This Page Intentionally Blank TABLE OF CONTENTS 2.1 RESOURCE PLANNING BASICS....................................... 10 DEFINITIONS........................................................................... 10 EXAMPLES OF TRADITIONAL SUPPLY-SIDE RESOURCES............. 11 EXAMPLES OF RENEWABLE SUPPLY-SIDE RESOURCES.............. 13 PLANNING TOOLS ................................................................... 14 COMPUTER MODELS ............................................................... 17 2.2 INDUSTRY OVERVIEW....................................................... 19 ENVIRONMENTAL REGULATORY CHALLENGES ........................... 19 ELECTRICITY CONSUMPTION AND CO2 EMISSIONS..................... 24 FUEL ADEQUACY – NATURAL GAS............................................ 24 FUEL ADEQUACY - COAL ......................................................... 28 STORAGE RESOURCES............................................................ 29 FEDERAL PTC EXTENSION ...................................................... 35 ACCOUNTING CONSIDERATIONS FOR PPAS .............................. 36 REGIONAL AND NATIONAL TRANSMISSION INITIATIVES................ 41 2.3 PUBLIC SERVICE OVERVIEW........................................... 49 SERVICE TERRITORY............................................................... 49 EXISTING PUBLIC SERVICE GENERATION SUPPLY MIX ............... 50 OVERVIEW OF THE 2007 ERP ................................................. 51 2020 PUBLIC SERVICE GENERATION SUPPLY MIX ..................... 53 COLORADO TRANSMISSION PLANNING INITIATIVES..................... 54 2.4 EVALUATION OF EXISTING RESOURCES....................... 56 COMPANY OWNED RESOURCES ............................................... 56 PURCHASED POWER ............................................................... 57 WATER RESOURCES ............................................................... 60 DEMAND-SIDE MANAGEMENT PROGRAMS................................. 66 ATTACHMENT 2.4-1 OWNED GENERATION UNIT LOCATIONS..... 69 ATTACHMENT 2.4-2 OWNED GENERATION UNIT DESCRIPTIONS 70 ATTACHMENT 2.4-3 OWNED GENERATION AVAILABILITY .......... 72 ATTACHMENT 2.4-4 ESTIMATED REMAINING USEFUL LIFE........ 73 ATTACHMENT 2.4-5 CAPACITY FACTOR ESTIMATES................. 74 ATTACHMENT 2.4-6 PPA DURATION AND MODIFICATION TERMS75 ATTACHMENT 2.4-7 2010 WATER CONSUMPTION ................... 78 2.5 TRANSMISSION RESOURCES .......................................... 81 ELECTRIC TRANSMISSION SYSTEM ........................................... 81 TOT TRANSMISSION TRANSFER CAPABILITY LIMITATIONS .......... 83 SB07-100 NEW TRANSMISSION ADDITIONS .............................. 87 2011 Electric Resource Plan Volume 2 Technical Appendix Public Service Company of Colorado Page 2-1 TRANSMISSION ADDITIONS....................................................... 92 TRANSMISSION INJECTION CAPABILITY...................................... 93 TRANSMISSION SERVICE AGREEMENTS .................................... 95 COORDINATION AGREEMENTS.................................................. 97 2.6 ELECTRIC ENERGY AND DEMAND FORECASTS........... 98 INTRODUCTION ....................................................................... 98 ACTUAL AND FORECASTED DEMAND AND ENERGY................... 103 ENERGY AND DEMAND FORECASTS, 2011-2050 ..................... 104 FORECAST OVERVIEW........................................................... 113 FORECAST METHODOLOGIES ................................................. 114 VARIABILITY DUE TO WEATHER .............................................. 120 HIGH GROWTH FORECAST..................................................... 123 LOW GROWTH FORECAST ..................................................... 124 FORECAST ACCURACY .......................................................... 128 DESCRIPTION AND JUSTIFICATION .......................................... 136 COORDINATION LETTERS....................................................... 149 ATTACHMENT 2.6-1 COORDINATION LETTERS ....................... 150 2.7 HOURLY LOAD PROFILES .............................................. 155 INTRODUCTION ..................................................................... 155 2.8 PHASE 1 PLAN DEVELOPMENT AND MODELING DETAILS 216 STRATEGIST MODEL DESCRIPTION......................................... 216 ORGANIZATION OF SECTION 2.8............................................. 216 1. STRATEGIST MODELING - SET-UP AND FUNCTION .......... 217 2. MODELING THE ALTERNATIVE PLANS............................. 229 3. MODELING RESULTS.................................................... 242 ATTACHMENT 2.8-1 MODELING ASSUMPTIONS ...................... 263 ATTACHMENT 2.8-2 STRATEGIST MODELED EMISSIONS......... 277 ATTACHMENT 2.8-3 SENSITIVITY RESULTS ........................... 