1. Resource Parameters Needed for LFC NATF WebEx Meeting 05/11/2010 Dave Maggio Operations Engineer, Supply Integration and Grid Applications

2. 2 Background LFC software currently includes multiple checks to confirm a generator is online and should be included in deployments and the reserve calculations. For this discussion we will focus only on the reserve calculations. –Status is online –Generation is NOT below a parameter driven percentage of HRL. (Unit Offline Limit) –When transitioning from an offline state to an online state; the generation is above Unit offline limit * (1+Unit online DB%/100) –Generation is above 95% of the telemetered LSL.

3. 3 Working solution The effects of most of these checks can be eliminated, resulting in only a check of unit status by setting two parameters to zero. SET: Unit Offline Limit (%) = 0 SET: Unit Online Dead band (%) =0 By setting these parameters to 0; the two of these checks are eliminated; leaving –Status is online –Generation is above 95% of the telemeter LSL.

4. 4 Unit Offline Limit and Unit Line Dead-Band These values will not be included in the request to Resource Entities This is contrary to what was stated at the 5/4/2010 NATF meeting Nodal Protocol 6.4.5(1) states that: –“ERCOT shall use the telemetered Resource Status for all applications requiring status of Resources during the Operating Hour, including SCED, Load Frequency Control (LFC), and Network Security Analysis processes.” The two parameters will be defaulted to “0” for all resources which will result in the telemetered resource and generation above 95% of LSL being used to confirm a unit is online.

5. 5 Background 2 Protocols section 8.1.1.4.1 requires that ERCOT calculate Generation Resource Energy Deployment Performance (GREDP) The GREDP calculation requires calculation of “Estimated Governor Response” = if (│Δfrequency│≥ frequency deviation deadband, (frequency bias * Δfrequency)*10,0) ERCOT is missing some components of this calculation. –Frequency Deviation deadband –Frequency Bias

6. 6 Frequency Deviation Dead-Band and Frequency Bias 8.1.1.4.1 (2) and (4) state that these resource specific parameters must be provided by the Resource Entity Frequency Deviation Dead-band is expressed in Hz Frequency Bias is expressed in MW/0.1Hz These values are used to calculate the estimated governor response Expected governor response is used to calculate expected MW output for each resource in LFC Expected governor response is also used for Nodal Protocol Section 8 reporting (GREDP/CLREDP) This includes Generation and Controllable Load Resources

7. 7 Frequency Deviation Dead-Band and Frequency Bias For a Combined Cycle train, a single value is calculated. Because of this, a single Dead-band and Bias pair is needed For a Jointly-Owned Resource, estimated governor response is calculated separately for each portion of the Resource –The Dead-Band will be set the same for each portion of the Resource –The Bias will need to be split based on the percent ownership The following will be used for defaults while ERCOT waits for the information to come in from the Resource Entities –0.036 Hz will be used for the frequency dead-band for all resources –5% droop will be used to calculate frequency bias (0 for Nuclear Resources and WGRs) –Based on 2.2.7(2) of the Nodal Operating Guides

8. 8 Collection of the Parameters These parameters can be collected through the RARF process –Use an addendum Will require approximately 2-3 months to complete Data initially collected separate from the RARF –Incorporate the addendum into the RARF form and database Add data elements to the RARF form Add data elements to the RARF database Reload all the new RARF forms and send to Resource Entities Most likely post Go-Live ERCOT will develop a business procedure to enter the values into the EMS system after a addendum/RARF has been submitted or updated Information should be provided by the Resource Entities and entered into ERCOT’s Nodal EMS system prior to the 48-hour LFC Test (July ‘10)