1. Public 1 Ontario Transmission System Presentation to F&ASC April 16, 2003

2. Public 2 Ontario Transmission System - Highlights Nine major internal interfaces Ten transmission zones Eight interconnection points with Manitoba, Minnesota, Quebec, Michigan & New York Generally, several transmission networks at 500 kV, 230 kV and 115 kV voltage levels

3. Public 3 Map of Ontario

4. Public 4 NWNE Essa TorontoSWEast Niagara West Bruce NY Niagara Michigan NY St. Lawrence Quebec future HVDC FABC EWTW / EWTE CLAN / CLAS FN / FS BLIP / NBLIP FETT QFW Minnesota Manitoba Ontario Transmission System Ottawa Quebec FIO Lake Erie future HVDC

5. Public 5 Definition of Interface/Interconnection Interface and Interconnection definitions are formed by grouping one or more circuits (lines) for the purpose of measuring their combined flow at specific points and enforcing a power flow limit in MW.

6. Public 6 Major Interfaces East-West (EW) - EW Transfer East(EWTE) & EW Transfer West (EWTW) Flow North (FN)/Flow South (FS) Claireville North (CLAN)/Claireville South (CLAS) Flow Away from Bruce Complex (FABC) Buchanan Longwood Input (BLIP)/Negative BLIP (NBLIP) Queenston Flow West (QFW) Flow East Towards Toronto (FETT) Transfer East from Cherrywood (TEC) Flow Into Ottawa (FIO)

7. Public 7 Interface Limit Characteristics ‘Base’ limit All transmission facilities are in-service Directional Certain outages result in a penalty in MW Respect thermal limitations Preserve system and/or plant stability and maintain acceptable post-contingency voltage Some limits simple constants; others more complex

8. Public 8 Interface Base Limits

9. Public 9 EWTE/EWTW Interface Boundary between the NW and NE zones Power flows related to power flows with Manitoba & Minnesota EWTE limit - 325 MW - preserve system stability EWTW limit - 350 MW - preserve system stability & maintain acceptable pre-contingency voltages Power flows from NW to NE

10. Public 10 FN/FS Interface Boundary between the NE and Essa zones FN limit - 1,900 MW - maintain acceptable post- contingency voltages FS limit - 1,400 MW - preserve plant stability

11. Public 11 CLAN/CLAS Interface Boundary between the Essa and Toronto zones CLAN limit - 2,000 MW CLAS limit - 1,000 MW Limits define boundary conditions for other system limits

12. Public 12 FABC Interface Boundary between the Bruce zone and the West and Southwest zones Flows are out FABC limit - 4,050-4,450 MW 4 units; 4,440-4,950 MW 5 units; 4,500-5,300 MW 6 units Preserve system and/or plant stability & maintain acceptable post-contingency voltages Limit improvement with generation rejection

13. Public 13 BLIP/NBLIP Interface Boundary between the West zone and the Bruce and Southwest zones BLIP limit - 3,500 MW - preserve system and/or plant stability & maintain acceptable pre-contingency and post-contingency voltages NBLIP limit - 1,500 MW - maintain acceptable post- contingency voltages NBLIP limit dependent on Bruce, Lambton & Nanticoke and reactor switching availability

14. Public 14 QFW Interface Boundary between the Niagara and SW zones QFW limit - 1,750 MW Summer; 1,950 MW Winter - respect thermal limitations Real-time, limit determined by ambient weather conditions No limit for flows opposite to QFW direction

15. Public 15 FETT Interface Boundary between the SW zone and the Essa and Toronto zones FETT Limit - 5,700 MW - preserve system and/or plant stability & maintain acceptable voltages Limit dependent on Nanticoke, Lakeview, Darlington, Pickering & Lennox plus FS flow Summer limit dependent on Ontario Demand No limit for flows opposite to FETT direction

