© OECD/IEA 2010
IEA comments on the draft Solar Energy
Technology Roadmap for South-Africa
CSIR, Pretoria, 18 June 2012
Cédric Philibert
Renewable Energy Division © OECD/IEA 2012
© OECD/IEA 2010
IEA appreciation of the SETRM for SA
More than a good background document
Selects 8 technology areas
Considers market potentials and barriers
Suggests short term actions focusing on R&D needs
The forthcoming « roadmap » or « operational plant » must have other dimensions
Short term and long term (hard or soft) targets
Policy recommendations for implementation
Needs updating
Technologies and thinking evolve quite rapidly!
The IEA is willing to provide constructive comments and promote an integrated approach
© OECD/IEA 2012
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IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
Excellent direct normal (DNI) not always greater than global horizontal irradiance
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Global normal greater than normal direct…
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To be concentrated or not to be…
Concentration allows reducing PV surfaces
And chosing expensive but very efficient materials
But concentration requires tracking the sun…
While tracking does not require concentration
… and neglects the diffuse light
What justifies a preference for CPV > 1 MW?
Cost comparisons must be case by case
A production profile that better matches demand? Possibly, but this benefit arises from tracking the sun, not from concentration!
Tracking for concentration must be quite precise, and this is expensive, esp. 2-axis! Loose 1-axis tracking much cheaper
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If tracking is justified, then concentration might be…
Unless sacrificing direct light is more justified by the even better output profile of CSP due to its built-in thermal storage capabilities!
Tracking changes the profile
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Btw, need to tilt your PV panels?
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Costs have been sharply reduced The PV module learning curve ($/W, logarithmic scales)
Source: Bnef © OECD/IEA 2012
© OECD/IEA 2010
Cost reductions will continue 2020 2030 2050
Typical turnkey system price (2010 USD/kW) 3800 1960 1405 1040
Typical electricity generation costs
(2010 USD/MWH)*
2000 kWh/kW 228 116 79 56 1500 kWh/kW 304 155 106 75 1000 kWh/kW 456 232 159 112
Cost targets for the residential sector
2020 2030 2050 Typical turnkey system price (2010 USD/kW) 3400 1850 1325 980
Typical electricity generation costs
(2010 USD/MWH)*
2000 kWh/kW 204 107 75 54 1500 kWh/kW 272 143 100 72 1000 kWh/kW 408 214 150 108
Cost targets for the commercial sector
2020 2030 2050
Typical turnkey system price (2010 USD/kW) 3120 1390 1100 850
Typical electricity generation costs
(2010 USD/MWH)*
2000 kWh/kW 187 81 62 48 1500 kWh/kW 249 108 83 64 1000 kWh/kW 374 162 125 96
Cost targets for the utility sector
Notes: Based on the following assumptions: interest rate 10%, technical lifetime 25 years (2008), 30 years
(2020), 35 years (2030) and 40 years (2050). Sources: IEA 2010d, Bloomberg New Energy Finance, IEA data.
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Modules now only half system costs
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PV & CSP: peaceful coexistence?
PV and CSP compete on markets (California)
Good time-match between demand and resource reduces the value of storage
CSP more expensive than PV but still justified…
Where peak extends or occurs after sunset
When high-share of PV saturates demand at noon
Depending on round-trip efficiency and costs of storage and grid connection
Flexible CSP with thermal storage may allow for more PV
Saudi Arabia plans, e.g., for 16 GW PV and 25 GW CSP by 2030
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Concentration and efficiencies in STE generation (CSP plants)
Source: Tardieu Alaphilippe, 2007. © OECD/IEA, 2011 © OECD/IEA 2012
© OECD/IEA 2010
IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
Technologies: solar thermal electricity
Key value of STE/CSP is in thermal storage to better match demand More efficient and cheaper than electrical storage
Many different designs and options
Source: Torresol Energy
© OECD/IEA, 2011 © OECD/IEA 2012
© OECD/IEA 2010
Footprints
« Fresnel very compact, troughs more demanding, towers even more… ». True?
Fresnel are compact… but as a result cosine losses are more important than for troughs
reduced output, weak mornings and evenings
Towers can be more or less compact
Depending on the ratio tower height/field size
Footprints should be compared by annual energy (GWh) , not by capacity (MW)
Storage would make comparisons even less relevant
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Comparisons that matter
Comparing plants with similar electric capacities and different storage capabilities is confusing
Does not help appreciate the cost of thermal storage
Better compare plants with similar solar fields and different electric capacities (MW)
The size of the field dictates the yearly output (GWh)
The ratio yearly output on capacity gives the capacity factor (“full load hours”)
The size of storage does not dictate the use
Storage reduces the levelised cost of electricity in some cases but not all
Its role is to increase the value of CSP!
