1

Solar Pathways to Lower CostSolar Pathways to Lower Cost

June, 2006June, 2006

Herb HaydenHerb HaydenPinnacle West Capital CorporationPinnacle West Capital CorporationParent company to Arizona Public ServiceParent company to Arizona Public Service

2

APS Experience in APS Experience in Solar ApplicationsSolar Applications

ScottsdaleWater Campus

Carol Spring Mountain Telecom

Remote Solar Electric Service Home

Add large and small grid-tied sites

Glendale Airport

OffOff--Grid PVGrid PV--Hybrids (batteryHybrids (battery--generator)generator)

homes and rancheshomes and ranches

some larger systemssome larger systems

GridGrid--tied PV tied PV

PV rooftops, and larger groundPV rooftops, and larger ground--mountedmounted

Sites statewideSites statewide

3

Not shown are APS nonNot shown are APS non--solar projects solar projects ---- Biomass, Biomass, Wind, and Hydrogen Wind, and Hydrogen Fueling StationFueling Station

Arizona

50+ PV Hybrid homes & ranches

4 Large PV Hybrids

Rooftop PV

10+ sites at 100 kW to 5+ MW

APS Solar SitesAPS Solar SitesNATURAL BRIDGES, UTAHNATURAL BRIDGES, UTAH

GRAY WOLF LANDFILLGRAY WOLF LANDFILL

YUMA ARMY PROVING YUMA ARMY PROVING GROUNDSGROUNDS

CAROL SPRING MOUNTAINCAROL SPRING MOUNTAIN

DANGLING ROPEDANGLING ROPE

SAN JUANICO, MEXICO PVSAN JUANICO, MEXICO PV--WINDWIND

FlagstaffFlagstaff

Tempe Tempe STARSTAR

GlendaleGlendale

GilbertGilbert

YumaYuma

EmbryEmbry

ScottsdaleScottsdale

ADEQADEQ

PrescottPrescott

SaguaroSaguaro

More...More...

MARBLE CANYONMARBLE CANYON

LOWELL OBSERVATORYLOWELL OBSERVATORY

ST MICROST MICRO

SAN LUISSAN LUIS

SCOTTSDALE WATER CAMPUSSCOTTSDALE WATER CAMPUS

PRESCOTT AIRPORTPRESCOTT AIRPORT

GILBERT NATURE CENTERGILBERT NATURE CENTER

GLENDALE AIRPORTGLENDALE AIRPORT APS STAR FACILITYAPS STAR FACILITY

YUCCA POWER PLANTYUCCA POWER PLANT

AZ DEPT ENV QUALITYAZ DEPT ENV QUALITY

SAGUARO SOLAR SAGUARO SOLAR TROUGHTROUGH

EMBRY RIDDLE AERO UNIVEMBRY RIDDLE AERO UNIV

FLAGSTAFF SERVICE CENTERFLAGSTAFF SERVICE CENTER

4

Many Solar Many Solar OptionsOptions

Rooftop Tilted PV (APS at Tempe Recycling Center)

Tracking PV and Concentrator PV(APS STAR in Tempe)

Large Solar Thermal Trough Plant (California)

Tracking PV(APS at Embry Riddle University)

5

Need for More SolarNeed for More Solar

Southwestern US goals would require thousands of MW Southwestern US goals would require thousands of MW

Rooftop PV option is currently supported by utility Rooftop PV option is currently supported by utility rebates programs, customer ownedrebates programs, customer owned

Higher output & lower costs are needed for solar to Higher output & lower costs are needed for solar to become a more significant resourcebecome a more significant resource

6

Technology Benefits at Larger ScaleTechnology Benefits at Larger Scale

More solar technology options, efficiencies of More solar technology options, efficiencies of scalescale

Greater energy Greater energy ““yieldyield”” (output kWh per installed (output kWh per installed kW)kW)

ThermalThermal--electric solar options electric solar options ---- energy storage energy storage and gas backupand gas backup

7

APS STAR Site APS STAR Site ---- Solar Test & ResearchSolar Test & Research

8

Location and Tracking Affect ResourceLocation and Tracking Affect Resource

50%

75%

100%

125%

150%

FixedHorizontal

Fixed Latitude TrackingHorizontal

Concentrators TrackingLatitude

Daggett

PrescottPhoenixTucson

Phoenix PVFixed, Tilted used as Baseline

88%

132%

123% 123%

More energy output from More energy output from ““trackingtracking”” the sunthe sun

“PV Tracker” systems --more energy per kW

Fixed, Horizontal

From NREL Redbook data.