16. Public 16 TEC Interface Boundary between the Toronto and East zones No pre-defined limit

17. Public 17 FIO Interface Boundary between the East and Ottawa transmission zones FIO Limit - 1,900 MW - maintain acceptable post- contingency voltages Real-time limit improvement with load rejection No limit for flows opposite to FIO direction Quebec High Voltage Direct Current (HVDC) interconnection project - limit increase to 3,000 MW

18. Public 18 NWNE Essa TorontoSWEast Niagara West Bruce NY Niagara Michigan NY St. Lawrence Quebec future HVDC 3120 MW 240 MW 650 MW 615 MW 215 MW 2925 MW 1010 MW Minnesota Manitoba Snapshot Flows Jan. 23, 2003 @ approx. 18:00 hrs Ottawa Quebec 1470 MW Lake Erie future HVDC 325 MW

19. Public 19 NWNE Essa TorontoSWEast Niagara West Bruce NY Niagara Michigan NY St. Lawrence Quebec future HVDC 3115 MW 50 MW 1910 MW 935 MW 255 MW 3165 MW 315 MW Minnesota Manitoba Snapshot Flows Jan. 23, 2003 @ approx. 3:30 hrs Ottawa Quebec 1245 MW Lake Erie future HVDC 1775 MW

20. Public 20 NWNE Essa TorontoSWEast Niagara West Bruce NY Niagara Michigan NY St. Lawrence Quebec future HVDC FABC EWTW / EWTE CLAN / CLAS FN / FS BLIP / NBLIP FETT QFW Minnesota Manitoba Ontario Transmission System Ottawa Quebec FIO Lake Erie future HVDC

21. Public 21 Interconnections Ontario-Manitoba - Ontario-Manitoba Transfer East (OMTE) & Ontario-Manitoba Transfer West (OMTW) Ontario-Minnesota - Minnesota Power Flow North (MPFN) & Minnesota Power Flow South (MPFS) Ontario-Michigan

22. Public 22 Interconnections (Continued) Ontario-New York Niagara & Ontario-New York St Lawrence Ontario-Quebec North & Ontario-Quebec South Quebec & Lake Erie HVDCs (future installations) Most of Ontario’s non-radial interconnections are under phase angle regulator (PAR) control, except for New York Niagara and part of Michigan (today)

23. Public 23 Interconnection Limit Characteristics ‘Base’ limit All transmission facilities are in-service Directional Certain outages result in a penalty in MW Manitoba & Minnesota - PAR deadband margins recognized in limits Quebec - summer and winter limits

24. Public 24 Interconnection Limit Characteristics (Continued) Michigan & New York - range of summer and winter flow limits Respect thermal and/or stability limitations Real-time, thermal limitations determined by ambient weather conditions Ontario coincident import/export capability - many factors

25. Public 25 Interconnection Base Limits

26. Public 26 Ontario-Manitoba & Ontario-Minnesota Interconnections PAR controlled Imports & exports constrained by stability and thermal limitations OMTW limit - 275 MW; OMTE limit - 275 MW; SK1 115kV limit - 49MW MPFN limit - 90 MW; MPFS limit - 140 MW

27. Public 27 Ontario-Quebec North Interconnection Radial connection Imports & exports are constrained thermal limitations Summer limits - imports 65 MW; exports 95 MW Winter limits - imports 84 MW; exports 110 MW

28. Public 28 Ontario-Quebec South Interconnection Radial connection Imports are constrained by stability limitations and available Quebec generation Exports are constrained by stability and thermal limitations Summer limits - imports 1,385 MW; exports 740 MW Winter limits - imports 1,385 MW; exports 760 MW

29. Public 29 Ontario-New York St. Lawrence Interconnection PAR controlled Imports & exports are constrained by thermal limitations Limit - imports 400 MW; exports 400 MW

30. Public 30 Ontario-New York Niagara Interconnection Free flowing Imports & exports are comprised of scheduled flows plus unscheduled parallel path flows A range of flow limits for different weather and generation dispatch conditions Lower flow limit - unfavourable operating conditions; constrained by thermal limitations

