WECC Frequency Responsive Reserve criterion Proposal

1. WECC Frequency Responsive Reserve criterion Proposal Overview for Discussion David Lemmons WECC FRR Educational Workshop November 14, 2008 Portland, OR

2. Ali Amirali GBT Baj Agrawal AZPS Brian Tuck BPAT Clyde Loutan CISO David Lemmons PSCO Dennis Gerlach SRP John Stout Mariner Kim Clark WALC Phil Tice DGT Ray Vojdani WACM Rich Hydzik AVA Robert Johnson PSCO Shannon Black SMUD Steve Heidt AESO Todd Lietz PSEI Drafting Team Members

3. Goals for the Workshop • Explain “How we got here.” • Review posted draft • Explain Drafting Team rationale • Open Mic Q and A • Get feedback and productive comments both here and through the posting process

4. Background • RITF White Paper • Studied Frequency Response and recommended changes in the way WECC determines contingency reserve requirements • Current WECC criterion • Comments during WECC development process raised issues that could not be reasonably addressed by the Drafting Team • Drafting Team developed reporting criterion so questions could be answered • Data has been used to develop proposal • Issues still exist with data • In the near future, WECC will be asking for data clarification so further review can be made

5. Where We Are Today • Drafting Team conclusion • No reliability issue for today • Criterion Today • Prepares for tomorrow • Provides continued response going forward • Provides an early warning if response decreases • Requires performance without monetary sanctions • Standard Tomorrow? • Could morph into a Reliability Standard in the future.

6. Criterion vs. Standard • Requirements and Measures • The same • Enforcement • There are no NERC sanctioned fines • WECC has leverage

7. Requirement 1 • The Reliability Coordinator shall: • Communicate the total WECC FRR Requirement to all WECC BAs and RSGs. • Consideration • Is the RC the correct entity to do this? • If not – what Applicable Entity? • Is there a more effective methodology for determining the amount of FRR needed? • If so – we need detailed input

8. Requirement 2 • Each BA/RSG shall average 100% Primary Frequency Response during the measurement period. • Measurement period is 365 days or 5 events, whichever is greater. • Several questions are asked related to this requirement in the comment form.

9. Requirement 3 • Secondary Frequency Response is required to be sufficient, but not excessive. • Drafting Team wants to ensure transmission lines are not overloaded due to excessive response or lack of support. • Comments are solicited related to the levels chosen

10. Requirement 4 • Requires that BAs/RSGs provide listed data • At not more than a 6 second interval • Used to determine compliance and future study • Data included: • Time stamp, ACE, Actual Frequency, Scheduled Frequency, Frequency Bias, Scheduled and Actual Net Interchange, Actual Generation and Load, and certain Transmission Path Flows. • Consideration • Is this the appropriate data for this purpose?

11. M2 -Primary Frequency Response Measurement Baj Agrawal 0 to 30 seconds

12. Primary Frequency Response Topics • Amount Needed for Interconnection • BA’s Obligation • Adjustment to BA’s obligation • Response for an event • Average Response

13. Amount Needed for Interconnection • Based upon two largest generator outage at same power plant • Total Interconnection response must be equal to lost generation to arrest frequency

14. Amount Needed for Interconnection • Frequency will keep declining until the interconnection response equals lost generation • Point C is where Primary Frequency Response has just matched the amount of lost generation

15. Frequency Response Frequency (Hz) 60.050 60.025 A = 60.000 60.000 59.975 59.950 59.925 59.900 B = 59.874 59.875 59.850 59.825 C = 59.812 59.800 59.775 59.750 -30 -20 -10 0 10 20 30 40 50 60 Time (Seconds) Sample Event

16. Components of the Response • The increased MW output from the generators due to governor response • Reduction in load due to reduced frequency (frequency sensitivity of load)

17. Components of the Response • Change in losses due to change in flow pattern • All of the above components are included in the change in interchange measurement

18. BA’s Obligation • Equal weight given to load and generation • Primary Frequency Response Obligation= Max Gen Loss * (0.5 BA Gen + 0.5 BA Load) Total interconnection generation on-line

19. Example: • If: • Two largest generation outage = 2800 MW • Interconnection load = 100 GW • BA = 5 GW load + 5 GW generation • Then: • Unadjusted Primary Frequency Response Obligation = 2800*(0.5*5+0.5*5)/100=2800*.05=140 MW = 5% of the 2800 MW needed

20. Adjustment for Actual Frequency Primary Frequency Response Obligation is adjusted for actual frequency deviation at the minimum frequency point (Point C) AR=Frequency deviation at Point C/0.50 For example, if the actual frequency at point C is 59.75 Hz, then: AR= (60-59.75)/0.5=0.5 And the adjusted Primary Frequency Response Obligation= 140*0.5=70 MW

21. Min/Max Primary Frequency Response Obligation • AR has a minimum value of 0.30 corresponding to frequency of 59.85 • AR has a maximum value of 1.0 corresponding to Point C frequency of 59.5 Hz. • Thus for the above BA the minimum obligation would be 140*.30=42 MW • And maximum obligation would be 140 MW

22. Adjusted for Transferred Obligation • BA can: • Transfer its obligation to another BA (or) • Accept obligation from other BA by mutual agreement. • Example • In the above example, if BA X accepts another BA’s 50 MW obligation for the event then its total obligation for the example event would be: =140*AR+ Accepted obligation =140*.5+50 =120 MW • Note that the 50 MW obligation accepted is the value for that particular event and is the adjusted value. • The transferring BA’s obligation would reduce by 50 MW for this event.

23. Primary Frequency Response Duration • Time window • Starts at the beginning of the Frequency Response Measurement Event • Ends 30 seconds thereafter • Restated • Starts at “Point A” and ends 30 seconds thereafter • The credited response is the maximum value registered within this 30 seconds period

24. Primary Frequency Response Measurement Period • Why averaging? • The actual frequency response for a given event is going to vary depending on factors such as type of units on line and their operating mode, type of loads on-line etc. • What is averaged? • The BA’s response over the last 5 events or last 12 months, whichever is greater, will be averaged for the purpose of determining whether the BA met its obligation

25. M3 – Secondary Frequency Response MeasurementDennis Gerlach 31 seconds plus

26. Why ACE? • Change in interchange has many variables that are captured in ACE • Ramp • Dynamic schedules & others • Can have significant influence over this long period of time • ACE includes: • A bias component, • A measure of a BA’s required contribution to frequency restoration.

27. A Basic Example • Assume the following: • A loss of generation has occurred outside your BA • Your bias is set correctly • The frequency is below 60 HZ • Prior to the event your ACE was exactly at zero

28. A Basic Example • Post event - if your ACE is: • Negative by (10B * ∆F) • Then no contribution • Equal to zero • Then exactly the right contribution • Over zero • Then contribution more than required

29. Measurement in each period • How your contribution is scored • No contribution = zero • Contribution equal to required amount = 1.0 • Twice the required contribution = 2.0

30. Measurement in each period • If zero or below ACE before the event • Then measured against pre-disturbance ACE • If above zero pre-disturbance • Contribution is indexed to zero • For example • If pre-disturbance ACE is over zero by exactly the bias requirement, no addition response is required and you earn a score of 1.0

31. Total scoring for the event • Measurement period is once each scan • Event begins at 31 seconds • Continues to 59.9 Hz • but no longer than 15 minutes • Score is average response for each period • Required score between 0.5 and 2.0 • Exception • Additional upper limit to restrict very high response from variable bias entities

32. Open Mic Q and A

33. Questions? • Contact Drafting Team members • Include questions with your comments in the Criteria posting • Participate in the deliberations of the Drafting Team