Courtesy Wim Sinke (ECN)
Solar energy conversion (direct & indirect)
-
Biomass (< 1%)
Photosynthetic Micro organism (> 5%)
Man-made, articifical
(modified) natural, living
Thermochemical Conversion (> 5%)
Solar
European Science Foundation, Science Policy Briefing 34 (Sept. 2008)
Primary and secondary
biofuels
Courtesy Wim Sinke (ECN)
Solar energy conversion (direct & indirect)
-
Concentrated solar power (CSP)
CeO2 + sunlight CeO2-x + 1/2x O2 CO2 + CeO2-x CO + CeO2 Or based on ZnO, Fe3O4
Steinfeld group (ETH Zurich), Science 330 1798 (2010)
Thermochemical using CSP (direct)
Cyclic, solar to CO efficiency: 3-4% Nanostructured materials + catalysis essential
-
Solar energy conversion (direct & indirect)
Biomass (< 1%)
Photosynthetic Micro organism (> 5%)
Photocatalytic Nanodevices (> 5%)
Man-made, articifical
(modified) natural, living
Thermochemical Conversion (> 5%)
Solar
European Science Foundation, Science Policy Briefing 34 (Sept. 2008)
Primary and secondary
biofuels
Courtesy Wim Sinke (ECN)
-
Direct photocatalytic conversion of H2O
Which approach is most promising ?
The challenge
Nanostructured materials and catalysis essential
But also photon management: plasmonics, etc.
Courtesy Roel van de Krol (HZ Berlin)
-
Different anorganic materials
Direct sunlight into hydrogen 1-3%
2H2O 2H2 + O2
Science 331 746 (2011)
Photocatalytical splitting of water
Nanostructured materials and catalysis essential
Graetzel, Nature, 414, 15 Nov. (2001) 338.
-
Water splitting
Courtesy Kevin Sivula
Photo-electrochemical cells: generation of solar H2
-
For large scale deployment:
Elements of hope
2H2O 2H2 + O2
Watersplitting using electrochemical cell
Nocera group (MIT): basically tandem a-Si solar cell with Co based catalyst
-
Direct photocatalytic conversion of CO2
Roy, Varghese, Paulose, Grimes, ACSNano 4, 1260 (2010)
η = 0.0148%
To tailor the catalyst to optimally use the solar spectrum for activating the
catalyst
The challenge
CO2 + 2H2O CH4 + 2O2
Nanostructured materials and catalysis essential
Difficult to activate CO2
by photocatalysis
-
Solar energy conversion (direct & indirect)
Biomass (< 1%)
Photosynthetic Micro organism (> 5%)
Photocatalytic Nanodevices (> 5%)
Man-made, articifical
(modified) natural, living
Thermochemical Conversion (> 5%)
Solar
PV conversion + Electrolysis (> 20%)
European Science Foundation, Science Policy Briefing 34 (Sept. 2008)
Primary and secondary
biofuels
Courtesy Wim Sinke (ECN)
-
2H2O 2H2 + O2
Efficiency >> 20 %
Watersplitting using PV & electrolyser
Efficiency 70-80 %
Advantage: separate optimization possible Current bottleneck: use of scarce materials (a.o. Pt)
sustainable energy
*H2 generation from steam reformation
-
2H2O 2H2 + O2
Efficiency >> 20 %
Watersplitting using PV & electrolyser
Efficiency 70-80 %
Advantage: separate optimization possible Current bottleneck: use of scarce materials (a.o. Pt)
sustainable energy
> 8 €/kg* >16 €/kmol
*H2 generation from steam reformation
-
Electric energy conversion: electrolysis
Electrochemical Conversion
K.P. Kuhl et al., Energy Environ. Sci. 5 7050 (2012)
Electrical energy to CO > 10%
-
Electric energy conversion: electrolysis
Electrochemical Conversion
K.P. Kuhl et al., Energy Environ. Sci. 5 7050 (2012)
Electrical energy to CO > 10%
Difficult to activate CO2
due to solubility
-
Contents
The TeraWatt Challenge: CO2 neutral energy supply Sustainable Energy Generation Storage and Transport of Energy: Solar Fuels
Solar Fuels from CO2 and H2O: conversion processes
Water splitting CO2 activation Plasma activation of CO2
Conclusions and Outlook
-
Solar energy conversion (direct & indirect)
Biomass (< 1%)
Photosynthetic Micro organism (> 5%)
Photocatalytic Nanodevices (> 5%)
Man-made, articifical
(modified) natural, living
Thermochemical Conversion (> 5%)
Solar
PV conversion + Electrolysis (> 20%)
Solar to electricity + Plasma conversion
European Science Foundation, Science Policy Briefing 34 (Sept. 2008)
Primary and secondary
biofuels
Solar Fuels
Courtesy Wim Sinke (ECN)
-
FT=Fischer-Tropsch reaction (R)WGS=(reverse) watergas shift
H2
Captured CO2
CO2
WGS
RWGS Air
CO2 Hydrogenation
Methane Methanol
CO FT Fuel
H2
CO
water
Solar Fuels
Courtesy Wim Haije (ECN)
Conversion: • Electrocatalysis • Photocatalysis • Thermocatalysis • Plasma activation
Direct plasma activation of CO2
-
Plasmachemical activation of CO2
Plasma-chemical Conversion
Energy efficiency: ~ 41%
Why plasma?