© OECD/IEA 2010
Technologies: solar thermal electricity
Source: ACS Cobra
© OECD/IEA, 2011 © OECD/IEA 2012
Key value of STE/CSP is in thermal storage to better match demand More efficient and cheaper than electrical storage
Many different designs and options
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Possible roles of storage
Thermal storage can be used to shift production, to extend it to base load or to concentrate it to super peak load © OECD/IEA, 2011
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Time-of-use payments are key
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Load curve & merit order with PV
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Load curve & merit order w. CSP
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Stored Heat =∑ mCp ΔT
Large / Smaller ΔT ≈ 278°C/90°C Low Temperature Storage Requires ≈ 3X mass
Stored Heat is Proportional to ΔT
. Tower
566°C
288°C
~378°C
288°C
Low Temperature Storage ~ 3X Cost per MWt
Troughs
Temperatures and storage costs
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DSG and storage: not that easy…
Poor heat transfers from the steam…
3-step storage considered optimal…
Sensible storage for both preheating water and superheating steam
Latent storage for vaporisation
… but not commercial (yet?)
New options developed by BrightSource
De-superheating steam and molten salts
Only for small storage in sub-critical plants
3-tank molten-salt storage for supercritical plants
© OECD/IEA 2012
© OECD/IEA 2010
IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
Back-up/hybridisation
Firming capacities
Increase the solar share in the mix
Walk down the learning curve
Currently in use: Back-up or routine fuel use in PT plants
Steam augmentation in bottoming cycles (ISCC)
Fresnel pre-heating feedwater in coal plants
Options to be developped
Main steam augmentation in efficient coal plants
Hybrid solar-gas with combined cycle
Source: PEGASE/CNRS.
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Hybrid solar-gas…
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Only exist at very small scale
Developing larger air receivers challenging
Steam turbine for combined cycle cannot be atop the tower
Less relevant for South Africa
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Coal-solar add-ons and hybrids
Benefit from the efficiency of modern coal plants
Coal plants have too much high temperature heat
More solar kWh for the buck
Need not to pay for the (whole) turbine, alternator, balance of plant, connecting lines…
Add-ons (on existing plants): mostly fuel savers
Add-ons can boost the power to the extent of the difference between nameplate capacity and gross turbine and alternator capacities – few percent
Hybrid (Greenfield) plants: solar boosts or saves
Fuel saving or booster mode – what the grid needs
Boiler constraints may lead to « booster-saver » hybrid mode
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Hybridisation options for a 1000 MW supercritical coal plant
Hybridization option Preferred solar
collector
Marginal
solar eff.
Max. solar heat
input in MWth
(% of boiler Pth)
Max. Xtra
output
MWe
HP feedwater preheating DSG Fresnel to HX,
HTF PT heating water 45% 350 (16%) 160
LP feedwater preheating Flat plate/evacuated
tubes + Fresnel /PT 18% 350 (16%) 60
Main HP (300 bars) steam
(1)
Molten salts CRS,
DSG CRS? HTF PT? 48%
(45%)
1000 (45%) (2) 480
Reheat steam (60 bars) (1) DSG Fresnel DSG,
DSG CRS 42%
(40%)
250 (11%) 100
Preheating of secondary
combustion air (3)
CRS / Fluidized bed
or volum. receiver 50% 600 (27%) 300
(1) Small efficiency differences with different temperature levels between 450. and 600°C for main steam, 620°C reheat, since there is an excess of high-grade heat in the boiler (2) Engineering issues regarding boiler design may reduce this figure in practice (3) Long-term technological option
Source: Siros, Le Moulec & Philibert, forthcoming © OECD/IEA 2012
© OECD/IEA 2010
Hybridisation options for a 1000 MW supercritical coal plant
Hybridization option Preferred solar
collector
Marginal
solar eff.
Max. solar heat
input in MWth
(% of boiler Pth)
Max. Xtra
output
MWe
HP feedwater preheating DSG Fresnel to HX,
HTF PT heating water 45% 350 (16%) 160
LP feedwater preheating Flat plate/evacuated
tubes + Fresnel /PT 18% 350 (16%) 60
Main HP (300 bars) steam
(1)
Molten salts CRS,
DSG CRS? HTF PT? 48%
(45%)
1000 (45%) (2) 480
Reheat steam (60 bars) (1) DSG Fresnel DSG,
DSG CRS 42%
(40%)
250 (11%) 100
Preheating of secondary
combustion air (3)
CRS / Fluidized bed
or volum. receiver 50% 600 (27%) 300
(1) Small efficiency differences with different temperature levels between 450. and 600°C for main steam, 620°C reheat, since there is an excess of high-grade heat in the boiler (2) Engineering issues regarding boiler design may reduce this figure in practice (3) Long-term technological option
Source: Siros, Le Moulec & Philibert, forthcoming © OECD/IEA 2012
© OECD/IEA 2010
Hybridisation options for a 1000 MW supercritical coal plant
Hybridization option Preferred solar
collector
Marginal
solar eff.
