Exhibit No.5
ATC/TTC CALCULATIONS AND METHODOLOGY STATEMENTSFROM ISO-NEAND PJM
ISO-New England - TTC/TRMIATC Document
Total Transmission Capability (TTC),
Transmission Reliability Margin (TR1VI), andAvailable Transmission Capability (ATC)
Introduction
This documentincludesthe following information:
• Basic explanationsof TTC, ATC, andTRM
• List ofNEPOOLinterfacesandforecast/postingresponsibilities
• Methodsof determiningTTC andTRM for eachinterface
• Informationaboutthepostingof TTC andATC valuesfor theNEPOOLinterfaces,including the timeframesandfrequencyofupdates
Basic Conceptsand Definitions
Total Transfer Capability (TTC)
NERC Definition The TotalTransferCapability(TTC) for aninterfaceis thebestengineeringestimateofthe total amountof electricpowerthatcanbetransferredoverthe interfacein areliablemannerin agiventime-frame.
Basisfor TTC TTCs forNEPOOLinterfacesareforecastby the ISO basedonthermal,voltage,orstability limitationsoftheties thatcomprisetheinterface. Powerflow analysisis usedto ensurethatphysicallimitswill not beviolatedfor crediblecontingencies.
FutureForecasts The TTC forecastfor periodsbeyond35 daysout is basedon seasonaloperatingstudiesthattakeinto accountanticipatedpeakloadsandgeneratormaintenanceschedules.
Within 35 days,abaseTTC is calculatedfrom historical“all linesin” datathattakesinto accountseasonalloaddistributions. The baseTTC is adjusteddaily into aforecastvaluethat accountsfor:• forecastloads• actualandscheduledtransmissionandgeneratoroutagesin
NEPOOLandneighboringsystems
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• changesin facility ratings• anticipatedloading of generators• anticipatedinter-Areaschedulesusedfor daily andweekly
securityanalysis.
Variationsacross Factorsusedin calculatingTTC for eachof theNEPOOLinterfacesinterfaces vary. Briefdescriptionsofthesemethodsaregiven in Section4.
ISO/Transmission TheISO calculatesthe forecastTTC fortheNEPOOL interfacesonProvider behalfof the transmissionproviderswithin NewEngland.Responsibility
Individual TransmissionProvidersusethe forecastTTCs accordingtotheir OASISpostingrequirements.
TransmissionReliability Margin (TRM)
Definition The TransmissionReliability Margin (TRM) is the portionofTTCthat cannotbeusedfor reservationof firm transmissionservicebecauseofuncertaintiesin systemoperation.ISONew Englandusesthe TRM to minimize theneedto curtail firm transmissionservice.
TheTRM is availablefor reservationofnon-firmtransmissionservice.Note thatwhenTRM = TTC, no firm transmissionreservationscanbemadeon the tie. Non-firm reservationscanbemadeup to the valueof TTC.
Variability of TRM TheTRMs areinterface-dependent,direction-specificandtime-dependent.Methodsusedto determineTRM vary for eachof theNEPOOLinterfacesaredescribedin Section4.
ISO/Transmission TheISO calculatestheforecastTRM for theNEPOOLinterfacesonProvider behalfof the transmissionproviderswithin New England.Responsibility
Individual TransmissionProvidersusethe forecastTRMs accordingto theirOASISpostingrequirements.
Available Transfer Capability (ATC)
Definition Firm Available TransferCapability(Firm ATC) for an interfaceis theof capabilityfor firm transmissionreservationsthatremainsafterFirm ATC allowing for existingfirm commitmentsandthe TRM.
Mathematically,Firm ATC is calculatedusing the equation:
Firm ATC = TTC — TRM — Existing Firm Commitments*.
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* Existing Firm Commitments consistof, Firm transmission
requestsin the following status,Confirmed,AcceptedandStudy.