• Higher energy density medium
• Exploit the nonequilibrium??
Concentrating the energy input on degrees of freedom which are essential for CO2
dissociation!!
Thermodynamics
Alex Fridman (Drexel Univ., US)
-
What is plasma?
Gaseous medium composed of :
Atoms
Molecules
Radicals
Ions (negative, positive)
Electrons
All possibly in the excited state (internal energy!)
Nonequilibrium medium nonequilibrium distributions
(non-Maxwellian, non-Boltzmann)
p
T
Telectron
Tgas
1 eV
1 atm
*1 eV = 11600 K
Used abundantly in e.g. materials processing
-
Electric energy conversion: plasmachemical
Plasmachemical Conversion
Energy efficiency: ~ 41%
Thermodynamics Why plasma?
• Higher energy density medium
• Exploit the nonequilibrium??
• No use of scarce materials: free electrons and electric field do the job
• Large scale possible (15 TW !!)
-
Plasmas and large scale
Acetylene production from coke and natural gas in Hüls arc reactor
H2 and carbon black production from coke and natural gas thermal arc reactors
But also note that many large scale industries heavily depend on plasma technology: IC, display, coatings, solar, etc.
Hüls reactor
-
Energy efficient dissociation using plasma?
Can it be done energy efficiently?
Cost of plasmas expensive energy-wise: • Creating electron-ion pair typically > 30 eV !*
*1 eV = 100 kJ/mol
ionization
electrons
electric field
collisions
-
Energy efficient CO2 dissociation with plasma?
Can it be done energy efficiently?
Cost of plasmas expensive energy-wise: • Creating electron-ion pair typically > 30 eV !*
• Dissociation energy CO2 5.5 eV, but more is needed to get dissociation by direct electron impact (dissociative branch)
If electrons must do the job directly: no energy efficient dissociation possible !!
CO2 potential
-
1000
2000
3000
Vib.
Ene
rgy
[cm
-1]
ν2
ν1 ν3
Optimal vibrational state CO2 dissociation
(4.26 µm: IR)
Rusanov et al. Usp. Fiz. Nauk. 134 185 (1981)
ν2
electrons
electric field
collisions
vibrational excitation
Can we controle this?
-
Electron energy loss in CO2 plasma
Rusanov et al. Usp. Fiz. Nauk. 134 185 (1981)
electrons
electric field
collisions
vibrational excitation
Electron energy loss depends on reduced electric
field depends on average electron energy
-
V-V exchange and VT relaxation
Rusanov et al. Usp. Fiz. Nauk. 134 185 (1981)
electrons
electric field
collisions
vibrational excitation
V-V relaxation much faster than V-T relaxation for low v number: leads to Tvib > Tgas
-
Nonequilibrium effects: Treanor distribution
Rusanov et al. Usp. Fiz. Nauk. 134 185 (1981)
electrons
electric field
collisions
vibrational excitation
Telectron > Tvib > Tgas
Treanor–like distribution: overpopulation of higher vibrational
states leads to lower activation energies, faster kinetics
-
Energy efficient dissociation using plasma?
Can it be done energy efficiently?
electrons
electric field
collisions
radical
chemistry
Cost of plasmas expensive energy-wise: • Creating electron-ion pair typically > 30 eV !