Max. solar heat
input in MWth
(% of boiler Pth)
Max. Xtra
output
MWe
HP feedwater preheating DSG Fresnel to HX,
HTF PT heating water 45% 350 (16%) 160
LP feedwater preheating Flat plate/evacuated
tubes + Fresnel /PT 18% 350 (16%) 60
Main HP (300 bars) steam
(1)
Molten salts CRS,
DSG CRS? HTF PT? 48%
(45%)
1000 (45%) (2) 480
Reheat steam (60 bars) (1) DSG Fresnel DSG,
DSG CRS 42%
(40%)
250 (11%) 100
Preheating of secondary
combustion air (3)
CRS / Fluidized bed
or volum. receiver 50% 600 (27%) 300
(1) Small efficiency differences with different temperature levels between 450. and 600°C for main steam, 620°C reheat, since there is an excess of high-grade heat in the boiler (2) Engineering issues regarding boiler design may reduce this figure in practice (3) Long-term technological option
Source: Siros, Le Moulec & Philibert, forthcoming © OECD/IEA 2012
© OECD/IEA 2010
Hybridisation options for a 1000 MW supercritical coal plant
Hybridization option Preferred solar
collector
Marginal
solar eff.
Max. solar heat
input in MWth
(% of boiler Pth)
Max. Xtra
output
MWe
HP feedwater preheating DSG Fresnel to HX,
HTF PT heating water 45% 350 (16%) 160
LP feedwater preheating Flat plate/evacuated
tubes + Fresnel /PT 18% 350 (16%) 60
Main HP (300 bars) steam
(1)
Molten salts CRS,
DSG CRS? HTF PT? 48%
(45%)
1000 (45%) (2) 480
Reheat steam (60 bars) (1) DSG Fresnel DSG,
DSG CRS 42%
(40%)
250 (11%) 100
Preheating of secondary
combustion air (3)
CRS / Fluidized bed
or volum. receiver 50% 600 (27%) 300
(1) Small efficiency differences with different temperature levels between 450. and 600°C for main steam, 620°C reheat, since there is an excess of high-grade heat in the boiler (2) Engineering issues regarding boiler design may reduce this figure in practice (3) Long-term technological option
Source: Siros, Le Moulec & Philibert, forthcoming © OECD/IEA 2012
© OECD/IEA 2010
Hybridisation options for a 1000 MW supercritical coal plant
Hybridization option Preferred solar
collector
Marginal
solar eff.
Max. solar heat
input in MWth
(% of boiler Pth)
Max. Xtra
output
MWe
HP feedwater preheating DSG Fresnel to HX,
HTF PT heating water 45% 350 (16%) 160
LP feedwater preheating Flat plate/evacuated
tubes + Fresnel /PT 18% 350 (16%) 60
Main HP (300 bars) steam
(1)
Molten salts CRS,
DSG CRS? HTF PT? 48%
(45%)
1000 (45%) (2) 480
Reheat steam (60 bars) (1) DSG Fresnel DSG,
DSG CRS 42%
(40%)
250 (11%) 100
Preheating of secondary
combustion air (3)
CRS / Fluidized bed
or volum. receiver 50% 600 (27%) 300
(1) Small efficiency differences with different temperature levels between 450. and 600°C for main steam, 620°C reheat, since there is an excess of high-grade heat in the boiler (2) Engineering issues regarding boiler design may reduce this figure in practice (3) Long-term technological option
Source: Siros, Le Moulec & Philibert, forthcoming © OECD/IEA 2012
© OECD/IEA 2010
Non-concentrating solar thermal power?
Solar ponds have very low efficiency
Evacuated tubes/CPC collectors best prospects
Using organic rankine cycles
But more likely in hybridisation with coal plants
Solar chimneys (“updraft towers”)
Not being developed as stand-alone devices…
Experimental non-
concentrating solar
thermal electricity
near Nice (France).
Source: SAED
© OECD/IEA 2012
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Solar chimneys?
Costs of receivers deemed too high
As benefits grow with the square of the size, difficult to justify small-scale
demonstration
But… solar chimneys could be considered for dry-cooling of CSP plants
A development of the known Heller scheme
Natural Draft Cooling Towers at the Shahid Rajai
TPP (4 x 250 Mwe), Iran
© OECD/IEA 2012
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IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
Solar water heating is a must
Source: W. Weiss
SWH recently installed in South Africa
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Hot water in Saudi Arabia
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Solar cooling
Some large installations, but costs are often too high compared with “conventional” cooling devices run by (solar) electricity (centralised or decentralised)
Air-conditioning daytime peak loads help make PV competitive
Reversible ground-source heat pumps to respond to both cooling and heating demand with renewable electricity?
