02 Renewable Energy Overview

Sept. 20, 2006 ERCOT Update

ERCOT connections to other grids are limited to direct current (DC) ties, which allow control over flow of electricity

North American Interconnected Grids

The ERCOT grid: One of 9 ISOs in North

America Covers 75% of Texas

land Serves 85% of Texas

load 38,000 miles of

transmission lines >550 generation units 62,429 Megawatts peak

demand (set 8/17/06) Single point of control

Interconnection

Sept. 20, 2006 ERCOT Update

ERCOT - Transmission Additions and Upgrades

38,000 miles of transmission lines

8,000 miles of 345kV lines

16,000 miles of 138 kV lines

1,000 Miles of new transmission since 1999 including 700 miles of new 345 kV lines

1,500 miles of transmission lines upgraded since 1999

Numerous substation additions and upgrades

Significant additional projects underway

1940 1950 1960 1970 1980 1990 2000 2010 20200

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Chart derived from DOE Annual Energy Review 2003 data. Courtesy Dr. Santoso.

The Fraction of Primary Energy Used for Electric Generation Continues to Grow

How Electric Consumption Impacts How Electric Consumption Impacts Emissions (3Emissions (3--1 Rule)1 Rule)

5Typical Electric System

We Love to Use Electricity

Big plug, little outlet!

The 3 to 1 rule to produce 1 kWh of electricity, it takes 3 kWHof fuel

If you work hard at manual labor all day, you will produce about 1 kWh of energy

1 kWh of electrical energy cost about 12 - 14 cents

Some facts:

Conservation is an Important Part of the Energy Solution

Used to generate light

But it actually creates more heat than light, and your air conditioner has to remove the heat!

60W, 8760 Hours $74

For same light level, 14W

14W, 8760 Hours $17

Compare Incandescent and Compact Fluorescent Lights

Improving Building Efficiency is a Big Part of the Energy Solution

Proper orientation and design of structure

Proper design and installation of HVAC

Proper installation of insulation

Reduced air leakage

Water conservation

Efficient windows

Efficient lighting

Efficient appliances,

equipment

9October, 2007

The Big Picture

Section 1 A Global Perspective

Population expected to reach 8 billion persons by 2030

95% of population growth expected to occur in non-OECD

U.S. Dependence on Foreign Oil

Saudi Arabia 26%Iraq 11%Kuwait 10%Iran 9%UAE 8%Venezuela 6%Russia 5%Libya 3%Mexico 3%China 3%Nigeria 2%U.S. 2%

U.S. 26%Japan 7%China 6%Germany 4%Canada 4%Russia 3%Brazil 3%S. Korea 3%France 3%India 3%Mexico 3%Italy 2%

Have OilHave Oil Use OilUse Oil

The U.S. uses more than the next 5 highestconsuming nations combined.

The U.S. uses more than the next 5 highestconsuming nations combined.

Updated March 2003. Source: International Energy Annual 2001 (EIA), Tables 11.4 and 11.10.

11October, 2007

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GDP per capita (PPP, $1995)

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Source: UN and DOE EIA

Energy Use Grows With Economic Development

US

Australia

BrazilChina

India

S. Korea

Mexico

Ireland

Greece

FranceUK Japan

Malaysia

Energy demand and GDP per capita (1980-2002)

Chinese population 1.3 billion today

40% of worlds coal last year

Use grew 13% last year alone

2006 brought on 50 gw of new coal construction

12October, 2007

Global CO2 Emissions

Source: ExxonMobil Outlook for Energy A View to 2030

Source: Wood McKenzie

49% Imported!

OIL- U.S. Consumption

67% imp

orted!

The worlds existing 435 nuclear reactors currently need 180 million pounds of uranium each year.

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Million Pounds

Needed Produced

80 million pound gap

Power Generation

Usually based upon the rotation of a dynamo

But what causes the rotation?