• Additionally use radical O (!) CO2 CO + O (ΔH=5.5 eV) followed by CO2 + O CO+ O2 (ΔH=0.3 eV) so overall CO2 CO + ½O2 (ΔH=2.9 eV)
A.V. Eletskii, B.M. Smirnov, Pure. Appl. Chem. 57 1235 (1985)
-
Energy efficient dissociation of CO2
Can it be done energy efficiently?
Yes if the following plasma aspects are considered:
• Create nonequilibrium plasma with Telectron > Tvib> Tgas
• Low mean electron energy (1-2 eV) to excite dominantly lower
vibrational states and sufficient ionization degree (>10-5): Vibrational pumping (nonequilibrium effect!) and low V-T relaxation takes
care of high population of vibrational states required for efficient dissociation and fast kinetics
• Re-use atomic oxygen to dissociate aditionally CO from CO2 (high p, low conversion!)
-
Energy efficient dissociation of CO2
Can it be done energy efficiently?
Yes if the following plasma aspects are considered:
• Create nonequilibrium plasma with Telectron > Tvib> Tgas
• Low mean electron energy (1-2 eV) to excite dominantly lower
vibrational states and sufficient ionization degree (>10-5): Vibrational pumping (nonequilibrium effect!) and low V-T relaxation takes
care of high population of vibrational states required for efficient dissociation and fast kinetics
• Re-use atomic oxygen to dissociate aditionally CO from CO2 (high p, low conversion!)
Engineering specs to choose plasma:
• Use kinetics, time scales of relaxation
• Design electric field configuration
• High pressure to minimize wall losses
-
DBD/Packed bed Catalytic reaction enhanced by Plasma catalysis. http://www.jeh-
center.org/electro/plasma/theory.html
Corona discharge
http://www.pages.drexel.edu/~rpg32/Research.htm
Dielectric barrier discharge
Gliding arc
Surface discharge
• Non-thermal process (room temp) • Throughput necessary (scale !) • Scalable (stacked microreactors?) • Essentially nonequilibrium • Controle of EEDF
Courtesy Tomohiro Nozaki (Tokyo Institute of Technology)
1-5mm
Choice of plasma
Microwave discharge
-
Sub-atmospheric CO2 plasmas: CO2 CO + ½O2
(Sub-)atmospheric μwave discharge
-
Various nozzle positions/types explored
Nozzle Positions I z = -3 cm II z = 0 cm III z = 12.4 + 0 cm IV z = 12.4 + 5 cm V z = 12.4 + 3 cm
4 3
2 1
Cavity (12.4 cm)
IV I II III V z
Nozzle configurations/types: 1. Straight (∅ 26 mm) 2. Symmetric (∅ 26 mm: ∅5 mm & ∅10 mm throat) 3. Laval (∅ 26 mm: ∅5 mm throat) 4. Double nozzle (Laval/Cu exit nozzle of ∅5 mm)
1 2
3 4
915 MHz E010 or TM010 mode @ 3kW: Emax = 27 kV/m
Engineering knobs to controle plasma generation to obtian high power efficiency
of CO2 activation
-
0
10
20
30
40
50
60
70
80
0 2000 4000 6000 8000
Out
put f
low
[slm
]
Power [W]
Experimental Results: supersonic region
CO produced at expense of CO2 CO2 CO + ½O2 ∆H = 2.9 eV
Constant CO2 flow of 75 SLM
η = ∆H/ECO
Energy efficiency:
10 mm symmetric nozzle at exit of RF cavity RF input power 3020-8010 W Gas pressure reaction chamber 190-250 mbar Expansion chamber 0.3..0.4 mbar Energy spent per CO2 molecule 0.56..1.49 eV
CO2
CO O2
-
0
10
20
30
40
50
60
70
0 2000 4000 6000 8000
Effic
ency
[%]
Power [W]
Energy efficiency [%]
Conversion efficiency [%]
0
10
20
30
40
50
60
70
80
0 2000 4000 6000 8000
Out
put f
low
[slm
]
Power [W]
Experimental Results: supersonic region
CO produced at expense of CO2 CO2 CO + ½O2
Constant CO2 flow of 75 SLM
η = ∆H/ECO
CO2
CO
O2
ηpower
βdiss
-
0
10
20
30
40
50
60
70
0 2000 4000 6000 8000
Effic
ency
[%]
Power [W]
Energy efficiency [%]
Conversion efficiency [%]
0
10
20
30
40
50
60
70
80
0 2000 4000 6000 8000
Out
put f
low
[slm
]
Power [W]
Experimental Results: supersonic region
CO produced at expense of CO2 CO2 CO + ½O2
Constant CO2 flow of 75 SLM
η = ∆H/ECO
CO2
CO
O2
ηpower
βdiss
Power efficiency ≈ 60% Dissociation (@3.6kW) ≈ 11%
-
η = ΔH/ECO CO2 CO + ½O2 ΔH = 2.9 eV
From A. Fridman, “Plasma Chemistry” (Taylor&Francis 2009)
Literature reports > 50% energy efficiency of CO2
dissociation !