Definition Non-Firm AvailableTransferCapability (Non-FirmATC) for anof interfaceis thecapabilityfor non-firmtransmissionreservationsthatNon-Firm ATC remainsafterallowing for existingcommitmentsin theConfirmed
andAcceptedstatus. Mathematically,Non-Firm ATC is calculatedusingtheequation:
Non-FirmATC =
TTC — ExistingFirm & Non-Firm Commitmentsin theConfirmedandAcceptedStatus.
StudyReservations Requestsfor servicethatarein the Study StatusareexcludedfromthecalculationofNon-FirmATC.
Non-Firm TheISO will onoccasionallow Customersto reservehourly non-firmATC = a serviceabovetheTTC for agiven interfacein orderto minimizethenegative degreeofnon-use,aswhenenergyflows arenot scheduledagainstanumber transmissionreservation.In suchcases,theNon-Firm ATC equation
would yield anegativevalueforNon-Firm ATC.
ATC Releasetiming Thevariousclassesof TransmissionServicehavedifferenttimingtables constraintsassociatedwith each.For informationon thewindowof
time openfor requestingeachclassof TransmissionServicepleasereferto TablesTi (Firm Service)andT2 (Non-FirmService)of TheGeneralBusinessPracticesfoundat,http://www.iso-ne.com/transmissionservicesand generationinterconnection/documents/TariffSpecific BusinessPractices/GeneralBusinessPractices/index.html
Additional Release Hourly Non-FirmServiceis releasedpertableT2 of the Generalof Hourly Non-Firm BusinessPractices.Additionally, asofthe noondaily tradingService deadline,calculationof ATC forNon-Firm Hourly Serviceis based
on themaximumavailability of theenergyto bescheduledasopposedto the reservedtransmissionservice. This effectivelyreleasesanyunscheduledtransmissionserviceup to the TTC (nooverbookingis allowed).
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Capacity BenefitMargin (CBM), NotIncludedin NewEngland
ForNEPOOL,‘Existing Firm Commitments’meanstheexistingfirmtransmissionreservations.NEPOOLdoesnot includeaCBMcomponentin anyATC calculations,becausetheCBM is reflectedinthecapacityrequirementsof load-servingentities.
If thecapacityplanningmethodsatNEPOOLchangein thefuture,• the valueoftheCBM componentin theATC calculationswill be re-
evaluated.
ISO/Transmission TheISO calculatesandupdatesFirm andNon-FirmATCsfor serviceProvider with theNEPOOLRTG. ATC for theotherinterfacesis calculatedResponsibility andupdatedby thetransmissionproviderswho postthoseinterfaces.
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NEPOOL Interfaces
Thetenexternalinterfacesfor whichATC valuesarecurrentlypostedon theNEPOOLOASISnodearelistedin thetablebelow. Someoftheseinterfacesconsistofasingletie andothershavemultiple ties.
TheISO determinestheTTC andTRM for eachinterface.TheTransmissionProvidersdeterminethe ATCs basedon existingcommitmentsandpost thevaluesfor TTC andATCs on theirindividualOASIS sites.
Table: NEPOOL Interfaces and TransmissionProviders
Interface TransmissionProviders Comments
NewYork/New England NEPOOLRTG
NYPA/Vermont NEPOOLRTG PostedassubsetofNY-NE
LILCO/Connecticut NEPOOL RTG PostedassubsetofNY-NE
Hydro-Quebec-SandyPond Individual ownersofthehydetie PhaseII, ATC forecastedbyindividual owners
Hydro-Quebec-Comerford Individual ownersof thehydetie PhaseI, ATC forecastedbyindividual owners
NewBrunswick-MEPCO Maine ElectricPowerCompany(MEPCO)
ATC forecastedby MEPCO
NewBrunswick— MPS Maine PublicServiceCompany(MPS)
TTC andATC are forecastedby MPS
Hydro-Quebec-CUin VT CitizensUtilities (CU) HQ Block Load;TTC andATCare forecastedby CU
llydro-Quebec-}lighgate CentralVermont Public ServiceCorporation(CVPS)
MEPCO- New England NEPOOLRTG; MaineElectricPowerCompany(MEPCO)
Separatepostingsby NEPOOLRIG andMEPCO
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Thissectiondescribesconsiderationsusedin determiningTTC andTRM for eachofNEPOOL interfaces.
