Concentrated Solar Power (CSP) A World Energy Solution
Transcript of Concentrated Solar Power (CSP) A World Energy Solution
Concentrated Solar Power (CSP)
A World Energy Solution
NATIONAL BOARD
MEMBERS TECHNICAL PROGRAM
October 7, 2009
Steve Torkildson, P.E.Principal Engineer
Concentrated Solar Power (CSP)Clean, sustainable energy
Sierra 5 MweLancaster, CA
PS-10 11MWeSpain
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Concentrated Solar Power (CSP)
• The concept:
– Concentrating solar radiation creates the temperatures needed to drive a thermodynamic cycle
– Concentrating solar energy provides a endlessly renewable, low-cost and non-polluting means of generating electricity for the entire cost and non-polluting means of generating electricity for the entire world.
– Solar electricity production can meet the world’s demand for energy far into the future
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Concentrated Solar Power (CSP)
• The Need:
– Increasing electric power demand
• Worldwide electrical consumption will double by 2040
– Dwindling fossil reserves– Dwindling fossil reserves
– Reduction of carbon emissions
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• The Resource: “Our Sun”
– FACT
• The amount of solar energy striking the earth’s surface in a single hour exceeds the amount of energy consumed worldwide in a calendar year
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• The Resource: “Our Sun”
– FACT
• the amount of solar energy reaching earth yearly
represents ~ 2 times the energy that can, or will be
developed by all of the earth’s non-renewable
resources including coal, oil, gas and uranium
reserves.reserves.
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Total Non-Solar Energy Reserves
Annual Solar Energy
• Solar insolation is the direct measure of solar radiation received on a surface in a defined amount of time
– expressed as average irradiance in W/m2
– often expressed as ‘suns’ with 1 sun = 1,000 W/m2
• The average direct normal solar radiation in the
Solar Insolation
• The average direct normal solar radiation in the earth’s upper atmosphere is ~ 1,366 W/m2 which is attenuated in the atmosphere to ~ 1,000 W/m2
– Factors influencing DNI (Direct Normal Incidence) are:
» solar elevation angle (cosine effect)
» cloud cover
» dust & moisture11
Daily Solar Energy Delivery
8000
10000
12000
delivere
d,
kW
/m2
Winter
Summer
0
2000
4000
6000
6 8 10 12 14 16 18 20
Q-d
elivere
d,
kW
/m
Time of day
Winter
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Thin Film PV/CPVPhotovoltaics
Solar Energy
Direct Conversion - Current Approaches
Solar Energy
30¢ kWh30¢ kWh30¢ kWh30¢ kWh
21¢ kWh
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Note: Cost figures given may not reflect current market. Producers continue to innovate and reduce costs.
Power TowerSolar Thermal Troughs
Solar Energy
Concentration Methods
A variety of approaches demonstrated to date use arrays of hundreds or thousands of heliostats (mirrors) to concentrate the sun’s rays to heat a transfer medium between 500oF and 1,800oF
Power TowerSolar Thermal Troughs
16¢ kWh16¢ kWh 13¢ kWh13¢ kWh16¢ kWh16¢ kWh 13¢ kWh13¢ kWh
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– long runs of parabolic Fresnel* single curvature mirrors
– single axis rotation focus energy on a collector tube
– oil is typical heat transfer medium
– ~ 400oC (750°F) oil produces steam in heat exchanger
– conventional steam turbine
– solar/energy conversion efficiency ~ 15%
CSP Solar Troughs
– solar/energy conversion efficiency ~ 15%
– most notable plants are SEGS installations
» Kramer Junction, CA
» 350 MWe are currently installed.
– The 1st of 9 plants went into operation in 1985
* pronounced: pronounced fre’ nɛl (Wikipedia.org)
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– currently has a 5 MWe plant (Kimberlina) operating in Bakersfield CA
– Linear Fresnel reflectors with linear flat mirrors in lieu of the parabolic mirrors (to reduce cost) and forgoing the Therminol in lieu of directly converting
CSP Solar Troughs
to high temperature steam.
» Direct steam conversion offers a simpler solar integration for existing fossil facilities
– Plans are being formalized to develop & build a 177 MWe plant for PG&E in Carrizo Plains, CA
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� …have been demonstrated successfully at Solar One,
Solar Two, and PS10
� Key development barriers persist…
– Expensive heliostats
– Cost reduction efforts
– Scale-up risk on key components
– Access to transmission / permitting delays
CSP Power Towers ….
