Public Service CompanyPublic Service Companyof Colorado Plansof Colorado Plans

Tim TaylorTim TaylorPresident and CEOPresident and CEOPublic Service Company of Colorado,Public Service Company of Colorado,an Xcel Energy Companyan Xcel Energy Company

New York Analyst MeetingNew York Analyst MeetingDecember 5, 2007December 5, 2007

Safe HarborSafe Harbor

This material includes forwardThis material includes forward--looking statements that are subject to looking statements that are subject to certain risks, uncertainties and assumptions. Such forwardcertain risks, uncertainties and assumptions. Such forward--looking looking statements include projected earnings, cash flows, capital statements include projected earnings, cash flows, capital expenditures and other statements and are identified in this docexpenditures and other statements and are identified in this document ument by the words by the words ““anticipate,anticipate,”” ““estimate,estimate,”” ““expect,expect,”” ““projected,projected,””““objective,objective,”” ““outlook,outlook,”” ““possible,possible,”” ““potentialpotential”” and similar and similar expressions. Actual results may vary materially. Factors that expressions. Actual results may vary materially. Factors that could could cause actual results to differ materially include, but are not lcause actual results to differ materially include, but are not limited to: imited to: general economic conditions, including the availability of credigeneral economic conditions, including the availability of credit, t, actions of rating agencies and their impact on capital expendituactions of rating agencies and their impact on capital expenditures; res; business conditions in the energy industry; competitive factors;business conditions in the energy industry; competitive factors;unusual weather; effects of geopolitical events, including war aunusual weather; effects of geopolitical events, including war and acts nd acts of terrorism; changes in federal or state legislation; regulatioof terrorism; changes in federal or state legislation; regulation; actions n; actions of accounting regulatory bodies; the higher degree of risk assocof accounting regulatory bodies; the higher degree of risk associated iated with Xcel Energywith Xcel Energy’’s nonregulated businesses compared withs nonregulated businesses compared withXcel EnergyXcel Energy’’s regulated business; and other risk factors listed from s regulated business; and other risk factors listed from time to time by Xcel Energy in reports filed with the SEC, inclutime to time by Xcel Energy in reports filed with the SEC, including ding Exhibit 99.01 to Xcel EnergyExhibit 99.01 to Xcel Energy’’s report on Form 10s report on Form 10--K for year 2006.K for year 2006.

Public Service Company of ColoradoPublic Service Company of Colorado

2006 FinancialsEarnings Cont. Op $221 millionAssets $8,363 millionGAAP ROE 7.8%Equity Ratio 56.5%

2006 Owned GenerationCoal 2,617 MWGas 855 MWRenewable 242 MWWind 27 MW

2006 Retail Sales(Thousands of MWh / MMBtu)Electric 27,198Gas 125,123

ColoradoColorado

2006 Customers2006 CustomersElectricElectric 1,320,0001,320,000GasGas 1,260,0001,260,000

2006 Rate Base and ROE2006 Rate Base and ROE

Colorado ElectricColorado Electric $3,292$3,292 7.7%7.7%Colorado GasColorado Gas 1,1061,106 7.87.8WholesaleWholesale 418418 Not ReportedNot ReportedTotal Rate BaseTotal Rate Base $4,816$4,816

WeatherNormalized

Rate Base Earned ROE

WeatherWeatherNormalized Normalized

Rate BaseRate Base Earned ROEEarned ROE

Dollars in millionsDollars in millions

Regulated Equity Ratio = 60.3%Regulated Equity Ratio = 60.3%

Environmental PolicyEnvironmental Policy

StateState

Renewable Renewable Portfolio Portfolio

Standards Standards

DemandDemand--Side Side Management Management (annual GWh (annual GWh

savings)savings)Carbon Carbon

ReductionReduction

ColoradoColorado 20% by 2020 20% by 2020 ** 0.35%0.35% N/AN/A

* * Renewable Bill TimelineRenewable Bill Timeline5% by 20085% by 2008

10% by 201110% by 201115% by 201515% by 201520% by 202020% by 2020

Renewable Bill Provides:Renewable Bill Provides:Opportunity to own 25%Opportunity to own 25%of incremental windof incremental wind50% if ownership creates 50% if ownership creates economic development economic development benefitsbenefits

Current PositionCurrent Position

Wind capacityWind capacity 1,084 MW 1,084 MW

Wind in WindSourceWind in WindSource Over 255 GWh Over 255 GWh

Photovoltaic solar energyPhotovoltaic solar energy 8 MW8 MW

CustomerCustomer--sited photovoltaicsited photovoltaiccapacity in SolarRewardscapacity in SolarRewards 9 MW 9 MW

DSM electric sales reductionDSM electric sales reduction 0.7%0.7%—— Doubles DSM Commitment Doubles DSM Commitment

Resource Planning ProcessResource Planning Process

Last resource plan filed April 2004Last resource plan filed April 2004

Legislation modified process Legislation modified process

Three resource portfolio scenarios modeled Three resource portfolio scenarios modeled and optimizedand optimized

Costs and benefits of each scenario reviewed Costs and benefits of each scenario reviewed for the 2008for the 2008––2015 time period2015 time period

Preferred resource plan selected and submitted Preferred resource plan selected and submitted to the PUC on November 15, 2007to the PUC on November 15, 2007

Commission approval in 7 monthsCommission approval in 7 months

Colorado Resource PlanColorado Resource Plan

WindWind 800800Central SolarCentral Solar 225225CustomerCustomer--sitedsitedSolar Solar 29 29 DSMDSM 360360Gas GenerationGas Generation 980980BiomassBiomass 44RetirementsRetirements 340340