TheNewYork/New Englandinterfaceconsistsof eight ties:.
1. Plattsburgh-SandBar (PV-20) 115 kV line
2. Whitehall-Blissville(K37) 115 kV line
3. Hoosick-Bennington(K6) 115 kV line
4. Rotterdam-BearSwamp(E205W)230kV line
5. Alps-Berkshire(393)345 kV line6. PleasantValley-LongMountain(398)345 kV line
7. Northport-NorwalkHarbor(1385)138 kV cable
8. Smithfield - Salisbury(690)69 kV line
Basevaluesof theTTC for this interfacearecreatedutilizinghistorical“all lines in” transferlimit data.This datatakesinto accountsuchdiversefactorsasseasonalloaddistributionandfacility ratings,loadlevels,thermalandstability limits, pumpedstorageoperation,andotherfactorsthattypically influenceinterfacetransferlimits.
Historical load data,which is categorizedby day type(weekday,Saturday,andSunday),allowsbasevaluesto bedeterminedfor 24hoursperday for all monthsoftheyear.
TTC & TRM TTC & TRM valuesareshownin thetablebelow.Table: TTC and TRM for New York — NewEngland Interlace
Direction Quantity Value Comments
NY to NE TTC Basedon powerflow studiesorhistoricalvalues
TRM 200MW
NE to NY TTC Basedon powerflow studies
TRM Days I — 12:greaterof 15%or 200MW;
beyond12days: 400 MW
TTC and TRM for NEPOOL Interfaces
New York-New England Interface
Tie Lines
DeterminationofTTC
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NYPA-Vermont Interface
Thevaluesof TTC andTRM forNYPA to Vermontasdeterminedbythe methodsstatedbelowarebasedon thecapabilityof thePV-20line. Theyarethevaluesthat wouldapplyto the interfacetakenonits own. However,valuesof TTC andTRM for NYPA to Vermontarepartof theoverall capabilityof theNew York to New Englandinterfaceandmaybe reducedaccordingly. This is explainedwith anexampleatthe endof thesection.
Table: TTC and TRM for NYPA - Vermont Interface
Direction Quantity Condition Value/Method
NYPA toVT
TIC Summer(5/1-10/31) Up to 140MW
Value is basedon operatingproceduresfor PV-20
Winter (11/1-4/30):Highgateto VT> 200MW
Up to 140 MW
Winter (11/1-4/30):}{ighgate to VT � 200MW
Up to 155 MW
TRM Summer TRM =0
Winter: Highgateto VT>200 MW
TRM = 0
Winter (11/1-4/30):Highgateto VT � 200MW
TRM = 0
VitoNYPA
TIC . TFC=0
Flows in thisdirectionareon anemergencybasisonly
TRIVI TRM = TIC
Examplesof TheATC on theNYPA — Vermontinterfacemaybe limited by theLimitation ATC for theNY to NE interfaceasshownin thefollowing firm ATC
examples.
NYPA/VTATC�NY/NEATC
Suppose:. TTC for NYPA-VT Interface= 140 MW
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• Firm reservationsonNYPA-VT = 100 MW• TRM for NYPA-VT = 0• Firm ATC= TTC- TRM — Firm commitments
If ignoring theNY to NE interfacecapability• FirmATCforNYPAtoVT=(140-O- 100)=4OMW
If Firm ATC forNY to NE Interfaceis greaterthanFirm ATC forNYPA to VT
If FirmATC forNY-NE is 500 MW• FirmATCforNYPAtoVT=(140-0- 100)=4OMW
If FirmATC forNY to NE Interfaceis lessthanFirm ATC forNYPA to VT,
If Firm ATC for NY-NE is 30 MW• Firm ATC for NYPA to Vermont= Firm ATC for NY to NE =
30 MW, since30 MW is lessthanthe40 MW calculatedabovefor NYPA - VT Firm ATC
LILCO-Connecticut Interface
Thevaluesof TTC andTRM for the LILCO — Connecticutinterface
asdeterminedby themethodsstatedbelowarebasedon thecapabilityof the 1385cable. Theyarethevaluesthatwouldapplytothe interfacetakenon its own. However,valuesofTTC/TRM forLILCO — CT arelinked to the overallcapabilityoftheNew York toNewEnglandinterfaceandmaybe reducedaccordingly. Thetreatmentwith respectto theNY - NE interfaceis similar to thatoftheNYPA-VT interface.