PV rated at 1000 W/m2, CPV rated at 850 W/m2 DNI.

9

60%

70%

80%

90%

100%

110%

120%

130%

- 20 40 60 80 100 120 140 160 180 200Cell Rating/Operating Temp F

Concentrating PV

Phoenix in JuneTypical temperature rise of PV cell under full sun is 47 F if back is open to air. If back is foam insulated, temperature rise of 81 F is observed.

Standard PV

Phoenix in June

Phoenix in December

Phoenix in June on Insulated Roof Tiles

Over 1/3 power loss due to heat

Heat and Cold Affect EfficiencyHeat and Cold Affect Efficiency

Phoenix in December

Heat decreases PV output, severely in some casesHeat decreases PV output, severely in some cases

Concentrators are affected less by temperatureConcentrators are affected less by temperature

10

Tracking for Flat Plate and ConcentratorsTracking for Flat Plate and Concentrators

SingleSingle--axis Tracking PV axis Tracking PV systems provide about 20% systems provide about 20% more energy in sunny locationsmore energy in sunny locations

Solar trough systems also use Solar trough systems also use singlesingle--axis tracking to enable axis tracking to enable sunlight concentrationsunlight concentration

High concentration systems High concentration systems such as CPV require 2such as CPV require 2-- axis axis trackingtracking

11

APS Prescott Airport Solar SiteAPS Prescott Airport Solar Site

3,400 kW currently, of over 6 MW planned3,400 kW currently, of over 6 MW planned

Large tracking PV arrays, and new CPV systemsLarge tracking PV arrays, and new CPV systems

12

APS Single Axis Tracker APS Single Axis Tracker –– MultiMulti--megawatt Fieldmegawatt Field

13

Summer PV Output ComparisonSummer PV Output ComparisonJuly 21, 2004

16%

32%

11%

27%

41%

67%

49%55%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

3:00 AM 6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM 9:00 PM

5 PM

6 PM

Fixed Horizontal

Fixed Tilted

Tracking PV

CPV

Highest Summer Load Hours

Tracking PV provides higher capacity late in the dayTracking PV provides higher capacity late in the day

Systems shown are in Phoenix area, using DC PV ratingsSystems shown are in Phoenix area, using DC PV ratings

14

Winter PV Output ComparisonWinter PV Output ComparisonJanuary 8, 2004

36%

59%

56%

66%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

6:00 AM 9:00 AM 12:00 PM 3:00 PM 6:00 PM

Fixed Horizontal

Fixed Tilted

Tracking PV

CPV

CPV and Tilted installations have highest winter peaksCPV and Tilted installations have highest winter peaks

Output from Horizontal PV systems is much reducedOutput from Horizontal PV systems is much reduced

15

2003 Solar Results 2003 Solar Results ---- Energy per kW RatingEnergy per kW Rating

60%

80%

100%

120%

140%

Desert

Challenger

GilbertNAU

Tempe R

ecycle

Scotts

dale Park

ing

ST Micr

o Roofto

p

STAR Park

ingMTA2MTA3YumaGilb

ertGlen

daleOPV1

Scotts

dale Eas

t

Scotsd

ale West

ERAUW1 W3 E1 E2 E3 E4 E5 G2 G3

Fixed Latitude PV --used as 100% reference

Horizontal resource --88%

Tracking resource --123% Tracking PV

Fixed Horizontal PV

CPV

16

$8,300

7500

$5,500

9500

$/KWdc 5yr kWh

Retail Fixed PV

Large PV Tracker

Net Cost Result5-yr. kWh per $

0.9

1.7

RetailFixed PV

Large PVTracker

PV Energy Cost ComparisonsPV Energy Cost Comparisons

Nearly twice the energy Nearly twice the energy per dollar from solar at per dollar from solar at larger scalelarger scale

17

Concentrators Concentrators –– Where They FitWhere They FitM

atur

e C

ost P

oten

tial

Minimum Installation Size

CPVDish

Solar Trough (CSP)

PVNow over 1000 MW/yr.