Conventional Gas-Fired Steam Power Plant

Natural Gas, Coal, Nuclear

Large Generators

500 MW

750 MW

1000 MW

19October, 2007

A Time of Increasing Power Plant Construction Costs Compounds the Difficulty

11951337

629 704

423 458

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Pulverized Coal High-efficiency gas (CCGT) Low-efficiency gas (GT)

Source: Morgan Stanley, Electric Utility View, July 31, 2007

The Texas Energy PictureThe Texas Energy PictureOil production peaked in 1972Texas became a net energy importer in

1993

5th largest energy user in the worldTexas accounts for 12% of U.S. energy

consumption, why?60% of US petrochemical production25% of US refining capacity19 million automobiles22 million population

The Texas Energy PictureThe Texas Energy Picture

Annual growth in electrical use averaged +3.5% over last 10 years

437 electric generating plantsElectric generating capacityNatural gas 49%Coal 39%Nuclear 10%Renewable* 2%

*Leads US in renewable energy potential

22October, 2007

ERCOT Load

62,339 MW summer peak

demand Majority of load is

concentrated in eastern half of

state

23October, 2007

Winter, Spring, and Summer Day Load Shapes with Fuel Mix

MW

MidnightNoon

MW

Noon Midnight

MW

Noon Midnight

Sept. 20, 2006 ERCOT Update

Other Long-Term Reliability Factors

Region also needs additional fuel diversity

Reduces vulnerability to supply disruption and volatile pricing

Natural gas produces over 40% of the electric energy utilized on the ERCOT grid and always sets the marginal price

Sept. 20, 2006 ERCOT Update

20-Year Load & Generation Maturity Scenarios

This gap must be filled with new generation to maintain reliability

Generation units are typically retired after 30-50 years of service

Predicted Texas Electric Energy Usage

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600,000

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

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UP, UP, UP

High upfront cost, not responsive

No emissions, no fuel cost, offsets summer peak load

Intermittent$314Solar PV

Not dispatchable, not responsive, transmission needs, low value on-peak

No emissions, no fuel cost, low operating cost

Intermittent$39-53Wind

Lead time, security, spent fuel

Stable cost, no emissions, slow responsive

Base load$36-42Nuclear

Volatile fuel costShort lead time, quick start, very responsive

Peak load$74-115Nat. Gas Combustion Turbine

Volatile fuel costShort lead time, responsive

Base load$52-69Nat. Gas Combined Cycle.

Emissions, long lead time, high up-front costs

Stable cost, slow responsive

Base load$36-40Coal

DrawbacksBenefitsCharacteristicCost / MWh

Resource

Characteristics of Generation Options

Other Ways to Rotate a Generator

29

Why Renewables?

Global climate change

Carbon emissions limits and/or taxes

Green power marketing programs

Declining costs

Public support

30

Renewable Technologies

Wind

Solar Geothermal Hydro

TidalWave

Biomass

Renewable Energy Costs Have Decreased Historical and Projected

Costs as percentage of 1980 levels

Source: NREL 2005, 2002

2006

32October, 2007

Renewable technologies at various stages of development and deployment

Renewable Technologies in Texas

As of July 31, 2007

Other2%

Hydro5%

Wind93%

Technology Existing New TotalBiomass - 12.2 12.2 Hydro 197.0 10.3 207.3 Landfill Gas 6.3 54.3 60.6 Solar - 1.2 1.2 Wind 115.8 3,823.3 3,939.1

Total 319.1 3,901.3 4,220.4

Renewable Generating CapacityInstalled in Texas

(MW)

34

Why Wind?

Availability

Cost

Short Construction Lead-Time

Ease of Interconnection

Public Acceptance

Wind Power Has Been Used for a Long Time

US Wind Energy Outlook

Total U.S electricity generation in 2002: 3,800 billion kWh Total electricity potentially generated by wind: 11,000 billion kWh

annually, three times the electricity generated in the U.S today.

USWindEnergyResources

WindEnergyProjectsintheU.S(6/30/2007)

25 States (+D.C.) with an RPS

1.5 Megawatts

400 Watts(on display in the lobby)

Wind Turbines Can Be Large or Small

Skystream Residential Installation

A Modern Wind Turbine

May 2003May 2003

Wind PowerWind Powers Places Place Important part of mix Free fuel No emissions management

Maturing technology Cost competitive Predictable at proven sites Low risk at proven sites

Fastest growing source Future looks bright

desertskywind.com

Texas: #1 in Wind Power

Consider Our State. We Lead the US in Wind Power Production

Texas has more renewable energy (wind + solar) potential than any other state.

but it is still only about 3% of the annual electricity used.

Realistic targets are for the wind percentage to rise to 10% of electricity consumed.