LILCO/CTATC�NY/NEATC
TTC andTRIVI valuesfor this interfaceareshownin thetable.
Table: TTC and TRM for LILCO — ConnecticutInterlace
Direction Quantity Value Comments
LILCO toCT
TTC LTC rating ofcable
Thermallimitation for flow onthe 1385 cable.
TRM 0MW
CTtoLILCO:
TIC LIC rating ofcable
ITC is thesamefor bothdirections
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TRM TIC-200
New Brunswick (NB) - MEPCO Interface
Basevaluesof theTTC for this interfacearedeterminedutilizinghistorical“all lines in” transferlimit data.Thisdatatakesinto accountsuchdiversefactorsasseasonalloaddistributionandfacility ratings,loadlevels,thermalandstability limits, andother factorsthattypically influenceinterfacetransferlimits.
TheNew Brunswickto NewEnglandinterfacehasaminimumflowneededto maintainsystemreliability for sourcecontingenciesin theMaritimes.
Notethatthis interfaceis not postedby theNEPOOLRTG; it ispostedby MEPCO.
Table: TTC and TRM for New Brunswick — MEPCO Interlace
Direction Quantity Value Comments
NB to NE: TTC The TTC is basedon the stabilitylimit of 700 MW
TRM As postedby theTransmissionProvider(MEPCO)
NE to NB TT’C: Basedon powerflow studies
Typically zeroor flows requiredfrom NB to NE dueto minimumtieflow reliability requirements
TRM As postedby theTransmissionProvider(MEPCO)
MEPCO-New England InterfaceValuesof TTC for this interfacearebasedon thermallimitationsderivedfrom powerflow analysiswhichreflectsbothsummerandwinter facility ratings.
Valuesareshownin thetablebelow.
Table: TTC and TRM for MEPCO — New England Interlace
Direction Quantity Value Comments
MEPCOtoNE:
TIC Basedonpowerflow studies
Postedby bothNEPOOLRTGandMEPCO.
TRM TRM =ITC-700
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Highgate-Vermont
Table: TTC andTRM for Highgate to Vermont
Direction Quantity Value Comments
HighgatetoVT
TTC 225 MW limit
TRM As postedby theTransmissionProvider(CVPS)
VT toHighgate
TIC TTC= 0 Flowsin this directionareon anemergencybasisonly
TRM As postedby theTransmissionProvider(CVPS)
Hydro-Quebec to SandyPond
This is the interfacefor PhaseII.
Table: TTC and TRM for Hydro-Quebecto Sandy PondInterlace
Direction Quantity Value Comments
HQ to SandyPond
TTC Up to 2000MW
TTC basedon thePhaseII modeofoperation(isolatedor synchronous)andon transferlimitations in NEPOOL,PJM, orNYPP
TRM As postedby the individualTransmissionProvider
SandyPondto HQ
TIC Up to 1200MW
TITCs are basedon theability of theHydro-Quebecsystemto sustainasourcecontingency
TRM As postedby the individualTransmissionProvider
NOTE: PhaseI & II cannotoperatesimultaneously.Normaloperationis overthePhaseII facility..
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Hydro-Quebecto Commerford
This is the interfacefor PhaseI.
Table: TTC and TRM for Hydro-Quebecto Comerlord Interface
Direction Quantity Value Comments
HQ toComerford
TTC Up to 690 MW.
