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 Mwe Lancaster, CA PS-10 11MWe Spain 2
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 world. Solar electricity production can meet the world s demand for energy far into the future 3
Concentrated Solar Power (CSP) The Need: Increasing electric power demand Worldwide electrical consumption will double by 2040 Dwindling fossil reserves Reduction of carbon emissions 4
Current world energy consumption is 15 terawatts 5
By 2050, world energy consumption is estimated to be 50 terawatts 6
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 7
Solar provides more than 1000 times the energy required by current demands 8
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. Total Non-Solar Energy Reserves Annual Solar Energy 9
To generate all of the current US energy demand requires a tract of land 243 miles square 10
Solar Insolation 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/m 2 often expressed as suns with 1 sun = 1,000 W/m 2 The average direct normal solar radiation in the earth s upper atmosphere is ~ 1,366 W/m 2 which is attenuated in the atmosphere to ~ 1,000 W/m 2 Factors influencing DNI (Direct Normal Incidence) are:» solar elevation angle (cosine effect)» cloud cover» dust & moisture 11
Daily Solar Energy Delivery 12000 10000 Summer Q-delivered, kw/m 2 8000 6000 4000 Winter 2000 0 6 8 10 12 14 16 18 20 Time of day 12
Solar Energy Direct Conversion - Current Approaches Photovoltaics Thin Film PV/CPV 30 kwh 21 kwh Note: Cost figures given may not reflect current market. Producers continue to innovate and reduce costs. 13
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 500 o F and 1,800 o F Solar Thermal Troughs Power Tower 16 kwh 13 kwh 14
CSP Solar Troughs long runs of parabolic Fresnel * single curvature mirrors single axis rotation focus energy on a collector tube oil is typical heat transfer medium ~ 400 o C (750 F) oil produces steam in heat exchanger conventional steam turbine solar/energy conversion efficiency ~ 15% most notable plants are SEGS installations» Kramer Junction, CA» 350 MW e are currently installed. The 1 st of 9 plants went into operation in 1985 * pronounced: pronounced fre nɛl (Wikipedia.org) 15
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CSP Solar Troughs 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 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 17
Power Tower Overview 18
CSP Power Towers. 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 Large project cost & risk 19
ABENGOA Solar PS-10 11MW e saturated steam generator (495 o F/580psi) 624 mirrors >800,000ft 2 north solar field tower @ 377 ft Receiver eff y @ 92% 30 minute storage 20
ABENGOA Solar PS-20 saturated steam generator (495 o F/580psi) large mirrors (1,291 ft 2 ) 1255 mirrors >1,615,000 ft 2 north solar field tower @ 525ft 235 acres required 21
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 22
The Problem with Solar: Economics Conventional Combined Cycle Power plant: $1.00 - $1.25/watt installed cap cost PS-20 + fuel costs + volatility costs + uncertain carbon cost esolar Solar Thermal Industry benchmark: Solar field ~45% of Total Plant Cost 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 23
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 Rapid deployment 24
Populating the heliostat field 25
esolar Evolution First production unit running 16 months after test facility demonstration. 26
Starting Small esolar Evolution 1 st steam April 2 nd 2008 Test Facility 27
Using computational power to create a system that is: Modular Pre-fabricated Dramatically less expensive Unit 16 Modules Output: 46 MW Stick Assembly Module One tower + receiver Heliostat 28
Multiple 46 MW Units can scale easily and quickly to any generation capacity to meet growing demand Layout flexible to accommodate land resource availability 29
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 30
esolar 5 MWe demonstration plant @ Lancaster CA 1 st sun on receiver April 18 th 2009 Key Performance criteria achieved June 20 th, 2009 Tower height @ 153 North & South heliostat fields @ 6,000 mirrors /field Heliostat @ 12 ft 2 Total mirror surface @ 144,000 ft 2 Land area @ 10 acres/ module 31
esolar s Steam 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-ft 2 Average flux rates: - Evaporator surface @ 45,000 Btu/hr-ft 2 Superheater surface @ 35,000 Btu/hr-ft 2 Extreme Cyclic Duty: - Daily start-up and cloud transients >20,000 lifetime startup cycles 32
Receiver prototype designs Dual Cavity External Dual Cavity currently operating successfully on Tower 1 External receiver commissioning currently underway. 33
Prototype designs Dual Cavity Receiver Captures 97% of incident energy Superheater surface captures reflected radiation Lower convection/radiation losses External Receiver Surfaces mat -black for max. absorption (94%) of direct incident radiation Higher convection/radiation losses 34
Cavity Receiver Natural circulation 42 steam drum, turbo separators Membrane evaporator & pre-heater panels tangent-tube superheater panels MCR Steam Conditions: 30,000 pph 900 psig 825 o F Feedwater 425 o F 35
5-MW Sierra Commercial Demonstration All solar-related components being demonstrated at commercial plant sizes, mitigating scale-up risk 36
Pointing / Tracking Progress May 7th June 22nd June 22nd
The World s largest digital display? 38
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 Approx. ½ hour per receiver. 16 receiver plant = 8 hours Inspection Access Improvements needed to provide for inspection, maintenance, repairs. 39
Proposals for enhanced inspection capability Generous use of TV cameras to monitor critical areas and instruments Movable access platforms Replace daily start-up inspections with more rigorous weekly inspection 40