26

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520

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60 MW1318

Silver Star

175 MW

Gulf Wind I-III400 MW each

1617, 21, 32

19, 22, 23 and 24

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Off-Shore Wind150 MW

Orion Energy

Wild Horse60 MW

Snyder63 MW

Roscoe209 MW

Ocotillo59 MW

7

Texas Wind Farms

Map as of 9-30-2007

12

2528

31 33

Goat Wind150 MW

Whirlwind60 MW

Stanton101 MW

Barton Chapel120 MW

CapacityNo. Name (MW)1 Kunitz 45 2 Big Spring Wind Farm 34 3 Southwest Mesa 75 4 Delaware Mountain Wind Farm 30 5 West Texas Project 7 6 Hueco Mountain Wind Ranch 1 7 Indian Mesa 83 8 Woodward Mountain Ranch 160 9 Trent Mesa 150

10 Desert Sky 161 11 King Mountain Wind Ranch 277 12 Llano Estacado Wind Ranch 80 13 Sweetwater Wind Power 38 14 Green Mtn. Energy Wind Farm at Brazos 160 15 Aeolius Wind 3 16 Callahan Divide Wind Farm 114 17 Sweetwater Wind Power II 98 18 Buffalo Gap Wind Farm 120 19 Horse Hollow Wind Farm 221 20 John Deere (3 Community-Owned Projects) 30 21 Sweetwater Wind Power III 129 22 Horse Hollow Wind Farm II 186 23 Horse Hollow Wind Farm III 224 24 Horse Hollow Wind Farm IV 115 25 Red Canyon 1 84 26 Forest Creek Wind Farm 124 27 Wolfe Flats Wind Farm 10 28 Camp Springs 134 29 Mesquite Wind Farm 200 30 Sand Bluff Wind Farm 90 31 Buffalo Gap II Wind Farm 233 32 Sweetwater Wind Power IV 400 33 Post Oak Wind 200 34 Capricorn Ridge Wind Farm 1 200 35 Capricorn Ridge Wind Farm 2 150

Total 4,366

29

3034 and 35

47October, 2007

Draft CREZ PUCT Designations

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5,2159,10

2,8905, 6

3,7204

4,5601, 2

Planned New Wind Capacity

(MW)

Wind Zone

5, 6

1, 2

9, 10

4

19

48October, 2007

Potential Wind Resource

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Nearly 100,000 MW above 35% capacity factor (CF)

Concentrated in western half of state

Existing system from west Texas fully subscribed

Significant distances and costs associated with adding bulk transmission

Currently approximate west to east transfer capacity 3,200MW

200 miles

150 miles

215 ft

115 ft

330 ft

A Typical Modern Wind Turbine is About 1.5 MW

About 100 wind turbines in a wind farm

Operate at 10 20 RPM,

with wind speed range 8 56 MPH

My daughter Claire enjoying her family vacation to the Desert Sky Wind Farm in West Texas

Eastern New Mexico Wind Farm

52

Forest Creek Wind Farm Near Big SpringSiemens 2.3 MW Wind Turbines

55

Texas Offshore Wind Project

Galveston Off-Shore Wind Announced in October, 2005 Located off-shore (Galveston

Island) Located on leased state-owned

land (managed by the Texas General Land Office)

150 MW capacity 3 MW turbines (50) 260 Hub Height (80 meters) 250 Rotor Diameter

Commercial Operation Date: TBD

56

Location

GalvestonIsland

10.36 milesBoundary of Texas lands

Site

57

Texas Second Offshore Wind Project

Corpus Christi Project Announced in May, 2006 Located about 10 miles off-

shore (near Baffin Bay, south of Corpus Christi)

Located on leased state-owned land 39,900 acres (managed by the Texas General Land Office)

500 MW capacity Cost: $1 Billion to $2 Billion Commercial Operation Date:

TBD (at least 4 years after construction begins)

Wind Turbine Technology Today

Several well-established global manufacturers

Mitsubishi (Japan)

Suzlon (India)

GE (US)

Siemens (Germany)

Vestas (Denmark)

Gamesa (Spain)

Typical wind turbine specifications Capacity: 2 to 3 MW (net)

Hub Height: 80 to 90 meters

Rotor Diameter: 90 to 100 meters

Typical costs: $1,500/kW to $2,000/kW

59

Wind Turbine Nomenclature

Typical Parameters: Hub Height = 80 meters Rotor Diameter = 88 meters Swept Area = 6,082 sq. meters Cut-in Windspeed = 4 m/s Rated Windspeed = 14 m/s Cut-out Windspeed = 25 m/s

