SLIDE 1 SRAS REVIEW QUEENSLAND REGION July 2013 PRESENTED BY PETER BIDDLE

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)North b)South 4.Questions 5.Summary

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 QLD South peak demand = 5100MW o Need to supply 2040MW capacity within 4 hours For QLD North peak demand = 3400 o Need to supply 1360 MW 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

SLIDE 4 RECOMMENDED CHANGES Current assumption is that SRAS is procured to manage a NEM wide shutdown 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 three electrical sub-networks in Queensland o QLD North, QLD Central & QLD South

SLIDE 5 RECOMMENDED CHANGES (CONT.) Recommending a combination of the central & north sub- networks  Connections between these areas recently strengthened Now 3 275KV lines from Nebo to Ross + 132KV connections Now 4 275KV lines between Nebo and Broadsound/Bouldercomb + 132KV connections 3 275KV lines between Calvale & Stanwell + 132KV connections and 2 additional 275KV lines in Nov 2013 Currently 6 SRAS in Queensland – 2 x south, 3 x central & 1 x north o Proposing a minimum of 1 SRAS in each sub-network

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

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.

SLIDE 8 RESTART PROCESS Under AEMO’s proposal Queensland will have a minimum of three restart sources o From NSW o At least 1 SRAS in south o At least 1 SRAS in north A restart will normally start from all three sources concurrently. o For the purpose of this exercise we will assume a restart from NSW is not available so restart will be managed from the SRAS only. 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

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 may be restored for voltage control o Major generation  North – Callide, Stanwell, Gladstone, Townsville GTs  South – Tarong, Kogan, Millmerran, Wivenhoe, Swanbank, Braemar, Darling Downs, Oakey. o There are potentially a number of ways to do this

SLIDE 10 RESTORATION - NORTH Assume SRAS is Stanwell – TTHL service Energise Stanwell to Calvale and restore 132Kv bus o Restore load at Biloela and/or Moura and auxiliary supply to Callide power stations Energise Stanwell to Bouldercombe then Callipoe River and restore 132KV bus o Restore load at Gladstone North and auxiliary supply to Gladstone o Restore auxiliary supply to Boyne Island (Sensitive load) Energise Bouldercombe to Nebo and start SVC. o Restore load at Mackay and start GT Energise Nebo to Strathmore and start SVC Energise Strathmore to Ross and start SVC and energise 132KV bus Energise 132Kv line to Townsville South and to Mount Stuart o Start GTs at Mount Stuart.

SLIDE 11 STANWELL TO CALVALE & CALLIOPE RIVER

SLIDE 12 BOULDERCOMBE TO STRATHMORE

SLIDE 13 STRATHMORE TO ROSS TO CHALUMBIN

SLIDE 14 TIMING ESTIMATES TO MAKE AUXILIARY SUPPLY AVAILABLE Elapsed time = 30 minutes o Stanwell 1400MW o Callide 1500MW Elapsed time = 60 minutes o Gladstone 1600MW Elapsed time = 90 minutes o Mackay 30 MW o Mt Stuart 400MW Elapsed time = 120 minutes o Townsville 245MW o Kareeya 80MW

SLIDE 15 AFTER 4 HOURS – LIKELY SUPPLY CAPACITY Stanwell 700 MW Callide B 700 MW Callide C 800 MW Gladstone 560 MW Mackay 30 MW Mt Stuart 400 MW Townsville 285 MW Kareeya 80 MW Barron Gorge 60 MW Total = 3615MW (1360MW required to meet SRS)

SLIDE 16 RESTORATION - SOUTH Assume SRAS is Wivenhoe Energise Tarong and restore 66KV bus o Energise 132KV system to Chinchilla & Columbula o Restore load at Tarong plus Tarong auxiliary supply o Restore load at Chinchilla o Auxiliary supply to Roma and Condamine Energise Mt England to Blackwall and start SVC Energise Blackwall to Greenbank and start SVC Energise Greenbank to Swanbank E Energise Greenbank to Belmont and restore load Energise Tarong to Braemar and start SVC o Supply restored to Braemar & Darling Downs power stations

SLIDE 17 RESTORATION - SOUTH Start second Wivenhoe unit Energise Tarong to Blackwall Energise Tarong to Middle Ridge and through to Oakey GTs o Auxiliary supply to Oakey GTs Energise Braemar to Western Downs Energise Kogan o Auxiliary supply to Kogan Energise Braemar to Bulli Creek and Millmerran o Auxiliary supply to Millmerran

SLIDE 18 WIVENHOE TO TARONG & BRAEMAR

SLIDE 19 TARONG TO MIDDLE RIDGE

SLIDE 20 BRAEMAR TO WESTERN DOWNS & BULLI CREEK

SLIDE 21 TIMING ESTIMATES TO MAKE AUXILIARY SUPPLY AVAILABLE Elapsed time = 30 minutes o Wivenhoe 500 MW o Tarong 1800MW o Roma 80 MW o Condamine 140 MW Elapsed time = 60 minutes o Swanbank E 400 MW o Braemar & Darling Downs 1500MW Elapsed time = 90 minutes o Kogan 740 MW o Milmerran 880 MW o Oakey 340 MW

SLIDE 22 AFTER 4 HOURS – LIKELY SUPPLY CAPACITY Tarong 0 MW Tarong North 0 MW Swanbank E 400 MW Roma & Condamine 220 MW Wivenhoe 500 MW Braemar 1000 MW Darling Downs 500 MW Kogan 740 MW Milmerran 0 MW Oakey 340 MW Total = 3700MW (2040MW required to meet SRS)

SLIDE 23 QUESTIONS

SLIDE 24 SUMMARY Region only shutdown Move to two electrical sub-networks Minimum of one SRAS to be procured per sub-network Still three sources of restart supply Expect to be able to provide auxiliary supply/connection to all major generation within 90 minutes. Rate of load restoration will depend on rate of generation restoration and is outside AEMO’s control.