New Solar Concentrators

LowLow--cost potential, at moderate volumecost potential, at moderate volume

Require sunny climates, MW scaleRequire sunny climates, MW scale

18

APS 1 MW Solar Electric TroughAPS 1 MW Solar Electric Trough

First First solar trough since 1992solar trough since 1992

First ever at 1 MW size First ever at 1 MW size ----helpful for markethelpful for market--entry and entry and remote useremote use

Water cooling usedWater cooling used

Thermal storage & fuel Thermal storage & fuel backup can be addedbackup can be added

19

APS Saguaro Solar Trough Field (1 MW ORC)APS Saguaro Solar Trough Field (1 MW ORC)

20

1 MW Organic 1 MW Organic RankineRankine Cycle TurbineCycle TurbinePentane working fluid, water cooledPentane working fluid, water cooled

Not as efficient as larger steam systems, but proven with Not as efficient as larger steam systems, but proven with geothermal plantsgeothermal plants

21

Solar Trough ORC SchematicSolar Trough ORC Schematic

22

23

ORC Control Monitor DisplayORC Control Monitor Display

24

Dish Stirling Dish Stirling –– SAIC with STM at APSSAIC with STM at APS

25

SES at Sandia LabsSES at Sandia Labs

26

Concentrating PV TechnologyConcentrating PV Technology140 kW Amonix Field

(APS STAR in Tempe)

Good for sunny regions, like US southwest

High efficiency PV cells -- 26% with silicon

500 kW installed by APS

27

Concentrating Sunlight Concentrating Sunlight Dramatically Reduces Cell SizeDramatically Reduces Cell Size

-50

0

50

100

150

200

250

Wat

ts A

C pe

r 6" w

afer

Conventional PV WafersAmonix PV Wafers

Size indicatesthe PV cell size for same power

(this is Amonix)

(this is Regular PV)

300 times more energy per cell area than regular PV300 times more energy per cell area than regular PV

Higher concentration and higher efficiency will lower costsHigher concentration and higher efficiency will lower costs

28

CPV ManufacturingCPV Manufacturing

USUS--made PV Cells, lenses, tracker made PV Cells, lenses, tracker structure, controlsstructure, controls

$4/W possible at 10 MW per year $4/W possible at 10 MW per year

Under $3/W is possible with future Under $3/W is possible with future efficiency gainsefficiency gains

29

CT/Spectrolabs Microdish(APS STAR in Tempe)

New New MultiMulti--Junction CPVJunction CPV

World’s First Grid-Tied High Concentration Multi-junction PV

Advanced “space” cells -- same as used on Mars Rovers

Can reach 33% efficiency or more

Development with Spectrolabs, Concentrating Technologies and National Renewable Energy Lab

30

Need for Larger Scale SolarNeed for Larger Scale Solar

Solar appears to be the only option to meet large scale Solar appears to be the only option to meet large scale renewables goals renewables goals

US incentives today are primarily US incentives today are primarily ““customercustomer--onlyonly”” –– a major a major barrier to substantial solarbarrier to substantial solar

In Europe, 50c/kwh premium for solar energy is profitable and In Europe, 50c/kwh premium for solar energy is profitable and driving large scale solar investmentdriving large scale solar investment

Concentrating resource in US southwest is excellent Concentrating resource in US southwest is excellent ––immediate cost potential of under 20c/kWh, possibly 10c/kWh immediate cost potential of under 20c/kWh, possibly 10c/kWh with time and investmentwith time and investment

Arizona State University 30kW PV System on Parking Structure -- Provides Power to Supplement Daytime Lighting of Parking Structure

Yavapai-Apache Nation30kW PV System on Parking Structure

City of Rohnert Park, CA30kW PV System on Roof of Sports Center Complex

32

PV Projects in ProgressPV Projects in Progress

•• Northern Nevada Correctional Center: 30kW Mounted on Roof of NewNorthern Nevada Correctional Center: 30kW Mounted on Roof of NewBiomass Facility (also in progress)Biomass Facility (also in progress)

•• City of Flagstaff, AZ: 15kW Mounted on Covered Entryway and WallCity of Flagstaff, AZ: 15kW Mounted on Covered Entryway and Walls s

•• Design and Construct Solar Hybrid Project (100 kW) to Provide PoDesign and Construct Solar Hybrid Project (100 kW) to Provide Power wer to a Remote Region at the Western Edge of the Grand Canyon for tto a Remote Region at the Western Edge of the Grand Canyon for the he HualapaiHualapai Tribe Tribe