60

Inside Nacelle

Source: GE Wind

May 2003May 2003

GE Wind 1.5 OperationGE Wind 1.5 Operation

Operates in 8-56 MPH wind Electronically controlled, Remotely monitored Each turbine self-contained independent power plant Onboard weather station, Yaw control facing wind Variable speed via blade pitch Operates at 10-20 RPM Rotor/blade assembly, Generator speeds 850 to 1440 RPM

desertskywind.com

62

Comparative Heights of the Wind Turbines

Feet

Suzlon S88(2.1 MW)

Total Height: 133 meters (433 feet)Rotor Diameter: 88 meters (289 feet)Hub Height: 80 meters (263 ft)

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Statueof

Liberty

Total Height : 89 meters (290 feet)Rotor Diameter: 47 meters (154 feet)Hub Height: 65 meters (213 ft)

Vestas V47(660 kW)

Carter 300(300 kW)

Total Height: 200 feetRotor Diameter: 79 feetHub Height: 160 ft

GE Wind TurbinesGE Wind TurbinesMain Data:

- Generator capacity: 3600 kW

- Control: Pitch

- Rotor speed: 8.5 15.5 Rpm

- Swept area: 7854 m2

- Rotor diameter: 104 m (341 ft)

- Tower options: 100 - 140m(328 to 459 ft)

GE W I N D - 3.6 Offshore

Boeing 747-200

65

Issues Facing Wind Generation

Timing of Production

Impact on Grid Operations

Transmission Congestion

Environmental and Social Impacts

Impact on Grid Operations

Voltage support Reactive compensation Responsive Reserves Grid Stability

EECP CommunicationsJune 9, 2006 67

Wind Data

Sample Generator Output Series (Site in McCamey Area)

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Timing of Production

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TXU Load Wind Project Output

Summer Peak Month Coincidence

Average Hourly Profiles - August 2000

20,993 MW

CapacityValue

at Peak= 10.9%

3.7 MW

May 2003

O&M O&M -- Planned MaintenancePlanned MaintenanceSemi-annual routine planned maintenance Lubrication, yaw and pitch system, generator,

gearbox filter inspections Drive train alignment Blade zero adjustments Wind vane/anemometer checks Converter cleaning and testing Cleaning and inspection of nacelle and tower

equipment

Note: Each turbine requires about 20 hours of planned maintenance per year, generally split between low wind periods in spring & fall.

May 2003

O&M O&M -- RoutineRoutineCorrective MaintenanceCorrective Maintenance

About 6 O&M Technicians are fully engaged in correcting daily turbine issues (about 75% of time spent troubleshooting and 25% repairing)

Most common turbine technical problems are associated with pitch system and converter (instrumentation and electronics).

Note: The most difficult issue currently facing wind power system owners is probably the shortage of qualified technicians. Given that many technical tasks occur in the nacelle, the work is physically demanding as it requires climbing. Although pay is reasonable as compared to market, potential employees seem to be increasingly difficult to locate.Retention is also a problem, probably due to physical demands.

May 2003

O&M O&M -- NonNon--Routine Corrective Routine Corrective MaintenanceMaintenance

Blade repairs, lightning damage & leading edge erosion.

Blade inspections and repairs are completed annually. About 25 lightning related repairs per year. Since commissioning, three blades have required

replacement due to lightning damage. Gearbox failures and subsequent replacement.

Gearbox life cycle appears to be 5-8 years.

Note: The repairs mentioned above require two cranes, a large 300 ton crane and a smaller 100 ton crane. Crane availability and expense are serious issues facing wind farm owners. Demand for crane service is currently outpacing availability.

May 2003

Performance MonitoringPerformance MonitoringPower Curve

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Power Curve

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Power curve for turbine with improper blade zero setting

Power curve for turbine with improper wind vane alignment

Reference

Actual Power

Solar

Solar Will Most Likely Be Integrated as Grid-Tied Panels on Rooftops, Instead of in Large Solar Farms

Solar electricity is still expensive compared to wind and grid prices, but the future looks good

Solar monitor (on display in the lobby) records solar radiation data

Distributed Energy

Distributed generation: Small power source located near the user

Concentrating Solar Power

Solar concentration allows tailored design approaches

Dish

TowerTrough

CPV

Photovoltaics

PV roofing shingles

PV panels

Mauna Lani Hotel in Hawaii

4 Times Square, New York City

HelioVolt Corp 200779

Global Photovoltaic Market Demand Through 2010 (MW)Global Photovoltaic Market Demand Through 2010 (MW)

