Post on 12-Sep-2021
Concentrating Solar Power Technologies
Dr. Raed SherifV.P., International Markets
eSolar, Inc.raed.sherif@esolar.com
Presented at the iNEMI Alternative Energy WorkshopSan Jose, California ‐ October 20‐21, 2010
Overview of Solar Technologies Platforms
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Photovoltaic Solar Thermal
Silicon Panels
Thin Film Panels
Concentrated PV Panels
Solar Technologies
Power Tower
Parabolic Trough
Linear Fresnel
Sterling Engine
Non‐concentrating Concentrating
Technology Efficiency Status Markets Pros Cons
Si panels 14% - 22% DC Standard, mature (GW deployment), 75% market share
Primarily rooftops and commercial ,and lately utility
Diffuse sun, established, proven cost reduction path
Intermittent, no clear path for higher efficiency , higher investment to set up manufacturing
Thin films ~ 11% DC CdTe of FS 25% market share, other thin film about ready to enter the market
Utilities Diffuse sun, lowestcapital cost
Material set, low efficiency, high BOS costs
CPV 25% - 32% DC Fragmented, emerging, many technologies, less than 20 MW installed
Commercial, utilities
Very high efficiency potential, low use of semiconductor, lower manufacturing set up costs
Fewdemonstrations, use of DNI only
CSP-Trough 14-15% AC Mature, standard, over 650 MW installed and many PPA’s including storage
Utility power generation
Established, over 20 + years, can be hybridized, storage capability
Water use, use of DNI only, lowpotential for cost reduction
CSP- CLFR 11% AC Under 10 MW installed,but finalist in the Solar Flagship of Australia
Industrial steam, utility power generation
Low capital cost,steam suitable for industrial process heat
Water use, use of DNI only, low efficiency, low steam temperature
CSP- Tower 18% - 22% AC Different solar fields,under 40 MW installed, PPA’s signed for hundreds of MW
Utility power generation
High efficiency, path for low LCOE, storage, hybrid
Water use, use of DNI only
Concentrating Photovoltaic
History
CPV Module Components
The Promise of CPV
Status of the Technology
Opportunities & Challenges
History
Go back to 1980 and ask: why is solar expensive?
To a first degree, the semiconductor is expensiveAnd it is inefficient (low kWh produced for every kW installed)
So you need a lot of semiconductor area
Two solutions were considered
Reduce cost of semiconductor
Use Concentration
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Some Historical CPV Systems
Interest in CPV evident in the 1970’s and 1980’s systems
But back then, CPV was too expensive – the technology was not ready!
Meanwhile, PV found a niche application
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1 10 100 1000 10000 100000
Cumulative Production (MW)
Mod
ule
Pric
e ($
/W) (
$200
2)
Historical
Projected 2004!1980
$21.83/W1985
$11.20/W 1990$6.07/W 1995
$4.90/ W 2000$3.89/W 2005
$2.70/W2010
$1.82/W2013
$1.44/W
PV was cost efficient in remote applications, then through FIT and incentive programs, gained market in grid‐connected
Projections of lower module cost with higher volumes, increased efficiency, and automation have come true – except the time of silicon shortage
A New, Disruptive Technology
High efficiency, super expensive “multi‐junction” solar cells made their way into the domain of solar energy because of space application, building on the “dual‐junction” technology that was developed by the DOE
High‐efficiency solar cells made of III‐V materials used to power spacecrafts
Picture courtesy of Spectrolab
1.0
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00.25 0.45 0.65 0.85 1.05 1.25 1.45 1.65 1.85
INTE
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(AR
B U
NIT
S)
WAVELENGTH (Microns)
TOP CELL
MIDDLE CELL
BOTTOM CELL
GaInP2 GaInAs Ge
Multijunction PVSunlight