MWMW

WindWind SolarSolar DSMDSMEnergy SourcesEnergy Sources

1,084 MW1,084 MW

1,884 MW1,884 MW

17 MW17 MW

271 MW271 MW

147 GWh147 GWh

1,618 GWh1,618 GWh

20072007 20152015

Colorado Resource Plan Impact Colorado Resource Plan Impact

System Energy Mix System Energy Mix 20072007

CoalCoal64%64%

Gas Gas 27%27%

Wind 3%Wind 3%Hydro 1%Hydro 1%Econ 5%Econ 5%

System Energy MixSystem Energy Mix20152015

CoalCoal62%62%

Gas Gas 16%16%

WindWind15%15%

Hydro 0.8%Hydro 0.8%

Econ 4%Econ 4%

Biomass 0.2%Biomass 0.2%Solar 2%Solar 2%

Acquisition PlanAcquisition Plan

Acquire resources through 2015 by staged/targeted Acquire resources through 2015 by staged/targeted acquisitions; defer 2016 and beyond to future plansacquisitions; defer 2016 and beyond to future plans

Build new natural gasBuild new natural gas--fired combined cycle at Arapahoefired combined cycle at Arapahoe

Target 50% wind ownership through legislative set asideTarget 50% wind ownership through legislative set aside—— Acquire through BuildAcquire through Build--Transfer/PPA RFPTransfer/PPA RFP

25 MW solar in 2011 through PPA RFP25 MW solar in 2011 through PPA RFP

CustomerCustomer--sited solar projects through rebates and bidssited solar projects through rebates and bids

Own future generic thermal and solar thermal through Own future generic thermal and solar thermal through Reverse Auction/Build TransferReverse Auction/Build Transfer

Recovery on Capital ExpendituresRecovery on Capital Expenditures

0

200

400

600

800

1,000

1,200

2007 2008 2009 2010 2011

Traditional Enhanced Recovery

Dollars in millionsDollars in millions

Depreciation

$850$850

$650$650 $680$680$750$750

$945$945

Colorado Recovery MechanismsColorado Recovery Mechanisms

Ability to file either historic or forecast test yearAbility to file either historic or forecast test yearPurchased capacity cost adjustmentPurchased capacity cost adjustmentComanche 3 Comanche 3 –– forward CWIP via general rate caseforward CWIP via general rate caseTransmission riderTransmission riderRenewable Energy riderRenewable Energy riderIGCC rider (if there is an approved project)IGCC rider (if there is an approved project)DemandDemand--Side Management Cost Adjustment riderSide Management Cost Adjustment riderAir Quality Improvement riderAir Quality Improvement riderEnergy Cost adjustmentEnergy Cost adjustmentGas Cost adjustmentGas Cost adjustmentPartial decoupling on retail natural gasPartial decoupling on retail natural gas

Key PrioritiesKey Priorities

Achieve favorable regulatory treatmentAchieve favorable regulatory treatment—— Forecast test yearForecast test year—— Implement cost recovery ridersImplement cost recovery riders

Achieve carbon reduction goals, while increasing Achieve carbon reduction goals, while increasing companycompany--owned generationowned generation—— DemandDemand--Side ManagementSide Management—— Colorado Resource PlanColorado Resource Plan

—— 10% reduction by 2017; 20% by 202010% reduction by 2017; 20% by 2020

Strengthen people and talent managementStrengthen people and talent management

Strengthen transmission and distribution Strengthen transmission and distribution infrastructureinfrastructure

Positioned for SuccessPositioned for Success

High customer satisfactionHigh customer satisfactionCompetitive advantages through geographyCompetitive advantages through geography—— WindWind—— SolarSolarPartnering with key stakeholdersPartnering with key stakeholdersConstructive regulatory recovery mechanisms Constructive regulatory recovery mechanisms Resource plans deliver carbon reductionResource plans deliver carbon reduction—— 10% reduction from 2005 levels by 201710% reduction from 2005 levels by 2017—— 2009 plan to deliver 20% reduction by 20202009 plan to deliver 20% reduction by 2020Able to achieve plan at reasonable cost to customersAble to achieve plan at reasonable cost to customers

Environmentalist CommentsEnvironmentalist Comments

““It is one of the most significant resource plans being submittedIt is one of the most significant resource plans being submittedby any utility anywhere in the country. It gets us on the path by any utility anywhere in the country. It gets us on the path to to reducing carbon emissions. It provides a significant boostreducing carbon emissions. It provides a significant boostto the new energy economy. And it will help protect ratepayers.to the new energy economy. And it will help protect ratepayers.””Matt Baker Matt Baker -- Director, Environment ColoradoDirector, Environment Colorado

““In the fine tradition of ColoradoIn the fine tradition of Colorado’’s pioneers, Xcel Energy is s pioneers, Xcel Energy is charting the innovative and costcharting the innovative and cost--effective path forward to cut effective path forward to cut globalglobal--warming pollution, protect human health and propel warming pollution, protect human health and propel ColoradoColorado’’s clean energy economy.s clean energy economy.””Vickie Patton Vickie Patton –– Deputy General Counsel, Environmental DefenseDeputy General Counsel, Environmental Defense

““ItIt’’s the only Western utility to put forth a plan to cut its carbons the only Western utility to put forth a plan to cut its carbon--dioxide emissions. Itdioxide emissions. It’’s precedent setting. It should be a models precedent setting. It should be a modelfor other utilities.for other utilities.””John Nielsen John Nielsen –– Energy Project Director, Western Resource AdvocatesEnergy Project Director, Western Resource Advocates