Concentrating Solar Power Technologies Dr. Raed Sherif V.P., International Markets eSolar, Inc.
[email protected] Presented at the iNEMI Alternative Energy Workshop San Jose, California ‐ October 20‐21, 2010
Overview of Solar Technologies Platforms
Solar Technologies
Photovoltaic Silicon Panels
Thin Film Panels
Non‐concentrating 2
Solar Thermal Concentrated PV Panels
Parabolic Trough
Concentrating
Linear Fresnel
Power Tower
Sterling Engine
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, lowest capital 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
Few demonstrations, 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, low potential 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 expensive And it is inefficient (low kWh produced for every kW installed) So you need a lot of semiconductor area
Two solutions were considered ¾ Reduce cost of semiconductor ¾ Use Concentration
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!
6
Meanwhile, PV found a niche application 100
Module Price ($/W) ($2002)
Historical 1980 $21.83/W
Projected 2004! 1985 $11.20/W
10
1990 $6.07/W
1995 $4.90/ W
2000 $3.89/W
2005 $2.70/W
2010 $1.82/W
2013 $1.44/W
1 1
10
100
1000
10000
100000
Cum ulative Production (MW)
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
Picture courtesy of Spectrolab
High‐efficiency solar cells made of III‐V materials used to power spacecrafts
Multijunction PV
Sunlight
TOP CELL
A/R*
MIDDLE CELL 0.6 0.4 BOTTOM CELL 0.2 GaInP2
0 0.25
A/R*
Top Cell: GaInP
0.8 Drawing Not To Scale
INTENSITY (ARB UNITS)
1.0
Contact
0.45
GaInAs 0.65
0.85
Ge 1.05
1.25
1.45
WAVELENGTH (Microns)
Picture courtesy of Spectrolab
1.65
1.85
2
Tunnel Junction Middle Cell: GaInAs Tunnel Junction Bottom Cell: Ge Ge Substrate Contact *A/R: Anti-Reflective Coating
• State of the art is the 3J cell • Typical 3J cell contains 20 layers or more • Divides the solar spectrum (l 8 GWh over a 25 year life more than a thin film panel
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
$30 cents/kWh
$15‐$20 cents/kWh
Under $10 cents/kWh
Research device eff.
40.7%
41.6% (recently 42.3%)
48%
Commercial device 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
Trough Most mature technology (over 500 MW installed) Single axis tracking Synthetic oil Costly heat exchangers Low concentration Medium efficiency (~ 16%)
Linear Fresnel Reflectors Tubes fixed in place Use direct steam Low concentration Low maximum temperature Lowest efficiency (~ 11%) Limited demonstration
Tower Dual axis tracking High concentration High maximum temperature Demonstrated in Solar One, Solar Two, PS‐10, PS‐ 20, Sierra Highest 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
Conventional technology Curved trough mirrors and large heliostats (120 m2) require heavy support structures and expensive manual labor
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
eSolar: Innovative Modular and Scalable CSP Thermal Receiver [direct steam generation]
Receiver Tower South field of tracking mirrors
North field of tracking mirrors
Award‐winning Technology
2010 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 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 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.
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
External boiler designed by Babcock & Wilcox
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
Big savings in Construction Costs! Solar Trough/ Other CSP Towers
eSolar System
Expensive crews, cranes and power tools required, with excavating, welding and fabrication done on‐site
Only hand tools (one ratchet wrench) required to unfold and tighten entire solar field in place with NO ground penetration
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 ensure lower material and labor costs
Mirror field is installed using hand tools with no ground penetration
eSolar’s Core Innovation: Automated Calibration & Tracking System Two‐axis tracking is supported by cameras and proprietary software System of cameras Fully‐automated Heliostat availability > 99.9% Full calibration in
