BAL-001-TRE-1 Primary Frequency Response Update for Texas RE RSC October 3, 2012

SAR-003 Standard Drafting Team Name Company Sydney Niemeyer (Chair) NRG Energy Ananth Palani (Vice-Chair) Optim Energy Pamela Zdenek Infigen Energy Vann Weldon ERCOT Brenda Hampton Luminant Sandip Sharma ERCOT (Non-voting SME) BAL-001-TRE-1 RSC October 3, 2012

Requirements Overview Applies to BA, GO and GOP function Provides requirements for: Identifying Frequency Measureable Events (FME) Calculating the Primary Frequency Response (PFR) of each resource in the Region Calculating the Interconnection minimum Frequency Response Monitoring the actual Frequency Response of the Interconnection Setting Governor deadband and droop parameters Providing Primary Frequency Response performance requirements. Importantly, the standard narrows the governor deadband and requires the droop curve to begin at the edge of the deadband with no step function. BAL-001-TRE-1 RSC October 3, 2012

PFR Performance Measures Under this standard, two Primary Frequency Response performance measures are calculated: “initial” and “sustained.” The initial PFR performance (R9) measures the actual response compared to the expected response in the period from 20 to 52 seconds after an FME starts. The sustained PFR performance (R10) measures the best actual response from t(46) to t(60), compared to the expected response at t(46). BAL-001-TRE-1 RSC October 3, 2012

Primary Frequency Response Reference Document This Primary Frequency Response Reference Document is not considered to be a part of the regional standard. This document will be maintained by Texas RE and will be subject to modification as approved by the Texas RE Board of Directors, without being required to go through the formal Standard Development Process. This arrangement provides Regional flexibility in adjusting the technical details of the performance metric calculations. The PFR Reference Document includes flowcharts that detail the calculations BAL-001-TRE-1 RSC October 3, 2012

PFR Reference Document Revision Process A Revision Request may be submitted to the Texas RE Reliability Standards Manager The Reliability Standards Committee (RSC) will consider the request The revision request will be posted in accordance with RSC procedures The RSC shall discuss the revision request in a public meeting, and will accept and consider verbal and written comments pertaining to the request The RSC will make a recommendation to the Texas RE Board of Directors The Board may adopt the revision request, reject it, or adopt it with modifications Any approved revision to the Primary Frequency Response Reference Document shall be filed with NERC and FERC for informational purposes BAL-001-TRE-1 RSC October 3, 2012

Technical Document – Initial Flowchart Overview Read Deadband, Droop, HSL, Capacity and Actual Frequency Calculate Ramp Magnitude Calculate Expected Primary Frequency Response Calculate Actual Primary Frequency Response Calculate P.U. Primary Frequency Response Calculate P.U. Primary Frequency Response Rolling Average No Is Rolling Avg ≥ 0.75 Fail R9 Yes End Pass R9 BAL-001-TRE-1 RSC October 3, 2012

Based on events from June 2011 to June 2012. Field Trial Results 28 generating units were evaluated in the trial, which included 7 coal, 4 gas, 2 simple cycle combustion turbine, 5 wind, and 10 combined cycle units. Based on events from June 2011 to June 2012. No high-frequency events were evaluated. 8-event average was not possible with some units. These results use NEW R10 calculation. BAL-001-TRE-1 RSC October 3, 2012

Field Trial Results – Coal Units BAL-001-TRE-1 RSC October 3, 2012

Field Trial – Gas Units BAL-001-TRE-1 RSC October 3, 2012

Field Trial – Wind Units BAL-001-TRE-1 RSC October 3, 2012

Field Trial – Combined Cycle Units BAL-001-TRE-1 RSC October 3, 2012

Changes Made after Field Trial and Comments Changed Sustained Measure (R10) from average over several minutes to instantaneous at t(46). Too much happens during former averaging window. Added 2 MW limit to the 2% exception criteria. Applies to generators < 100 MW. Moved examples of “legitimate operating conditions that may support exclusion” from Measures to Requirements (R9 and R10). M7 re-written to focus on notice from GO to GOP of change in Governor status. Avoids concern about 24/7 proof issue. Changed deadband setting from 0.01666 to 0.017 Hz. Reformatted R2 to break into sub-requirements. Intend to deal with augmented capacity issue. Duct burners, etc. BAL-001-TRE-1 RSC October 3, 2012

Implementation Plan 12 months after Effective Date The BA must be compliant with Requirement R1 At least 50% of the GO’s generating units/generating facilities must be compliant with Requirement R6 (if >1 unit/facility) At least 50% of the GO’s generating units/generating facilities must be compliant with Requirement R7 (if >1 unit/facility) The GOP must be compliant with Requirement R8 18 months after Effective Date The BA must be compliant with Requirements R2, R3, R4, and R5 100% of the GO’s generating units/generating facilities must be compliant with Requirement R6 100% of the GO’s generating units/generating facilities must be compliant with Requirement R7 BAL-001-TRE-1 RSC October 3, 2012

Implementation Plan 24 months after Effective Date At least 50% of the GO’s generating units/generating facilities must be compliant with Requirement R9 (if >1 unit/facility) At least 50% of the GO’s generating units/generating facilities must be compliant with Requirement R10 (if >1 unit/facility) 30 months after Effective Date 100% of the GO’s generating units/generating facilities must be compliant with Requirement R9 100% of the GO’s generating units/generating facilities must be compliant with Requirement R10 BAL-001-TRE-1 RSC October 3, 2012

Drafting Team is finishing standard and related documents. Path Forward Drafting Team is finishing standard and related documents. Expect completion in November. (11/7 SDT Mtg.) Submit for RSC approval in November. Can do by e-mail or call a special meeting. Post for Review and Ballot in December – January. Avoid ballot during Holidays. RSC Approves ballot results. TRE Board approval. NERC/FERC process. BAL-001-TRE-1 RSC October 3, 2012

R9: Initial Response Performance - Steam Turbine BAL-001-TRE-1 RSC October 3, 2012

R10: Sustained Response Performance - Steam Turbine BAL-001-TRE-1 RSC October 3, 2012

R9: Initial Response Performance - Steam Turbine BAL-001-TRE-1 RSC October 3, 2012

R10: Sustained Response Performance - Steam Turbine BAL-001-TRE-1 RSC October 3, 2012

R9: Initial Response Performance - Steam Turbine BAL-001-TRE-1 RSC October 3, 2012

R10: Sustained Response Performance - Steam Turbine while Ramping up before and during event BAL-001-TRE-1 RSC October 3, 2012

R9: Initial Response Performance - Combustion Turbine with below standard performance BAL-001-TRE-1 RSC October 3, 2012

R10: Sustained Response Performance – Combustion Turbine with below standard performance BAL-001-TRE-1 RSC October 3, 2012