Wind Generation: Contribution to Capacity Adequacy

1
Wind GenerationContribution to Capacity
Adequacy Reflecting Wind Integration Needs

• Mary Johannis/Ben Kujala, BPA
• PNW Resource Adequacy Forums
• Technical Committee Meeting
• October 16, 2009

2
Outline

• Wind Capacitys Contribution to Resource Adequacy
• Methods
• Councils Annual Resource Adequacy Assessment
  possible change to 5 Placeholder Value
• Need for Flexible Resources to integrate Variable
  Generation
• Examples of increased need and/or changed
  operations
• How to incorporate Need for Flexible Resources
  into Councils Annual Resource Adequacy
  Assessment?

3
Wind Forums

• NERC Joint Integration of Variable Generation
  Task Force (IVGTF) Resources Issues
  Subcommittee (RIS) Task 1.2 (Capacity Value) and
  Task 1.4 (Flexible Resources to integrate
  Variable Generation) Teams
• IVGTF Report http//www.nerc.com/docs/pc/ivgtf/IV
  GTF_Report_041609.pdf
• WECC Variable Generation Subcommittee (VGS)
  Planning Work Group
• Northwest PNW Resource Adequacy Forum/NW Wind
  Integration Forum

4
Wind Capacity Value Methods

• Effective Load Carrying Capability (ELCC)
  approach
• Evaluate effective wind capacity contribution
  based on LOLP studies with and without wind
  generation same target
• Need sufficient wind generation data to simulate
  full range of generation under various
  conditions, especially if wind and loads
  correlated at times
• Need realistic depiction of combined
  uncertainties
• Contribution of variable generation to system
  capacity during high-risk hours using historical
  data
• Investigate contribution of wind capacity during
  heat wave and cold snap events in PNW because of
  evidence of statistical relationship between lack
  of wind generation when it gets very hot or very
  cold
• Correlation between resource contribution and the
  resource mix by system (e.g. what is appropriate
  for a hydro based system)
• Wind may contribute more in energy-limited system
  if certain amount of wind generation can be
  counted upon during drought

5
Counting Wind toward Capacity Adequacy in the
Northwest

• Current Capacity Value 5 Placeholder based on
  preliminary BPA analysis
• Resource Adequacy Forums Efforts to Create
  Long-term Wind Generation Records for use in
  GENESYS
• Backcasting (unsuccessful)
• Synthetic Temperature-Correlated Wind Generation
  (presented at July Meeting)

6
Counting Wind toward Capacity Adequacy in the
Northwest
January 2009 Cold Snap
7
Simulated Wind Generation Historic Cold Snaps
8
Simulated Wind Generation Historic Heat Waves
9
Observed WindRegional Load Duration

• Treating the wind as negative load changes the
  duration curve.
• Minimum distance between the two curves is about
  1.6 of the nameplate.
• 99.5 of the hours have a 6.8 of the nameplate
  or more contribution of wind toward reducing
  the load durations.

10
NW Wind Capacity Value using ELCC Approach

• Difference between the percentiles of the load
  durations show us
• Between the 10th and 90th percentiles the
  contribution of the wind fleet was fairly flat
  with a slight trend of more energy during the
  lower loads.
• During the highest observed loads the difference
  is minimal.

11
NW Wind Capacity Value using High Risk Hours
Approach

• Alternately looking at the differences between
  the six peak hours with and without wind yields
• A minimum difference of zero.
• 97 of the time we could count on roughly 3
  hundredths of one percent of the nameplate in
  aMW.
• You have to go to 91 of the time before you get
  to a contribution of 1 of the nameplate in
  aMW.

12
Need for Flexible Resources

• CALIFORNIA EXAMPLE 1/
• 2007 CAISO 2007 Study concluded 20 RPS
  achievable without new flexible resources
• Nexant Study? A minimum of 2,250 MW of new
  quick-start and load following resources required
  in the state to meet operating requirements at
  33 RPS
• Morning and evening ramping needs increased
  significantly with higher levels of renewables (
  14,000 MW of wind and solar PV)

1/ From 9/24/09 Defining the Need for LA Basin
and Dispatchable Resources by Mark Minick, SCE
13
Need for Flexible Resources

• BPA Rate Case Example
• Significant Growth of Wind Reserves with High
  Penetration of Wind in BPA BA
• Results in Changed Operation of Federal Hydro
  System

14
Need for Flexible Resources
BPA Rate Case Example Wind Reserves Regulating
Following Imbalance
15
Reflecting Flexible Resource Need in Adequacy
Assessments

• Flexible Resource Sufficiency Metric
• How to Model in Probabilistic Studies
• Count miss in reserves requirements as a Loss of
  Load Event?
• Allocate part of resource capacity for reserves?