© O
ECD
/IEA
, 20
11
Resource and demand match well
Thermally-driven cooling?
Cooling is ultimately work, not “heat”…
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Solar heat for industry & services
Large heat needs at various temperature levels in industry and services; low-temp. solar heat available everywhere, demand all year round
High-temp. solar heat under hot and dry climates
Estimated industrial heat demand by temperature range in Europe, 2003
Sou
rce: Wern
er, 20
05
-20
06
PJ
© OECD/IEA 2012
© OECD/IEA 2010
Source: AEE INTEC. Source: Deepak Gadhia
Solar water heaters in a service area (Austria) Cooking with Scheffler dishes (India)
Source: SolarWall.
Solar air drying of coffee beans (Columbia) Experimental mid-size industrial solar oven (France)
Source: Four Solaire Développement. © OECD/IEA 2012
© OECD/IEA 2010
Solar heat reaches competitiveness
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Price of low-temperature solar heat for heating networks and large industrial systems
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CSP and desalination: no big gain
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Co-generation from CSP: an example from Morocco Oriental?
Electricity demand is maximum and summer; output from CSP plants maximum in Spring
Except for specific circumstances (large hydro, possibly with pump-back scheme), storage over several months way too costly
However… demand of high-temperature process heat for sugar refineries is maximum in May, June and July…
Excess or all solar steam could be used for sugar in three months, and electricity generated in the rest of the year…
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Scheffler dishes: steam for services
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Small experimental solar furnace
Mont-Louis,
French pyrenees
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Pottery cooking in the solar furnace
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Melting metals in the solar furnace
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Large industrial furnace (1 MWth)
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Odeillo, French pyrenees
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Direct gasification of biomass… or coal?
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Solar fuels for inter-seasonal storage
CSP has excess power in Spring, lacks in winter
Storing hydrogen is not easy, consumes energy
Liquid fuels, but ammonia, have carbon atoms
One option could be to store reduced metals as means to generate hydrogen at will
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Many uses for industrial heat & fuels
SETRM for SA notes the possibility of melting scrap aluminum
Solar heat in coal-to-liquid manufacturing
Would bring life-cycle emissions down, close to those of oil products
Sasol plant in RSA the largest CO2 point-source in the world
Full inventory of options by temperature levels should be made
© OECD/IEA 2010
IEA suggestions
1. From a resource analysis (re-) consider the concentrating/non-concentrating trade-offs
For various PV technologies and PV vs. CSP
2. Appraise the role of storage in the context of RSA’s grid needs
3. Consider solar-coal hybridisation
4. Look at all options for process heat
5. Consider the global context for manufacturing
© OECD/IEA 2012
© OECD/IEA 2010
PV: Where do we stand?
Capacities added in 2011: 27.5 GW
Cumulative: 67.5 GW
6 markets >1 GW
46% of newbuilt capacities in Europe
0
10
20
30
40
50
60
70
80
2005 2006 2007 2008 2009 2010 2011
GW
RoW
China
US
Spain
Japan
Italy
Germany
© OECD/IEA 2010
Competitive markets emerge
Grid parity in Germany, Italy, Mexico…
Newbuilt systems in Germany: no more than 80 to 90% of power benefitting from FITs
Net metering: Italy, Brazil, Denmark, Spain…
Compétitiveness with power from oil:
Islands, Middle East, Japan, Italy…
Favourable where demand peaks at hot mid-days
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Twin market changes
From European to global markets
From subsidised to (partly-) competitive markets
Will eventually more than offset recent FIT cuts
Global manufacturing capacity over 50 GW/a
2012 and 2013 difficult for companies…
And analysts: short term market assessment difficult!
May not be the good timing for developing PV cell and module manufacturing capacities
Significant share of value is local anyway
Prospects for manufacturing thermal collectors and CSP materials significantly greater, esp. Fresnel and solar towers
© OECD/IEA 2010
An integrated approach should…
Distinguish the needs for heat and work
At the various temperature pressure levels
Looking for possible complementarities
Consider variations in time at all scales
Aim at having energy prices reflect costs
In real time and place, as much as possible
Consider the trade-offs between decentralised and centralised electricity generation (and storage), taking grid costs into account
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Growth of PV by2035 in the WEO scenarios
Scenario New Policies 450 450 delayed-CCS
Capacities 2035 499 GW 901 GW 1030 GW
Annual market 22.1 GW 38.5 GW 43.7 GW
2 0 1 0
ENERGY
TECHNOLOGY
PERSPECTIVES
Scenarios &
Strategies
to 2050
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Controlling the volumes with FiT level appears difficult