Concentrating Solar Power Its potential contribution to a sustainable energy future
Robert Pitz-Paal, DLR, Institute of Solar Research
Chairman of EASAC Working Group
Tuesday , October 9th, 2012 Pretoria, South Africa
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Working Group Membership
• Professor Amr Amin, Helwan University, Egypt • Professor Marc Bettzüge, Cologne University, Germany • Professor Philip Eames, Loughborough University, UK • Dr. Gilles Flamant, CNRS, France • Dr Fabrizio Fabrizi, ENEA, Italy • Professor Avi Kribus, Tel Aviv University, Israel • Professor Harry van der Laan, Universities of Leiden and Utrecht, Netherlands • Professor Cayetano Lopez Martinez, CIEMAT, Spain • Professor Fransisco Garcia Novo, University of Seville, Spain • Professor Panos Papagiannakopoulos, University of Crete, Greece • Mr Erik Pihl, Chalmers University of Technology, Sweden • Professor Robert Pitz-Paal (Chair), DLR, Germany • Mr Paul Smith, University College Dublin, Ireland • Professor Hermann-Josef Wagner, Ruhr-Universitat Bochum, Germany
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Key Questions
• What is Concentrating Solar Power (CSP)?
• The Value of CSP Electricity
• Today’s Markets and Costs
• Cost Reduction Potential
• Potential Role of CSP Technology South Africa
• Challenges
• Recommendations
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Conventional power plants
What is CSP ?
5
Solar thermal power plants
What is CSP ?
What is CSP?
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Technology
Peak solar to
electricity
conversion
efficiency
Annual solar-to-
electricity
efficiency
Water consumption,
for wet/dry cooling
(m3/MWh)
Land use
(m²/MWh/a)
Parabolic troughs 23-27% 15-16% 3-4 / 0.2 6-8
Linear Fresnel
systems 18-22% 8-10% 3-4 / 0.2 4-6
Towers (central
receiver systems) 20-27% 15-22% 3-4 / 0.2 8-12
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Market Situation
Ground Requirements
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Thermal Storage vs. Electric Storage
CSP with storage and fossil hybridisation can provide all 3 components of value Thermal storage economically favorable
2000 h
+2000 h
>95 %
= 75%
200 h
Firm mid
load
capacity
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Stromgestehungskosten CSP mit und ohne therm. Speicher
Electricity generation cost as function of solar multiple and storage size
(parabolic trough plant
type SEGS VIII,
Pel, = 80 MWel
yearly DNI = 2500
kWh/m²
Sm for 21. March!)
solar multiple (sm)
storage 12 h rated power
no storage
0.1
E
uro
/kW
h
0.1
5
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Design Options for CSP with Thermal Storage
Source: IEA CSP Technlogy Roadmap 2010
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Hybridisation secures firm capacity
Hybridsierung im Kraftwerk statt externe Schattenkapazität
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Today‘s markets: parabolic trough is most mature technology
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Parabolrinne mit thermischem Speicher
15
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Status 2012 In Operation: 1.9 GW Under Construction: 3.0 GW Under development: 3.3 GW In operation until 2020 (estim.) 23.4 GW
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Today‘s markets: New concepts (Tower/Fresnel) target for faster cost reduction
Higher Concentration lead
to higher system efficiency
Tower
c 800-1000
T 800°C
PEAK 28-30%
LEC: 11-7 €ct/kWh
(2010/2020)*
* NREL study „Current and Future cost....“, 2010
Trough
c < 100
T 400°C (-500°)
PEAK 25-27%
LEC: 13-8 €ct/kWh
(2010/2020)*
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Ivenpah Solartower Project
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Technology LEC €c / kWh
CSP: 100 MW w/o storage (Arizona) 17.9 (~14,5 in 2012)
Pulverized coal: 650 MW: base-load 6.9
Pulverized coal: 650 MW: mid-load 9.0
Gas combined cycle mid-load 6.1
Wind onshore: 100MW 8.5
Wind offshore: 400 MW 15.3
Photovoltaic: 150 MW (Arizona): 21.2 (~12 in 2012)
Calculation based on Data form US Department of Energy 2010, (Currency conversion 2010 $/€ = 0.755)
2010 levelized cost of electricity
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The Value of CSP Electricity
Components of value:
1. kWh’s of electrical energy
2. Contribution to meeting peak capacity needs
3. ‘Services’ to support grid operation
Conclusions:
– Must evaluate at system level
– Value of storage increases as more variable renewables on system
– All 3 components of value can be significant
– Subsidy schemes need to reflect the price signals from competitive electricity markets
– Auxiliary firing as transition technology
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How to reduce costs?
Estimates based on detailed engineering studies • Mass production and scaling (25 - 30%) • Technology improvements (20 - 30 % )
Breakthroughs in – Front Surface Reflectors (Lifetime) – Heat Transfer Fluids for higher temperature (Stability and costs) – Advanced Solar Power Cycles (Solarized Design) – Storage Systems (Adaptation to Temperature and Heat Transfer Fluid)
LEC < 9 €cents/kWh realistic based on technology concepts already realized in lab-scale today
Rate of cost reduction depends on learning rate and growth rates. The
authors estimate cost breakeven with fossil fuel between 2021 and 2031 9€cents/kWh for CO2-free dispatchable grid power is anticipated to be
competitive in some markets in 2025
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CSP in South Africa?
Favourable factors: – Size and quality of solar resource
– Rapidly increasing indigenous demand
– High level of local supply share of CSP technology (up to 60% by value by 2020)
Issues: – Subsidy schemes and continuity of initiatives
– Financing framework
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Benefits of CSP
• CSP has potential to become a zero-carbon, low-cost dispatchble electricity supplier
• CSP can potentially reduce the amount of (still expensive and inefficient) electric storage systems (pumped hydro, CAES, Power2Gas) needed in the system
• CSP has a high local supply share creating local value and jobs
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Challenges
• parity with fossil fuel energy in the next 10 to 15 years
• grid infrastructure and market mechanisms to integrate large fraction of CSP
• appropriate political and economic boundary conditions in to support long term investments in low-carbon technologies
Recommendations • Develop technical CSP assessment competence in South
Africa – Access to CSP plants of international bidders
– Modeling capabilities
– Test infrastructure
• Decide on the best CSP technology option for South Africa
• Create a sustainable market opportunity for it in South Africa
• Enforce local supply share in future bids
• Support local industry to become part of the local supply chain
• Integrate academic and industrial research in a new programm
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Back-up material
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Cooling tower91.8%
Steam cycle6.1%
Mirror washing2.0%
Potable water0.1%
How does CSP react under desert conditions?
Water consumption
Washing (no recycling yet) 75 l / MWh (low soil.) 30 l /m² year (mirror surface) 0,5 l/m² per wasching cycle Rainfall Cairo = 25 l/m²year
Reflector Soiling • Cleaning of CSP collectors
on a weekly basis,
• PV Systems on a monthly basis in desert environment
• Soiling depends strongly on site (and seasonal) conditions. Variations can be in the order of a factor 2-3
• 5% average soiling leads to revenue losses of 3-6 $/m²year (depending on electricity price)
• Cleaning need 20 – 40 l/m² year
Reflector Degradation?
Glass mirrors have proven high
robustness over >25 years in
operation
Front surface mirrors are more
sensible
DLR has established
accelerated aging methods for
specific reflector types
Dry cooling
Recycling
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Rate of cost reduction depends on learning rate
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
1 10 100 1000Cumulative Capacity (GW)
Re
alti
ve c
ost
re
du
ctio
n
10 % Learning rate
20 % learning rate