31. Public 31 Ontario-New York Niagara Interconnection (Continued) Higher flow limit - favourable operating conditions; constrained by thermal limitations Generally, import capability never fully utilized Summer limits - imports 1,000-1,300 MW; exports 700- 1,800 MW Winter limits - imports 1,200-1,500 MW; exports 1,000- 2,000 MW

32. Public 32 Ontario-Michigan Interconnection Partial PAR control & free flowing (today) Imports & exports are comprised of scheduled flows plus unscheduled parallel path flows Full PAR control (Summer 2003) Imports & exports are expected to more closely match scheduled flows Partial vs. full PAR control does not materially change the flow limits

33. Public 33 Ontario-Michigan Interconnection (Continued) A range of flow limits for different operating conditions Exports - lower flow limit - no generation rejection is armed at Lambton Imports - higher flow limit - low generation levels at Lambton and TransAlta - Sarnia Summer limits - imports 700-1,700 MW; exports 1,700- 2,100 MW Winter limits - imports 1,200-1,700 MW; exports 1,800- 2,200 MW

34. Public 34 Unscheduled Power Flow - Michigan-Ontario-New York Lake Erie Circulation (LEC) is an unscheduled parallel path flow involving Michigan, Ontario & New York Occurs naturally Circulates through Ontario in a clockwise or counterclockwise direction Aggravates the BLIP and QFW interfaces Utilization of full PAR control at Michigan will control LEC in either direction to levels less than 600 MW

35. Public 35 Scheduled Power Flow - Michigan-Ontario-New York With partial PAR control at Michigan (MI), scheduled power flows across the MI and New York (NY) Niagara interconnections depend on system conditions When full PAR at MI is utilized, scheduled power flows with MI are more likely to be regulated across the MI interconnection This will alleviate unscheduled flows on the NY Niagara interconnection and in turn, allow scheduled flows with New York to be maintained

36. Public 36 NY - Michigan Scheduled import example with partial PAR control Beck Generation = 1800 Niagara load = 800 QFW pre-load = 1000 QFW limit = 1750 permissible inflow on NY interface = 750 Michigan Import Limit = 1700 Michigan Import Schedule = 1700 Michigan flow into Ontario = 1190+129 = 1319 Michigan contribution on NY = 510 NY max additional import flow = 750 - 510 = 240 NY max schedule = 240 / 0.65 = 369 NY contribution on Michigan = 129 NY flow = 750 Import from NY & Michigan = 1700 + 369 = 2069 Michigan flow = 0.7 Michigan schedule + 0.35 NY schedule NY flow = 0.3 Michigan schedule + 0.65 NY schedule

37. Public 37 Ontario Coincident Import/Export Capability With partial PAR control at MI, the coincident import/export capability is unlikely to equal the arithmetic sum of the individual flow limits When full PAR control is utilized, the coincident import/export capability could equal the arithmetic sum of the individual flow limits

38. Public 38 Ontario Coincident Import/Export Capability - Range

39. Public 39 2,964 MW=324(MB)+90(MN)+400(NY St. Lawrence) +65(QC North)+1,385(QC South)+700(min. MI only) 3,964 MW=324+90+400+65+1,385+700(min. MI) +1,000 (min. NY Niagara) 5,264 MW=324+90+400+65+1,385+1,700(max. MI) +1,300 (max. NY Niagara) Ontario Coincident Import/Export Capability - Example

40. Public 40 Ontario Coincident Import Capability Higher value in ranges achieved with low generation dispatch levels Generation levels rarely, if ever, materialize Expected Ontario coincident import capability is approximately 4,000 MW

41. Public 41 IMO Reports on Transmission Capacity Interface and interconnections limitations are identified in the IMO Security Status Report (SSR), Security and Adequacy Assessment Report (SAA) and 18-Month Outlook Different time periods covered Limitations identified as a penalty in MW Penalty is applied against the ‘base’ limit

42. Public 42 Example - SSR Report for April 11, 2003 FETT Base limit=5,700MW; Limit=5,700-150-350=5,200MW

43. Public 43 End