Typically zeroif PhaseII is inservice
Basedon the equipmentratingof 690MW for import toNewEngland
IRM As postedby the individualTransmissionProvider
ComerfordtoHQ
TFC Typically zero For emergencyexportsto HQ
TRM As postedby the individualTransmissionProvider
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Determination and Posting of TTC& ATC
Location ofPostings
TTC andATC valuesfor all NEPOOL PTFinterfacesarepostedontheNEPOOLOASISnode. ThevaluesareaccessedthroughtheOASISsiteoftheTransmissionProviderasidentifiedin thetable,“NEPOOL InterfacesandTransmissionProviders”. Someinterfacesarepostedby morethanoneTransmissionProvider.
Updatesto TTC and ATCTTC andTRM valuesarecalculatedandpostedfor eachofthefollowing time frames:
• Hourly• Daily• Weekly• Monthly• Yearly
BaseTTC valuesforthe longertermpostingsaredeterminedusingan “all lines in” normalsystemconfiguration. Closerto realtime,changesto thenormalconfigurationasaresultofscheduledmaintenanceor unscheduledoutagesareknownandcanresultinmoreor lessrestrictivetransferlimitations.
Shorttermanalysismaybe performedto assesstheeffectsofoutagesandotherchangeson baseTTCs. Adjustmentsto thebaseTTC valuesaremadeto nearertermvaluesasappropriateto reflectthe changesin limitations.
Updatesto TTC The ISO evaluatesall TTC values,with theexceptionof yearlyvalues,for eachinterfaceaminimum of onceperbusinessdayandwheneverchangesin systemconditionswarrant.Forinterfacespostedby providersotherthantheNEPOOLRTG,the ISOprovidestheforecastTTC for interfacesto thetransmissionproviderswithinNewEngland,as indicatedin the tableentitled“NEPOOLInterfacesandTransmissionProviders”onpage5 of this document.
Updatesto ATC TheISO calculatesandupdatesATC for servicewith theNEPOOLRTG severaltimeseachdayfor thenextday andthetime framebeyond,andasneededdue to unforeseenchangesin systemconditions.
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TheISO hasaback-endapplicationthatdynamicallyrecalculatestheATC andupdatesthe OASISpostingaseachtransmissionreservationrequestwith theNEPOOLRTG is confirmed.
ATC for the interfacespostedby othertransmissionprovidersiscalculatedandupdatedby thosetransmissionproviders.
PostedTTC and ATC values
Hourly TTCs & Twenty-four(24)hourly TTC andNon-Firm HourlyATC valuesareATCs: providedfor the currentday,plus thenext11 days,for each
interface.
Adjustmentsmadeto thebaseTTC valuesfor postedinterfacescan
beseenin hour-by-hourdetail.
Daily TTCs & TTC, Firm ATC, andNon-Firm ATC valuesfor thecurrentdayplusATCs: thenext34 daysaresummarizedfor all interfaces
TheTTC valuesfor thefirst 12 daysin this groupareadjustedforhourly maintenanceanddetailscanbeviewedin the HourlyTTCsection. Days 13 through35 usehistoricaldatabaseTTC values.
Weekly TTCs & TTC, FirmATC, andNon-firm ATC valuesareshownfor theATCs: currentweekplus thenext12 weeksfor eachinterface.
A weekalwaysstartsat 0001 onaMondayandendshourending24on the following Sunday.The TTC valueshownis the minimumvaluewithin thedefined7-dayweek.
Notethatthe TTC valuesfor thefirst 5 weeks(madeup of thecurrentweekplusthenext4 weeks)will reflectadjustmentsmadefor knownhourly or daily maintenance.Theremainingweeks(6through13) useTTC valuesfrom thehistoricaldatabaseexceptifmaintenanceis scheduledthatwould effectanyofthoseweeksintheirentirety.
Monthly TTCs & Themonthly TTC andATC valuescoverthecurrentmonthandtheATCs: next12 monthsfor atotal of 13 calendarmonths. Eachinterfacehas
minimumTTC valuespostedwhich arebasedon thehistoricaldatabase.