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4,000

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7,000

Germany Rest of Europe Japan Rest of Asia United States Rest of World

2000 2005 2006 2007 2008 2009 20102001 2002 2003 2004

Source: Solar Today, 2007

Price decline of Modules

Residential PV System

Residential Pole Mount System

3.5kW Pole Mounted PV System

Austin Convention Center

188 Panels60 Watts

eachAmorphous

SiliconTwo Trace

Inverters

Airport - Taxi Staging Area

Electrical Properties of a Solar Cell

n-type

p-type

V+I

Photons

JunctionExternal circuit(e.g., battery,

lights)

36 Cells in Series Make a 12V-Class Panel (Voc 19V)

Two 12V-Class Panels in Series Make a 24V-Class Array (Voc 38V)

9 cells x 4 cells is acommon configuration

( )100524.034.5)( 1777.0 = VeVI

PV Station 13, Bright Sun, Dec. 6, 2002

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Isc

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Isc

Pmax at approx. 30V

Pmax 0.7 Voc Isc

The Maximum Power Point

PV Station 13, Bright Sun, Dec. 6, 2002

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P=0 at short circuit P=0 at open circuit

Pmax

On a good solar day in Austin, you get about 1kWh per square meter of solar panels

(corresponds to about 150W rated)

Where is the Sun?

Figure 4. Sun Zenith and Azimuth Angles

West

North(x axis)

Line perpendicular to horizontal plane

East(y axis)

Horizontal plane

Up (?z axis)

zenithsun

azimuthsun

Note because of magnetic declination, a compass in Austin points approximately 6 east of north.

Sun Moves from Summer to Winter

Solar Zenith versus Azimuth at Austin

22nd Day of Jun, Jly, Aug, Sep, Oct, Nov, Dec(Sun hrs/day. Jun=13.9,Jly=13.6,Aug=12.8,Sep=12.0,Oct=11.0,Nov=10.3,Dec=10.0)

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Sun Moves From Winter to Summer

Solar Zenith versus Azimuth at Austin22nd Day of Dec, Jan, Feb, Mar, Apr, May, Jun

(Sun hrs/day. Dec=10.0,Jan=10.3,Feb=11.0,Mar=12.0,Apr=12.8,May=13.6,Jun=13.9)

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Panel Orientation is Important

Best all-year tilt = Latitude

Best winter tilt = Latitude + 15

Best summer tilt = Latitude 15

tiltpanel

Line perpendicular to horizontal plane

tiltpanel

Horizontal plane

Figure 6. Panel Tilt Angle

Line perpendicular to panel surface

Edge of panel

Solar Radiation Monitors

Rotating Shadowband PyranometersMeasure GH and DH

NREL Sci Tec Two-Axis Tracker Measures DN, GH, and DH

GH (Global Horizontal W/m2): Sensor points straight up, sees entire sky, including sun disk

DH (Diffuse Horizontal W/m2): Once per minute, band quickly swings over, shadow falls on sensor. Then, sensor sees entire sky, less sun disk.

DN (Direct Normal W/m2): Tracking device points toward sun and sees only the sun disk

Computing Incident Power, cont.

panelincidentzenithsun

incident ADHGHDHP

+= )cos(

)cos()(

The incident solar radiation, in kW, on a panel surface is approximated by

About 14% is converted to electricity

Est. disk of sun component on sensor pointed toward sun

Measured sky on shadowed horizontal sensor (excludes

disk of sun)

Est. disk of sun component on panel surface

Multiply by surface area

Est. Watts on panel surface

The Clean Energy Future

Bio fuelsPlug-inH2

Zero Energy HomeDistributed Utility

Fossil Fuels

Solar

Nuclear

Wind

The Clean Energy Future

Plug-in Hybrid Power Train

Modest Electric Range Large Impact

Plugging In Improves Equivalent Fuel Economy

Comparative Co2 Emissions

Technology-Based Solutions:There is no single or simple answer.

Energy efficiency

Renewable energy

Nonpolluting transportation fuels

Transition to smart, resilient, distributed energy systems

Meet the Future. Today, Electrical and Computer Engineering Students are Eager to Learn About Renewable Energy and Conservation.

Renewable Energy is a perfect challenge for todays environmentally-minded students, both graduate and undergraduate