what it takes to harness the sun

WHAT IT TAKES TO HARNESS THE SUNIVANPAH SOLAR TOWER DESIGN

Kristin M. Santamont P.E.Senior Civil Engineer, Bechtel

Corporation© Bechtel 2012 | 1

IVANPAH SOLAR ELECTRIC GENERATING FACILITY

LocationSan Bernardino County, California, USA45 miles South West of Las Vegas

CustomerSolar Partners

Scope of ServiceEngineeringProcurementConstructionStartup

Project Completion2013

Units and Megawatts3 separate power plants totaling 392MW

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“GREEN” POWER GENERATING FACILITY

363,000 tonnes of CO2 emissions avoided each year.

Equivalent to 70,000 cars

140,000 homes powered by the Ivanpah facility

Low impact construction techniques © Bechtel 2012 | 3

TYPICAL UNIT

SRSG

Air Cooled Condenser

Tower Mirror

FieldSteam Turbine Generator

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PROJECT SITE

1

2

3

Project Size 3,600 Acres

Project Capacity Unit 1 = 126 MW

Units 2 & 3 = 133 MW

Solar Field Size Unit 1 = 895 acres

Unit 2 = 1078 acres

Unit 3 = 1209 acres

Number of Heliostats

Total = ~173,500

Unit 1 = 53,500

Units 2 & 3 = 60,000

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173,500 HELIOSTATS

Enough reflective area to cover approximately 600 football fields

Enough mirrors to replace all the windows in the Empire State

Building…54 times

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3,600 ACRE SITE

Manhattan Island

Manhattan Island

1

2

3

~ 6 square miles

Roughly 25% the size of Manhattan

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Solar Tower Structure Design

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SOLAR TOWER STRUCTURE 120’ tall Solar Receiver Steam Generator (SRSG)

54’ x 54’ footprint Each SRSG receives solar flux from mirror field Conventional steel braced frame

339’ tall Tower 70’ x 70’ footprint at base 45’ x 45’ main tower footprint Column splices located for modular erection

Concrete Foundation 120’ x 120’ in plan 9’ thick mat © Bechtel 2012 | 9

SOLAR TOWER 1,800 tons of structural steel

9 Tiers ~40’ tall Lowest 4 Tiers are “stick built” 5 Tiers Ground Assembled as Modules

Columns are 36” f pipe sections API 5L X56 material 1 ½” or 2” wall thickness

2” f A354 Grade BD bolts in splices

HSS16 square vertical braces

Traditional floor framing© Bechtel 2012 | 10

TOWER STEEL ERECTION

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TOWER COLUMN SPLICES

Each column splice utilizes an identical circular pattern of 16 2”f A354 Grade BD bolts

Extra 4 bolts for shear loads at discrete locations only© Bechtel 2012 | 12

SRSG CONFIGURATION

Superheater Panel

Reheater Panel

Steam Generator

Panel

Protection Panel

Protection Panel

3 Stage Steam Generator

700 tons of structural steel for internal framing

Total weight including piping & equipment ~2,000 tons

Traditional framing geometry and member sizes

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SRSG CONFIGURATION

Highly congested volume

External water walls with piping, headers and associated valves

Contains steam drum, silencers, access platforms, etc.

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SOLAR RECOVERY STEAM GENERATOR (SRSG)

“Modularized” in 5 Tiers Ground Assembled and transported

to Tower Lifted in thirds due to weight limits

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STRUCTURAL DESIGN

2007 California Building Code Seismic Design Category C Design Wind Speed 85 mph

Operating wind speed of 30 mph

Flexible Structure Governed by Wind

Flexible Structure Fundamental Period 3.3 seconds

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VORTEX SHEDDING

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WIND TUNNEL TESTING Boundary Layer Wind Tunnel Laboratory at

University of Western Ontario

Performed a Rigid Model Test

The measured cross-wind loads ~3 times calculated along-wind code prescribed load

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TUNED MASS DAMPER Changing foundation and stiffening

structure deemed not practical

Opted for Tuned Mass Damper Solution

Required minimum 5% of critical damping to mitigate cross-wind response to an acceptable level

Other TMD requirements: 30 year design life Operating temperature range 10oF –

150oF

Idealized TMD with Suspended Mass &

Dashpots

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TUNED MASS DAMPER Limited space in SRSG for

addition of TMD. 11’-4” X 11’-4” X 20’-6”

volume

TMD Location between

elevations 435’-5” – 456’-

1”

Volume identified for

TMD

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HELIOSTAT ASSEMBLY AREA

2 Pad Bonding Buildings

Heliostat Storage & Pit Lane

Material Laydown

Assembly Building

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ACKNOWLEDGEMENTS Boundary Layer Wind Tunnel Laboratory

GERB Vibration Control Systems

www.ivanpahsolar.com

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