288 ATTACHMENT 2.8-4 LEC CALCULATIONS IN FIGURE 1.5-1 OF VOLUME 1 305 ATTACHMENT 2.8-5 ECONOMIC CARRYING CHARGE.............. 308 2.9 PHASE 2 BID EVALUATION............................................. 317 ALL-SOURCE RFP RELEASE AND INITIAL BID DUE DILIGENCE .. 319 INITIAL BID ECONOMIC ANALYSIS AND BID SCREENING............. 321 ASSESSMENT OF ARAPAHOE 4 AND CHEROKEE 4 ON GAS........ 325 SELECTION OF BIDS FOR COMPUTER MODELING ..................... 327 COMPUTER MODELING AND PORTFOLIO DEVELOPMENT ........... 328 WINTER GENERATION ADEQUACY OF PORTFOLIOS .................. 333 SENSITIVITY ANALYSES OF PORTFOLIOS ................................. 333 ATTACHMENT 2.9-1 WINTER GENERATION ADEQUACY STUDY.. 334 2.10 RESERVE MARGIN SUPPORT – LOLP STUDY.............. 337 2011 Electric Resource Plan Volume 2 Technical Appendix Public Service Company of Colorado Page 2-2 2.11 LOAD AND RESOURCE TABLE ...................................... 338 ATTACHMENT 2.11-1 RAP L&R........................................... 339 2.12 COAL PLANT CYCLING COST STUDY ........................... 340 2.13 WIND INTEGRATION COST STUDY ................................ 341 2.14 2011 WIND LIMIT STUDY ................................................. 342 2.15 CHEROKEE 4 REPLACEMENT ALTERNATIVES STUDY343 2.16 10-12 YEAR TRANSMISSION PLANNING STUDY .......... 344 2011 Electric Resource Plan Volume 2 Technical Appendix Public Service Company of Colorado Page 2-3 LIST OF TABLES Table 2.1-1 General Cost Structure of Thermal Resources________________12 Table 2.1-2 Simple Load & Resources Table___________________________15 Table 2.2-1 Gas Resource Review Summary __________________________25 Table 2.2-2 Evaluation of PRB Coal Resource _________________________29 Table 2.3-1 Resources Added Through 2007 ERP (MW) _________________52 Table 2.4-1 Public Service Owned Generation Facilities (MW) _____________56 Table 2.4-2 Public Service Owned Generation Facilities __________________57 Table 2.4-3 PPA Generation Resource (MW) __________________________57 Table 2.4-4 PPA Summer Capacity __________________________________58 Table 2.4-5 PPA Summer Capacity - Under 10 MW _____________________59 Table 2.4-6 Purchase Power Capacity by Fuel Type (2012) _______________60 Table 2.4-7 Summary of Public Service Water Rights Portfolio_____________63 Table 2.4-8 Summary of Public Service Water Contract Portfolio ___________63 Table 2.4-9 Energy Savings Goals Used in 2011 ERP ___________________66 Table 2.5-1 TOT Transmission Transfer Capability Limitations (2011) _______85 Table 2.5-2 SB07-100 Projects Likely to be In-Service During the RAP ______90 Table 2.5-3 Injection Capabilities ____________________________________93 Table 2.5-4 Wheeling Provided under Existing PPAs ____________________96 Table 2.6-1 Actual and Forecasted Summer Native Load Peak Demand ____101 Table 2.6-2 Actual and Forecasted Annual Native Load Energy Sales ______102 Table 2.6-3 Actual and Forecasted Summer Peak Demand and Annual Energy 104 Table 2.6-4 Base Case: Energy/Coincident Summer and Winter Demand ___105 Table 2.6-5A Base Case: Energy/Coincident Summer Demand/Winter Peak Demand by Major Customer Class ____________________________________106 Table 2.6-5B Base Case: Energy/Coincident Summer Demand/Winter Peak Demand by Major Customer Class ____________________________________107 Table 2.6-6 Base Case: Energy and Capacity Sales to Other Utilities_______108 Table 2.6-7 Base Case: Intra-Utility Energy and Capacity Use ____________109 Table 2.6-8A Base Case: Losses by Major Customer Class _______________110 Table 2.6-8B Base Case: Losses by Major Customer Class _______________111 Table 2.6-9 Base Case: Energy and Peak Demand DSM Savings _________112 Table 2.6-10 Actual and Forecasted Summer Peak Demand ______________113 Table 2.6-11 Actual and Forecasted Annual Energy Sales ________________114 Table 2.6-12 Native Peak Demand Weather Variability ___________________121 Table 2.6-13 Annual Native Energy Sales Weather Variability _____________122 Table 2.6-14 Base Case, High, and Low Sales of Energy _________________126 Table 2.6-15 Base Case, High and Low Coincident Summer and Winter Peak Demand 127 Table 2.6-16 Native Energy Sales Forecast Comparison (GWh)____________129 Table 2.6-17 Forecast Sales less Actual Sales (GWh) ___________________129 Table 2.6-18 Coincident Summer Demand Forecast Comparison (MW)______130 Table 2.6-19 Forecast Demand less Actual Summer Native Peak Demand (MW) 130 2011 Electric Resource Plan Volume 2 Technical Appendix Public Service Company of Colorado Page 2-4 Table 2.6-20 Weather Normalized Coincident Summer Demand Forecast Comparison (MW) _________________________________________________131 Table 2.6-21 Forecast Demand less Actual Summer Demand (MW) ________131 Table 2.6-22 Coincident