Power Supply Adequacy Assessment Model/Methodology Review

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Power Supply Adequacy AssessmentModel/Methodology
Review

• Steering Subcommittee Meeting
  January 29, 2010

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Outline

• Model Validation
• Benchmarking Process
• Sample Historical vs. Simulated Dispatch
• Methodology Review
• Current Adequacy Metric LOLP
• The Problem with LOLP
• LOLP Subcommittee Suggestions
• Next Steps

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Model Validation

• HYDSIM vs. actual monthly generation
• GENESYS vs. HYDSIM hydro generation output
• Hydro peaking calibration
• Trapezoidal Model/HOSS/Capacity Survey
• Check random variable distributions
• Water, wind, forced outage, load/temperature
• Simulated thermal dispatch vs. historical
  dispatch
• Simulated hydro dispatch vs. historical dispatch
• Simulated dispatch vs. schedulers perspective

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• Sample Comparison of Historical vs. Simulated
  Hydro Dispatch
• Hourly hydro dispatch is highly dependent on
  hourly load shape
• Historical and Genesys hydro load following is
  consistent
• Illustrative only based on old data and FW
  constraints

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Methodology ReviewCurrent Adequacy MetricLOLP
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GENESYS Simulation
Illustrative Example Only
Cold
Hydro Limited
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Curtailment Events(Peaking problems and energy
shortages)
Each event has a peak and duration.
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What do we Count?

• Ideally, we count significant events (those
  that we want to avoid)
• Energy threshold (or contingency resource) is
  1,200 MW for one day or 28,800 MW-hours from
  Dec-Mar
• Capacity threshold (or contingency resource) is
  3,000 MW in any hour from Dec-Mar and from Jun-Sep

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Curtailment Events(non-events not shown)
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Loss of Load Probability
Simulated 300 winters (December through March)
Out of 300 winters, 15 had an average curtailment
greater than 10 MW-seasons, which means that the
Winter Loss of Load Probability (LOLP) 15/300
5 percent
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Energy LOLP(Sum of Curtailed Energy Dec-Mar)
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The Problem with LOLP
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Potential Problem with LOLPSame LOLP Bigger
Magnitude
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Potential Problem with LOLPLower LOLP Bigger
Magnitude
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LOLP Subcommittee Reportand Recommendations
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LOLP Subcommittee Report

• Clearly define all reserve requirements
• Operating reserves
• Planning reserves
• Wind integration reserves
• Determine which reserve curtailments count toward
  LOLP
• Add temperature-correlated wind as a random
  variable
• Decouple temperature and water condition
• Define a contingency resource for each month of
  the year instead of defining threshold events
• Record curtailment events across all months of
  the year
• Consider using other adequacy metrics
• Continue to assess climate change impacts

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LOLP Review Status

• Reserves
• Work being done by PNUCC committee
• Temperature-correlated wind
• BPA working on a test data set
• Decouple temp and water
• Done
• Contingency resource
• Work needs to be assigned
• Annual metric
• Not yet started
• Other metrics
• BPA draft methodology
• PSRI review
• Climate change
• Ongoing

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Next Steps
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Possible Modifications to the Current Method

• Replace LOLP with an alternative metric
• Use LOLP in conjunction with an alternative
  adequacy metric
• Use LOLP in conjunction with the magnitude of the
  most severe event (or an average of the worst 10
  of events)

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Examples of Other Adequacy Metrics

• LOLE loss of load expectation ()
• Number of hours with curtailment divided by the
  total number of hours simulated
• Can be more intuitive, i.e. 99.5 reliable
• Does not address magnitude
• EUE expected unserved energy (MW-hr)
• Average amount of unserved energy per year
• Lacks specific information about severe events

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Work Plan

• PSRI review complete by early 2010
• Benchmark GENESYS by early 2010
• Tech Committee propose new metric and threshold
  by April of 2010
• Use new metric to assess 3 and 5 year adequacy by
  June 2010