1. SLIDE 1 VICTORIA REGION RESTART July 2013 PRESENTED BY PETER BIDDLE

2. SLIDE 2 AGENDA 1.The System Restart standard 2.What are the proposed changes a)Main assumptions b)Electrical sub-networks c)Quantity of SRAS d)SRAS Definition 3.Restart process a)From NSW b)From SA 4.Questions 5.Summary

3. SLIDE 3 SYSTEM RESTART STANDARD Procure sufficient SRAS to achieve the following targets in each electrical sub-network; o Provide auxiliary supply to sufficient generation within 90 minutes to provide generation & transmission capacity to meet 40% of peak demand within 4 hours For Victoria peak demand = 10,000MW Need to supply 4,000MW capacity within 4 hours The restoration timeframe represents the target timeframe to be used by AEMO in the procurement process. It is not a specification of any operational requirement that should be achieved in the event of a black system condition

4. SLIDE 4 WHAT ARE THE PROPOSED CHANGES Current assumption is that SRAS is procured to manage a NEM wide shutdown o This is an overly conservative assumption o Changing to a Region only shutdown NEM wide shutdown requires each region to be self- supporting for SRAS o Region only shutdown allows use of adjoining regions as a restart supply Currently two electrical sub-networks in Victoria o Region only shutdown provides incentive to consider Victoria as a single electrical sub-network due to connections to other regions

5. SLIDE 5 RECOMMENDED CHANGES (CONT.) Currently four SRAS in Victoria – two in each sub- network o Using supply from NSW & SA plus one SRAS still provides three sources of restart supply o Proposing a minimum of 1 SRAS in each sub-network

6. SLIDE 6 RECOMMENDED CHANGES (CONT.) Current definitions of primary & secondary SRAS has led to a number of perverse outcomes o small gas turbines starting large thermal units at the same power station that do not assist in AEMO meeting the System Restart Standard because:  No output to transmission network for several hours  Do not assist in restarting other generating units o Contracting with diesel units used to restart hydro and gas turbine generating units  Makes testing difficult and inefficient

7. SLIDE 7 RECOMMENDED CHANGES (CONT.) Recommending a single SRAS definition Objective is to ensure contracted services assist AEMO in meeting the System Restart Standard o ≥ 100MW delivered to the local transmission bus within 60 minutes.  Availability/reliability ≥ 90%  Could be delivered by TTHL Hydro Gas Turbines Other o Testing would involve black starting the unit, connecting to the power system and increasing output to contracted output within the contracted timeframe. AEMO is currently consulting with a number of generators to see if changes to this proposal are warranted.

8. SLIDE 8 RESTART PROCESS Under AEMO’s proposal Victoria will have three restart sources o From NSW o From South Australia o SRAS A restart will normally start from all three sources concurrently. o For the purpose of this exercise we will assume SRAS is not available so restart will be managed from connections to NSW & SA only and synchronise at KTS/TTS The aim is to provide auxiliary supply to the majority of power stations within 90 minutes. o If this is done then the time to restore supply capacity is minimised but is then outside AEMO’s control.  Load restoration determined by rate at which power stations can restore capacity

9. SLIDE 9 SOME ASSUMPTIONS No change from current process o All generation & transmission equipment is available for service o Generation capability is in accordance with Local Black System Procedures as provided by Generators o Reasonable time frames allowed for restoration of transmission elements o Load can be restored for voltage control o Major generation Murray Northern Hydros Latrobe Valley – Loy Yang A & B, Hazelwood, Yallourn, Valley Power Gas, Jeeralang A & B Mortlake Laverton North Newport o There are potentially a number of ways to do this

10. SLIDE 10 RESTORATION FROM NSW Energise Murray – auxiliary supply/connection to 1000MW generation made available. Set Murray voltage < 335KV. Energise DDTS 330KV & 220KV bus Energise MBTS – auxiliary supply/connection to 450MW generation at Northern Hydros available When generation on line at MBTS reduce MBTS voltage < 230KV and energise EPS - auxiliary supply/connection to 120MW generation at EPS available Energise SMTS from DDTS– auxiliary supply/connection to 160 MW generation at Somerton made available o load required to be restored at SMTS on energising to manage voltages Energise TTS and complete loop to EPS Restore WOTS – DDTS (completing path back to Tumut) Restore second circuit between DDTS & EPS

11. SLIDE 11 MURRAY TO THOMASTOWN

12. SLIDE 12 RESTORATI0N FROM NSW (CONT.) Restore TTS – ROTS – voltage at TTS < 225KV Restore load ex ROTS sufficient to restart an SVC Restore ROTS – HWPS – auxiliary supply/connection to 1000MW generation at Hazelwood made available. Restore ROTS – YPS – auxiliary supply/connection to 1400MW generation at Yallourn made available. Restore HWPS – JLTS – auxiliary supply/connection to 440MW of generation at Jeeralang made available. Restore HWPS- HWTS – LYPS auxiliary supply/connection to 3000MW of generation at Loy Yang and Valley Power made available. Restore second path between TTS-ROTS-YPS-HWPS- JLTS Synchronise to network restored from SA at KTS/TTS

13. SLIDE 13 THOMASTOWN TO LATROBE VALLEY

14. SLIDE 14 RESTORATION FROM SA Restore S_EAST – HYTS – APD – MOPS 2 line – auxiliary supply/connection made available to 500MW of generation at Mortlake Restore auxiliary loads at APD Restart one unit at Mortlake to assist with voltage control Restore MOPS – MLTS and energise 220KV bus. Restore MLTS – GTS load required at GTS to manage voltage Restore GTS- KTS Restore KTS – ATS – LNGS – auxiliary supply/connection made available to 300MW of generation at Laverton North Restore KTS – ATS – BLTS - KTS loop Restore BLTS – NPS – auxiliary supply/connection made available to 500MW of generation at Newport Synchronise to network restored from NSW at KTS/TTS

15. SLIDE 15 DIAGRAMS

16. SLIDE 16 TIMING ESTIMATES TO MAKE AUXILIARY SUPPLY AVAILABLE Elapsed time = 30 minutes o Murray > 1000MW o Northern Hydros 570MW o Mortlake 500MW Elapsed time = 60 minutes o Somerton 160MW Elapsed time = 90 minutes o Laverton North 300MW o Newport 500MW o Hazelwood 1000MW o Yallourn 1400MW Elapsed time = 120 minutes o Jeeralang 440MW o Loy Yang & Valley Power 3000MW

17. SLIDE 17 AFTER 4 HOURS – LIKELY SUPPLY CAPACITY NSW/Murray 1000 MW Northern Hydros 500 MW Somerton 160 MW Mortlake 500 MW SA connection 400 MW Newport 500 MW Laverton North 300 MW Jeeralang 400 MW Yallourn 300 MW Hazelwood 400 MW Loy Yang 1000 MW Valley Power 300 MW Basslink 300 MW (cannot be used in initial restart process) Total = 6060MW (require 4000 MW to meet the SRS)

18. SLIDE 18 QUESTIONS

19. SLIDE 19 SUMMARY Region only shutdown Move to a single electrical sub-network One SRAS to be procured Revised SRAS definition Still three sources of restart supply Expect to be able to provide auxiliary supply/connection to the majority of power stations within 90 minutes even without an SRAS Rate of load restoration will depend on rate of generation restoration and is outside AEMO’s control.