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Kevin Harris - ColumbiaGrid

Kevin Harris - ColumbiaGrid. DWG Concerns about Load Forecasting and Shapes & Maintenance Schedules Date: April 8, 2014. Concerns about loads. These are issues that make me ask question? What am I comparing: Actual 2010 monthly loads WECC preliminary 2024 forecast

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Kevin Harris - ColumbiaGrid

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  1. Kevin Harris - ColumbiaGrid DWG Concerns about Load Forecasting and Shapes & Maintenance Schedules Date: April 8, 2014

  2. Concerns about loads • These are issues that make me ask question? • What am I comparing: • Actual 2010 monthly loads • WECC preliminary 2024 forecast • Escalated 2022 forecast

  3. What to Look for (Annual Forecast) • Delta change in LF greater than or less than 6% in ten years • LF approaching 90% • Growth rate between neighboring that drastically different

  4. What to Look for (Monthly Forecast) • Monthly Load Shapes (Current & forecast year) • What to compare Monthly: Peak Demand (MW), Load (aMW), Load Factor (LF) • Spike or dip in one of the profiles • LF approaching 90% • Fundamental change in monthly shape: • Between neighbors load areas • Between actual and forecasted shape • Between weather normalized and forecasted shape

  5. Neighboring BA Load Growth 1 or 3 • Why would the forecasted load growth in LADWP be greater than SCE? • Considering LADWP service area is contained (an island) while SCE has potential for expansion

  6. Neighboring BA Load Growth 2 of 3 • Why would PSC growth at 0.3% while WACM at 3.2%? • 2011 IRP has 0.9% for PSC • Is PSC a contained area?

  7. Neighboring BA Load Growth 3 of 3 • Results in LF change of -10.6% • 66.7% in 2010 to 56.1% in 2024

  8. Monthly Shape #1 • Spike in Aug load relative to peak demand resulted in a spike in LF to 97%

  9. Monthly Shape #2 • Load Profile looks good • Peak profile not normalized • Issues in Jul/Aug and Q4 • Check peak demand profile?

  10. Monthly Shape #3 • Do I need to say anything?

  11. A Shift in Monthly Shape – Peak Demand • Why would TEP monthly peak shape be a month earlier than APS or SRP? • Note: Load shape are Ok APS vs. TEP SRP vs. TEP

  12. Identical Monthly Peak Shape • Why should the load shape for SCE and SDGE be identical? • SDGE has +80% of the population within ~15 miles of the coast • SCE is closer to 50/50 within ~15 miles of the coast

  13. Compare Monthly Peak Shape w/Temp • For SDGE (El Cajon): • Avg monthly temp exceeds 65 (CCD threshold) in May w/66.4 and Oct w/67.9 • Expect summer peak between Jul-Sep (Avg high temp exceeds 85) • Apr, May & Oct peak shape appears high compared to temperature shape • Temperature shape suggest load drops Oct through Dec Missing actual 2010 temp data Jan-Mar LF ~90% Warning: Avg monthly temp help with month-to-month directional change Full magnitude change requires hourly/daily temp vs. load profile

  14. Questions & Comments on Loads Kevin Harris ColumbiaGrid Harris@ColumbiaGrid.org (503) 943-4932

  15. Maintenance Scheduling • Concerns with LOLP derived maintenance schedules • What’s Dependable Capacity

  16. Issue with Calc Maintenance • When calc maintenance schedules most Production Cost Models (PCM) don’t properly take into account: • Energy limited supply: Hydro, contracts,… • Non-dispatchable supply: Wind, Solar, CG,... • Maintenance is limited to regions not user defined areas for maintenance.

  17. What is Dependable Capacity • Currently PCM use physical capacity when calc maintenance schedules using LOLP. • Dependable capacity should be used instead of physical capacity • Dependable Capacity is: • Available capacity during peak hour • For the traditional thermal units this is the winter/summer rating • Wind/Solar it’s the expected capacity during the peak hour with a 90+% probability of exceedance. Note: All supply is treated equally • Dispatchable fixed energy resources (Hydro, Contracts,..) • Dependable capacity is limited based on the monthly's energy ability to serve load. This is on a day-by-day basis for the month Dependable capacity does not limit operating reserve capability or ability to peak to max rating when needed by the system.

  18. Example Results - California Typically Hydro lines up with thermal and the maintenance patterns are similar Concern: LOLP method does not take into account the variability of rain and flood control which would trim Hydro maintenance in Jan-May • Winter/spring: You don’t’ know when you’ll have heavy run-off • Fall: You know Hydro generation will be low Note: This also applies to PNW

  19. Example Results - PNW Hydro and Thermal maintenance patterns are not similar They peak during different seasons 35,000 MW of Hydro generation with limited energy during the fall drops dependable capacity by 12,000 MW

  20. Method Used to Develop Charts: 1 of 2 • Supply: EIA-860 OP and UC units on-line Prior to end of 2013 • Maintenance areas are WECC Sub Regions: SPNW, CA, SW, RM • Setting Dependable capacity for: • Used scaled shape of CPUC NQC data • Wind (14 units) w/annual max of 6% • PV (3 units) w/annual max of 55% • ST-Sun (SEGS) w/annual max of 90%

  21. Method Used to Develop Charts: 2 of 2 • Dependable Hydro generation: • Monthly energy: Avg 2002-2013 monthly generation • Default assumptions for Run-of-River (ROR) • Assume ROR if avg summer/winter capacity is less than 30 MW • ROR Dependable capacity:= min of max capacity or monthly aMW * 1.15 • Default if dispatchable Hydro: Dispatchable Hydro capacity assumes daily energy is scheduled over 12 hour block:= 24/12:= 2.00 Dispatchable Hydro capacity:= aMW * 2.00 Dependable Hydro capacity:= min of [max capacity or Dispatchable Hydro capacity] • User can override default assumption

  22. Set Capacity Reserve • Apply reserve capacity: • Greater than System Avg Outage • A Min of two months having zero implied maintenance Implied Thermal Maint:= Dependable Cap – Peak Demand – Capacity Reserve Implied Hydro Maint:= Hydro De-Rate - Reserve Maintenance Factor:= Monthly Implied Maint/ Annual total Note: Imports are not included in this calc

  23. Missing: Variability in Peak Demand • Observation for summer peaks • The monthly standard deviation of daily peak temperature is high in the shoulder months vs. the peak months • LOLP does not consider variability in peak demand • Peak demand for determining maintenance my be different than normal shape forecast • Or Apply monthly load variability toreserve capacity

  24. Other Consideration • As a rule maintenance is not preformed the last ~ten days of the year. • People like to take Christmas off • Maintenance in the fall conflicts with deer season. • Staffing issue can limit seasonal maintenance schedules

  25. Desired Capability in PCM • User defined maintenance areas based on selected areas • Ability for the user to set monthly maintenance factors by maintenance areas • This allows user judgment to over come limits of LOLP scheduled maintenance method • A means to set dependable capacity by unit and/or class by month • Do we want a formula based calc for Hydro dependable capacity? • Ability to split Thermal and Hydro maintenance into maintenance factors

  26. Final Questions & Comments Kevin Harris ColumbiaGrid Harris@ColumbiaGrid.org (503) 943-4932

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