If maintenanceis scheduledfor anentiremonththeMonthly TTCs
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will reflectit here.
YearlyTTCs & Valuesforthe YearlyTTC reflect2 yearsbeyondthecurrentyear.ATCs: TTC valuesfor eachinterfacearenotpostedon aseasonalbasis,but
ratherindicatetheminimal valuebetweenSummerandWinter
analysis.
Referencedocuments/resources
FurtherinformationaboutTTC/ATC andthe criteriagoverningATC/TTC within NEPOOLis availablefrom the followingdocuments:
• NERC Policy 3, Interchange.SectionE: TransferCapability
• AvailableTransferCapabilityDefinitionsandDetermination.NERC,June,1996
• RevisedNPCCMethodologyandProcedurefor theDeterminationandPostingofAvailableTransferCapability.NPCC,1998
• NEPOOLOpenAccessTransmissionTar~ffAttachmentC.
• NEPOOLOperatingProcedure19 (0P19) TransmissionOperations
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Calculation of Capacity Benefit Margin (CBM) for NEPOOL
It is the current practice of ISO New England Inc. to use 0 MW for CBM whencalculating transfer capabilities on its interconnections with other Control Areas.This practice is based on the capability of generation located within New Englandto reliably meet load and reserve requirements during most hours of the year andon the relatively low usage of NEPOOL ties for supplying loads outside of NewEngland.
Negative Firm Available Transmission Capacity
Why is the firm AvailableTransmissionCapacity(ATC) postedon the OASISa large negative number?
Earlier this yearthe NEPOOLOASISbecamefully subscribedfor Long-TermFirm IN Servicefrom New York. Additional requestsfor Long-TermServiceon thispatharein the studyqueueawaitinga SystemImpact Study. Currently therearefive requestsunderstudy.
OASISreservationsin the accepted,confirmedand studystatusareaccountedfor in thecalculationofATC. TheLong-TermServicerequestsunderstudymakeit appearthat NEPOOLOASIS is oversubscribingfirm andnon-firmservicewell into the future. This is not thecase. No servicewill be grantedtorequestsunder study until ATC is available. ATC availability couldresultfromtransmissionupgradesincreasingtheTotal TransmissionCapacity(TTC) or thereleaseof a confirmedlong-termreservation.
The studyandtransmissionupgradeprocesstakesseveralmonthstocomplete. HoweverISO-NE is requiredto honorthesestudyrequestsin thecalculationof ATC if theapplicantmeetscertaincriteria. The criteriais outlined inSection33 ofthe NEPOOLTariff andincludeschargesto fund the studyandtransmissionupgradework, bothofwhich couldbe substantial. ISO-NE is alsorequiredto honorrenewalrights for existinglong-termserviceagreementsin thecalculationofATC.
Sincetheserequestsare impactingshort-termtransmissionavailability, theTariff, Scheduling& OASIS (TSO)groupat ISO-NE hasdevelopeda methodtomakethis serviceavailableon a near-termbasis. On the first ofeachmonth, theATC calculationlooks for reservationsunderstudythat would be in servicein thenext month. For instance,on December1, any reservationunderstudywith an in-servicetimeframein themonthof Januarywould not be includedin the ATCcalculation. Only onemonthat a time is released.This openstransmissionserviceto Weekly andDaily Firm aswell asall classesof non-firm service. This calculationdoesnot allow availability ofMonthly Firm Servicesincethetimeframefor thistypeservicehasclosedby this time. Cautionmustbe exercisedin releasingthisservicetoo early sinceit is possiblethat a portionof theselong-termrequestscouldbe grantedin a shorterperiodoftime thanis currentlyexpected.
Requestscurrently understudy canbeviewedon OASIS. The effectiveMWamountsthrough the endof theyearare:
November1999 260 MWDecember1999 460 MWJanuary2000 1260 MWFebruary2000 1310 MWMarch — December2000 1410MW