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Enron Mail |
There are several items worth noting regarding the ERCOT's methodology:
Regulation Reserve Requirements (RGRS). ERCOT has determined that 600 MW o= f=20 Reg up and down will be adequate for 95% of the hours during the year, if= =20 historic patterns hold and if balancing energy is deployed properly. Durin= g=20 what ERCOT considers to be "high stress" periods, they will increase their= =20 normal RGRS requirement by a multiple of 2-3. The initial start-up of the= =20 single control area will be considered "high stress" and ERCOT will purcha= se=20 2-3 what is necessary to cover the inexperience of the operators. This wil= l=20 be the practice until ERCOT is comfortable with the single control area (or= =20 until market participants complain about the high cost of A/S). The high= =20 stress option will remain available for the first year of operations. Non-Spinning Reserve Requirements (NSRS). ERCOT proposes to a methodology = of=20 purchasing NSRS only when projected risk of insufficiency is higher than=20 normal, or large amounts of spinning reserve are not projected to be=20 available online based on resource plans.. This boils down to where the=20 temperature is projected to be greater than 92 degrees, less than 32 degree= s=20 Fahrenheit or uncertain and when spinning reserves less than 4600 MW are=20 projected. Here is the process: 1. Review the weather forecast for the next day and see if it differs=20 significantly from the current day. 2. If the next day forecast is =01&similar=018 to the current day forecas= t, and=20 the current day forecast high temperature is <92, and the current day lo= w=20 temperature is greater than 32 degrees, and the current day generation plan= =20 shows <4600 MW of spinning reserve online all day long, and the current= =20 month is not April, May, or October, THEN no NSRS is considered to be=20 required all day for the next day. 3. Else: Purchase NSRS using the following: ? If the current month is April, May or October, then purchase NSRS in=20 amounts equal to the largest unit online for the hours projected within= =20 80% of peak hour. ? If today=01,s and tomorrow=01,s ERCOT high temperature is projected abo= ve 92=20 degrees, then purchase NSRS in amounts equal to the largest unit online= =20 for the hours projected warmer than 92 degrees. ? If tomorrow=01,s low temperature forecast is projected below 30 degrees= ,=20 then purchase NSRS in amounts equal to the largest unit online for the= =20 projected morning load pickup hours and hours projected within 80% of peak= =20 hour. Purchase amounts of NSRS equal to the largest unit online for hours in= =20 which the Day Ahead operator estimates spinning reserves online will dro= p=20 lower than 4600 MW. Replacement Reserve Requirements (RPRS). The requirement will be set at th= e=20 amount of RPRS required to resolve supply inadequacy, CSC, and OC (local)= =20 congestion simultaneously. There will be procurement of RPRS if the resour= ce=20 plans indicate capacity inadequacy based on the QSE scheduled load with th= e=20 ERCOT projected load. If the ERCOT projected load is greater than the QSE= =20 scheduled load and capacity available in the resource plan does not cover t= he=20 difference, then there is a capacity inadequacy problem. If the CSC flows= =20 based on the QSE schedules are greater than the limits, then the CSC proble= ms=20 are recorded. Then a transmission contingency analysis will be run to=20 identify OC constraints. If the flows are greater than the limits, the OC= =20 flow values are recorded. When there are insufficient RPRS bids for ERCOT = to=20 resolve its reliability and security concerns, ERCOT may choose to request= =20 OOM capacity or to use RMR units. ERCOT will use the scheduling pricing=20 dispatch (SPD) to determine which OOM and RMR units should be selected and= =20 when to discontinue OOM/RMR service. Balancing Energy Requirement. ERCOT's goal for balancing energy is (1) to= =20 use BES so that regulation service in either direction