• State of the art is the 3J cell• Typical 3J cell contains 20 layers or more• Divides the solar spectrum (l < 1.750 mm) to maximize efficiency
Picture courtesy of Spectrolab
Draw
ing N
ot To
Sca
le
ContactA/R*
Top Cell: GaInP 2
Tunnel Junction
Bottom Cell: Ge
Ge Substrate
Contact
A/R*
Tunnel Junction
Middle Cell: GaInAs
*A/R: Anti-Reflective Coating
CPV Module Components
• Primary optics collect the DNI light
• Secondary optics homogenize the light and focus more on the PV cell
• High efficiency cell packageto receive concentrated light
• A system of heat removal and electric connections
• Dual‐axis tracking
Example of a CPV module‐ picture courtesy of Amonix
SolarCell
Receiver
Sub-Module Module (total of 50 modules mountedon a dual-axis tracker)
Concentrating Photovoltaic Receivers/Cell Assemblies
CPV Receiver/Cell Assembly‐ Electric connection‐ Heat dissipation‐ Reliability‐ Cost
Example of a CPV module‐ picture courtesy of Sol3G
The promise of CPV‐ Path to Lowest LCOE
• Efficiency is leveraging in reducing LCOE
• Cell utilization is very small (1/1000 of the silicon cells)
• Cells replaced with conventional materials (steel, aluminum, glass)
• Promises of higher efficiency and lower cell costs have been coming true
• Field demonstrations and IEC qualification testing show technology to be robust
• Industry is nowhere near taking advantage of economies of scale yet
CPV Advantage in Performance• Dual‐axis tracking provides higher kWh/kWp, and higher capacity
factor‐ almost 60% higher than stationary flat plate Si module
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6 8 10 12 14 16 18Local time (h)
1 Amonix = 8.8 kWh/kW
J Single axis = 7.2 kWh/kW
H Fixed Flat Plate = 5.0 kWh/kW
• For a 1 MW plant, CPV system would produce >8 GWh over a 25 year life more than a thin film panel
Picture courtesy of Amonix
CPV Chip Efficiency vs. Other Technologies• CPV chips efficiency increase about 1% per year: 40% commercial by end of
2010 , 42‐43% by 2012 and path for > 45%, while prices going down due to economies of scale, automation, and learning
Picture courtesy of NREL
Where the CPV Industry is now, and where it is heading
Parameter Status in 2007 Status in 2010 Projected by 2015
$/W installed $7‐$10/W $4‐$6/W <$3/W
Cents/kWh >$30 cents/kWh $15‐$20 cents/kWh Under $10 cents/kWh
Research device eff.
40.7% 41.6% (recently 42.3%) 48%
Commercialdevice eff.
35‐37% 39‐40% 42‐43%
Commercial cell cost
$10‐$15/sq. cm $6‐$8/sq. c m $3‐$5/sq. cm
Demonstrations Under 1 MW 4‐6 MW with PPA’s signed for 30+ MW
Hundreds of MW
Source: Dr. Sarah Kurtz of NREL Report on CPV
Opportunities & Challenges
• Technology has the potential to reach low LCOE
• Promises of commercial chip efficiencies of 40% and above are happening‐ chip efficiencies of 50% and above are doable!
• Many new chip suppliers, ensuring continuous drive to increase efficiency, reduce cost, and meet volume demands
• IEC qualification standards established, and CPV modules are meeting the standards
• Field demonstrations are proving viability of the technology
• PPA’s are being signed
• No economies of scale achieved yet
• Bankability issues
• Fragmented technology, no standardization
Concentrating Solar Power Tower
Why Tower?
Traditional Obstacles to CSP
Innovations in CSP Tower
Opportunities & Challenges
Among CSP technologies, the CSP Tower offers the best opportunities for scalable solar power at the lowest cost
Linear Fresnel Reflectors
Tubes fixed in placeUse direct steamLow concentrationLow maximum
temperatureLowest efficiency (~ 11%)Limited demonstration
Trough
Most mature technology (over 500 MW installed)Single axis trackingSynthetic oilCostly heat
exchangersLow concentrationMedium efficiency (~
16%)
Tower
Dual axis trackingHigh concentrationHigh maximum
temperatureDemonstrated in Solar
One, Solar Two, PS‐10, PS‐20, SierraHighest efficiency (18‐
22%)
Question:
Why is CSP expensive?