– Access to transmission / permitting delays
– Large project cost & risk
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– 11MWe
• saturated steam generator (495oF/580psi)
• 624 mirrors >800,000ft2
• north solar field
ABENGOA Solar PS-10
• north solar field
• tower @ 377 ft
• Receiver eff’y @ 92%
• 30 – minute storage
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• saturated steam generator (495oF/580psi)
• large mirrors (1,291 ft2)
• 1255 mirrors >1,615,000 ft2
• north solar field
• tower @ 525ft
• 235 acres required
ABENGOA Solar PS-20
• 235 acres required
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eSolar Concept
• Small heliostats
• Tracking software creates a virtual parabolic mirror
• Automatic software driven calibration of mirror position
• Maximize factory assembly
• Minimize field assembly
• Utilize existing technologies where feasible
– Conventional steam cycle
– Wind turbine towers
• Rapid deployment
• Goal: solar plant cost = coal plant cost
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The Problem with Solar: Economics
• Conventional Combined Cycle Power plant:
– $1.00 - $1.25/watt installed cap cost + fuel costs + volatility costs + uncertain carbon cost
• Solar Thermal Industry benchmark:
– Solar field ~45% of Total Plant Cost
– Installation/construction ~20% “
eSolar
PS-20
– Installation/construction ~20% “
– Receiver ~10% “
– Power Block ~15% “
• Prevailing Installed Solar Thermal Power Plants:
– $3.5/watt to over $4.00 per watt installed
• eSolar addresses all four major cost components to make solar thermal
power cost competitive
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Why smaller mirrors?
• Lighter
• Less wind load
• No concrete foundation – sits on compacted soil
• Assembly without heavy equipment
• Low cost production due to high volume• Low cost production due to high volume
• Rapid deployment
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Unit
Using computational power to create a system that is:
� Modular
� Pre-fabricated
� Dramatically less expensive
Heliostat
Stick Assembly
Module One tower + receiver
Unit16 ModulesOutput: 46 MW
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• Multiple 46 MW Units can scale easily and quickly
to any generation capacity to meet growing demand
Layout flexible to accommodate land resource availability
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eSolar has addressed traditional CSP challenges by……….
Leveraging pre-fabricated, mass manufactured components
� Assembled in a factory, saving high costs of field construction and civil work
� Flat mirrors are less expensive, faster to manufacture, and easier to deploy
Focus mirrors using software, not concrete and steel
� Breakthrough computer calibration and dual-axis sun-tracking control
Reduce costs through a modular and scalable design
� 46 MW standard units, fast deployment to over 1 GW at a single site
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• Tower height @ 153’
• North & South heliostat fields @6,000 mirrors /field
• eSolar
– 5 MWe demonstration plant @ Lancaster CA
– 1st sun on receiver April 18th 2009
– Key Performance criteria achieved June 20th, 2009
• Heliostat @ 12 ft2
• Total mirror surface @ 144,000 ft2
• Land area @ 10 acres/ module
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eSolar’sSteam Receiver Design Specs
• Natural circulation
• Modular (shippable) configuration (minimum field assembly)
• Weight limitation @ 60 tons
• Tube Materials: Carbon steel & T22
• Peak heat flux @ 130,000 Btu/hr-ft2
• Average flux rates: -• Average flux rates: -
– Evaporator surface @ 45,000 Btu/hr-ft2
– Superheater surface @ 35,000 Btu/hr-ft2
• Extreme Cyclic Duty: -
• Daily start-up and cloud transients
• >20,000 lifetime startup cycles
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Receiver prototype designs
Dual Cavity“External”
Dual Cavity currently operating successfully on Tower 1External receiver commissioning currently underway.
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– Dual Cavity Receiver
• Captures 97% of incident energy
• Superheater surface captures ‘reflected’ radiation
• Lower convection/radiation losses
Prototype designs
•External Receiver
•Surfaces mat -black for max. absorption (94%) of direct
incident radiation
•Higher convection/radiation losses
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Cavity Receiver
– Natural circulation
• 42” steam drum, turbo separators
– Membrane evaporator & pre-heater panels
– ‘tangent-tube’ superheater panels
MCR Steam Conditions:30,000 pph900 psig825oF
Feedwater425oF
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5-MW Sierra Commercial Demonstration
All solar-related components being demonstrated at commercial
plant sizes, mitigating scale-up risk
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Solar Receiver Operational Challenges
• Receiver area inaccessible during operation
– Risk of exposure to solar flux
• Time required for daily inspections
– Lock-out procedure must be followed
– Time to move from tower to tower
– Time to ride service lift to top of tower– Time to ride service lift to top of tower
– Approx. ½ hour per receiver. 16 receiver plant = 8 hours
• Inspection Access
– Improvements needed to provide for inspection, maintenance, repairs.
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