is not depleted, (2)= =20 to minimize net energy in regulation, and (3) to provide frequency control= =20 when frequency is high, especially during minimum load intervals. ERCOT wi= ll=20 use a two-step approach to calculate balancing energy service needs. Step= =20 one will be to clear the balancing energy service market resolving=20 load-generation balances and Zonal congestion (local congestion is ignored)= . =20 Step two is to determine the balance energy service needs to resolve local= =20 congestion as well as generation-load balance and zonal congestion. The= =20 desired result of step two is to minimize the cost of local congestion whic= h=20 will be an uplift to the market. Balancing Energy Down Bid Percentage Requirement. This will be used for=20 congestion management and frequency control (to correct for high frequency)= . =20 ERCOT will evaluate the export amount of each congestion management zone an= d=20 transmission transfer capability between CM Zones. If the export amount is= =20 greater than the calculated transfer capability of a CM Zone, then the=20 difference between these two values is the potential congested MW, or the= =20 total MW of DES Down bids needed for clearing Zonal Congestion. Also=20 sufficient down bid percentage requirement will be determined by ERCOT. =20 Market rules dictate that by 0600 of the day ahead QSEs will be notified of= =20 this percentage requirement for BES down bids by Congestion Zone. Responsive Reserve Requirement (RRS). The RRS requirement is set at 2300 M= W=20 for all hours under normal conditions. Interruptible responsive reserve=20 cannot exceed 25% of the QSE total requirement.=20 For the initial start-up period of the market, ERCOT will have the tendency= =20 to over buy ancillary services while the are "adjusting" to the single=20 control area. Thane Thomas Twiggs Enron Corp 1400 Smith Street Houston, Texas 77002 713-853-3199 Voice 713-408-4463 Mobile 713-646-8272 Fax 877-968-8967 Digital Pager or 8779688967@skytel.com ----- Forwarded by Thane Twiggs/ENRON_DEVELOPMENT on 04/10/2001 04:59 PM --= --- =09Thane Twiggs =0904/10/2001 03:42 PM =09=09=20 =09=09 To: Doug Gilbert-Smith/Corp/Enron@ENRON, Clint Dean/Corp/Enron@Enron= , Smith=20 L Day/HOU/ECT@ECT, Eric Saibi/Corp/Enron@ENRON, Mike Curry/Enron@EnronXGate= ,=20 Martin Lin/Contractor/Enron Communications@Enron Communications, Ron=20 McNamara/NA/Enron@Enron, Thane Twiggs/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT,= =20 Jean Ryall/NA/Enron@ENRON, Michelle Parks/Enron@EnronXGate, Christi L=20 Nicolay/HOU/ECT@ECT =09=09 cc:=20 =09=09 Subject: ERCOT Ancillary Services Methodology The attached file was large so I will provide the link to the ERCOT website= . =20 If you cannot down load and would like a hard copy, let me know.=20 http://www.ercot.com/currents.htm -- It is under Ancillary Services=20 Methodologies. Thane Thomas Twiggs Enron Corp 1400 Smith Street Houston, Texas 77002 713-853-3199 Voice 713-408-4463 Mobile 713-646-8272 Fax 877-968-8967 Digital Pager or 8779688967@skytel.com ----- Forwarded by Thane Twiggs/ENRON_DEVELOPMENT on 04/10/2001 03:38 PM --= --- =09Thane Twiggs =0904/10/2001 03:04 PM =09=09=20 =09=09 To: Doug Gilbert-Smith/Corp/Enron@ENRON, Clint Dean/Corp/Enron@Enron= , Smith=20 L Day/HOU/ECT@ECT, Eric Saibi/Corp/Enron@ENRON, Mike Curry/Enron@EnronXGate= ,=20 Martin Lin/Contractor/Enron Communications@Enron Communications, Ron=20 McNamara/NA/Enron@Enron, Thane Twiggs/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT,= =20 Jean Ryall/NA/Enron@ENRON, Michelle Parks/Enron@EnronXGate, Christi L=20 Nicolay/HOU/ECT@ECT =09=09 cc:=20 =09=09 Subject: ERCOT Ancillary Services Methodology Attached is the proposed ERCOT ISO methodology for determining A/S=20 Purchases. The methodologies will be presented to the ERCOT Board for=20 approval April 17, 2001. Thane Thomas Twiggs Enron Corp 1400 Smith Street Houston, Texas 77002 713-853-3199 Voice 713-408-4463 Mobile 713-646-8272 Fax 877-968-8967 Digital Pager or 8779688967@skytel.com
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