comparing load profiles: art or science?

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Comparing Load Profiles: Art or Science?. Roberta Laccetti National Grid 2005 AEIC Load Research Conference July 11, 2005. Question:. Do class load shapes vary by State? Utility? Supplier? Transmission Congestion Zone? Year?. Answer:. Yes. No. It depends on why youre asking. - PowerPoint PPT Presentation

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  • Comparing Load Profiles:Art or Science?Roberta LaccettiNational Grid2005 AEIC Load Research ConferenceJuly 11, 2005

  • Question:Do class load shapes vary byState?Utility?Supplier?Transmission Congestion Zone?Year?

  • Answer:Yes.No.It depends on why youre asking.

  • Real Questions:Can we use MA samples to represent NH rate classes in COS filings? Can we ignore one companys samples after merger? Do residential customer load shapes vary between utilities in MA? Do we need to update our load shapes every year?

  • Approaches to Comparing Load ShapesTraditional Load Research Statistics Visual Comparisons of GraphsNormalized or UnitizedAll, Average, or Specific Days Accounting for Errors in Estimated Loads Some Statistical Summaries

  • Question #1: Can we use MA samples to represent NH rate classes? Number of customers served in NH is less than 40,000.Cost of Load Research relative to revenues is high.MA is geographically close and good transfer methods can be used.ButRegulators are uniqueRate class definitions differAppliance saturation varies

  • Average Residential Load Shapes: MA/NH

  • Average Residential Load Shapes: MA/NH

  • Average Residential Load Shapes: MA/NH

  • Average Residential Load Shapes: MA/NH Peak Day with Error Bounds

  • Average Residential Load Shapes: MA/NH Some Summary StatisticsMean Bias Error:-0.02 Root Mean Squared Error:.11 Coefficient of Variation of the Root Mean Squared Error:.13

  • Question #1: Can we use MA samples to represent NH rate classes?

    Answer #1: No. Ordered by the commission.

  • Question #2: Can we ignore one companys samples after merger?EUA/NEES merger resulted in rate consolidation. Continuous and comprehensive samples existed in each company, doubling sample sizes. Metering differences required two reading systems. ButRegulators may want to evaluate impacts of consolidated rates on customers, by company.Using one companys samples to represent entire territory may produce biased results.

  • Medium C&I Load Shapes: NEES vs. EUA Unitized Average Day - August 2001

  • Unitized Average Day Load Shapes: NEES/Combined

    Percent Differences

  • Question #2: Can we ignore one companys samples after merger?

    Answer #2: No. NEES-only samples would produce biased estimates of merged company classes. Keep collecting data from both samples until new samples are implemented. Convince Meter Services group that the quicker they install new samples, the sooner they can stop using old collection system.

  • Question #3: Do residential customer load shapes vary between utilities in MA?

    Regulatory debate about Default Service pricing for customers with no competitive supply options. We recommend a single price for utility-provided service in each load zone. One Distribution Co. claimed differences in load profiles preclude a state-wide approach.

  • Comparison of Average Residential Load Shape:MA Utilities Normalized 2002

  • Question #3: Do residential customer load shapes vary between utilities in MA?

    Answer #3: No.Supports company recommendations on auction and pricing.

  • Question #4: Do we need to update our load shapes every year?Cost-cutting in Operations area has been severe.No regulatory requirement in NY.Wide range of practices in other companies.ButLoad shapes are used for commodity pricingLoad shapes support estimation of competitive supplier load and ICAP.

  • Comparison of 2003/2002 Load Shapes:Impacts on Pricing

    Transfer methods considered: Calendar Mapping Day-Type Mapping Weather Normalization

  • Comparison of 2003/2002 Load Shapes:ResultsLoad estimation for pricing and settlement:Calendar mapping:Load-weighted annual price = 1% below actualWeather model with 5 day-types and 4 seasons:Load-weighted annual price = .01% below actual Peak hour estimate (ICAP):Calendar mapping:Estimate of class demand = 1.9-29.7% below actualPrior years peak day (at peak hour):Estimate of class demand = 6.1% below to 20.4% above actual

  • Question #4: Do we need to update our load shapes every year?

    Answer #4: Maybe. National Grid NE practices.Risk of criticism by market players.Timing of next rate case.

  • SummaryThere are many different ways to compare class average load shapes. Conclusions about similarities and differences should be based on how the shape will be used. The answer may be, It depends

  • Extra Credit Question:What is causing spikes in Residential Class precision levels?

  • Clue

    MA= green, NH = blue

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