Materials, construction and installation have been costly for CSP
Traditional CSP requires intensive field construction – cranes, power tools, and heavy civil work with expensive foundations
Mirrors use up large amounts of steel and concrete to resist wind loads
Precision installation, calibration, and alignment are time consuming
Source: Abengoa PS‐10 project Lifting of a trough during construction
Trough mirror assembly on site with large steel support structures
Other power tower heliostats require 3’ diameter steel posts set 20’ into the ground
The actuator is large and heavily engineered
Conventional technology
Curved trough mirrors and large heliostats (120 m2) require heavy support structures and expensive manual labor
eSolar: Innovative Modular and Scalable CSP
South field of tracking mirrors
North field of tracking mirrors
Receiver Tower
Thermal Receiver [direct steam generation]
Award‐winning Technology2010 World Economic Forum Technology Pioneer Award
2010 Renewable Energy World’s “Renewable Project of the Year”
2009 Power Engineering “Best Renewable Project of the Year”
Commercial Demonstration: Sierra SunTower Project
The Sierra SunTower produces 5 MW and consists of 2 modules side‐by‐side in Lancaster, California. Each module has 12,000 tracking mirrors focusing light on a receiver atop a 60 meter tower.
Concept of a power plant using 12 modules
side‐by‐side feeding one steam turbine to
form a 46 MW power plant.
Each module produces 2.5‐2.8 MW
All solar field components have been demonstrated at commercial scale
46 MW units fit on a 250 acre land (~ 1 square km)
Can be deployed in 18‐22 months
Close‐up view of the mirror field. Notice the fact that there is no ground penetration. Frames come pre‐wired from the factory.
Pre‐Fabricated Components for Easy & Rapid Construction
Pre‐fabricated mirrors and frames arrive in standard shipping containers on site
Simple, linear design and field layout reduce high ground preparation costs
Standard 210’ (65 m) wind towers are repurposed to host receivers, expediting the permitting process
External boiler designed by Babcock & Wilcox
Big savings in Construction Costs!
Expensive crews, cranes and power tools required, with excavating, welding and fabrication done on‐site
Solar Trough/Other CSP Towers
Only hand tools (one ratchet wrench) required to unfold and tighten entire solar field in place with NO ground penetration
eSolar System
Cost Reduction and Local Manufacturing Opportunities
Small, flat mirrors require less steel, and can be manufactured locally
Low profile installation reduces construction equipment and labor cost
Pre‐fabricated components requiring less skilled labor for assembly on site
Small, flat mirrors ~ 1 sq. meters ensurelower material and labor costs
Mirror field is installed using hand tools with no ground penetration
Automated solar field calibration
System of cameras
Fully‐automated
Heliostat availability > 99.9%
Full calibration in < 20 days
eSolar’s Core Innovation: Automated Calibration & Tracking SystemTwo‐axis tracking is supported by cameras and proprietary software
Before calibration After calibration
Individually Controlled Mirror Field
eSolar Automatic Heliostat Cleaning Robot
Cleaning position where the rows of mirrors face each other and an eSolar proprietary cleaning robot move between rows
Sierra SunTower
All information contained in this presentation is confidential.No reproduction or distribution of this material is permitted without prior authorization from eSolar.
First Commercial Demonstration
Over 24,000 mirrors, 2 towers, one power block
Break ground July 2008, supply electricity to grid August 2009
Sierra SunTower – Time Line
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Only operating solar tower power plant in the U.S. and one of only three in the world
All information contained in this presentation is confidential.No reproduction or distribution of this material is permitted without prior authorization from eSolar.
Sierra SunTower
Validates eSolar’s technology; 3rd party engineer’s studies complete
Operational history matched or exceeded company forecasts
Small form factor enabled siting of power plant close to load
12‐month construction period
Continues to provide invaluable data to further improve future power plants
2008 2009
June Construction begins
December Heliostats installed
April First Sun
July First Sync
August Unveiling
2010
Official Opening August 5, 2009
Sierra SunTower: Summary of Daily Performance
3All information contained in this presentation is confidential.No reproduction or distribution of this material is permitted without prior authorization from eSolar.
eSolar’s calibration system has allowed it to precisely predict receiver thermal energy absorption
Predictive ability has consistently improved throughout Sierra SunTower’s operational life
Energy absorption model is transferable globally to large scale power plants
“If you want to find a new idea, read an old book!”Bobby Fischer
Thought