Key is reduced electric field and energy per molecule!
Energy efficiency
Reported results on energy efficiency
-
CO2 CO + ½O2
Efficiency > 20 %
CO2 activation using plasma
Efficiency 70-80 %
Advantage: separate optimization possible
sustainable energy
*compare with electrolysis H2O > 16 €/kmol
-
CO2 CO + ½O2
Efficiency > 20 %
CO2 activation using plasma
Efficiency 70-80 %
Advantage: separate optimization possible
sustainable energy
97 kWh/kmol* @ ηpower =80%
*compare with electrolysis H2O > 16 €/kmol
-
Conclusions and Outlook
Sustainable energy generation within reach : Clear economy of scale, hugh capacity deployed
Next challenge: storing sustainable energy in solar fuels Cost effective CO2 neutral energy infrastructure In line with the present energy infrastructure Several approaches are adopted: H2O splitting prominent, CO2
activation still in infancy phase, direct and indirect
Plasma activation of CO2 approach highlighted: Nonequilibrium essential to obtain high energy efficiency Power efficiency obtained so far ~ 60% ; 80% within reach Next challenge: - diagnose the plasma (E/ngas, CO2(r,v), ne, etc.) - gas stream separation without energy penalty
-
Directing Matter and Energy “Five challenges for science and the imagination”, Report Basic Energy Science Advisory Committee
How do we characterize and control matter away, especially very far away, from equilibrium?
Nonequilibrium: controlling complexity
One of the five challenges directly linked with plasma science:
-
Ackowledgements
FOM-DIFFER (Solar Fuels) Waldo Bongers Adelbert Goede Martijn Pieter-Willem Groen Institute fur Plasmaforschung Jochen Kopecki
Martina Leins
Andreas Schulz
Matthias Walker
FOM-DIFFER (Fusion) Tony Donne et al. Greg De Temmerman et al.
TU/e Richard Engeln
Stefan Welzel
Srinath Ponduri
Florian Brehmer
Ma Ming
Sustainable energy storage in chemical fuels for CO2 neutral energy generation: �a plasma perspective���Richard van de Sanden�The TeraWatt Challenge (15 TW)Slide Number 3The Terawatt challengeThe Terawatt challengeThe TeraWatt ChallengeContentsSustainable energy - is there enough?Slide Number 9Slide Number 10Slide Number 11Slide Number 12However…….Sustainable energy - storage neededSlide Number 15Solar FuelsSolar FuelsSlide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25ContentsSlide Number 27Solar energy conversion (direct & indirect)Slide Number 29Slide Number 30Solar energy conversion (direct & indirect)Direct photocatalytic conversion of H2OSlide Number 33Slide Number 34Slide Number 35Direct photocatalytic conversion of CO2Solar energy conversion (direct & indirect)Slide Number 38Slide Number 39Electric energy conversion: electrolysisElectric energy conversion: electrolysisContentsSolar energy conversion (direct & indirect)Slide Number 44Plasmachemical activation of CO2What is plasma?Electric energy conversion: plasmachemicalPlasmas and large scale Energy efficient dissociation using plasma?Energy efficient CO2 dissociation with plasma?Slide Number 51Slide Number 55Slide Number 56Slide Number 59Energy efficient dissociation using plasma?Energy efficient dissociation of CO2Energy efficient dissociation of CO2Choice of plasma(Sub-)atmospheric μwave discharge Various nozzle positions/types exploredSlide Number 66Slide Number 67Slide Number 68Slide Number 69Slide Number 70Slide Number 71Conclusions and OutlookSlide Number 73Ackowledgements