© Commonwealth of Australia.

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Spot prices were aligned across the mainland for 95 per cent of the time, averaging between $21/MWh in Queensland and $27/MWh in South Australia. The average weekly price in Tasmania was $32/MWh. Turnover in the energy market was $82 million. The total cost of ancillary services for the week, including Tasmania, was around $480 000, or approximately 0.6 per cent of energy market turnover. Significant variations between actual prices and those forecast 4 and 12 hours ahead occurred in 29, or around 9 per cent of all trading intervals. Demand forecasts produced 4 and 12 hours ahead varied from actual by more than 5 per cent in around a quarter of all trading intervals across the market. These variations were most frequent in South Australia occurring in two thirds of all trading intervals. Energy prices Figure 1 sets out national demand and spot prices in each region for each trading interval. Figure 2 compares the volume weighted average price with the averages for the previous week, the same quarter last year and for the financial year to date. Figure 3 compares the weekly price volatility index with the averages for the previous week and the same quarter last year. Figure 1: national demand and spot prices

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© Commonwealth of Australia.

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Figure 2: volume weighted average spot price for energy market ($/MWh)

QLD NSW VIC SA TAS Last week 21 22 22 27 32 Previous week 17 20 26 31 45 Same quarter last year 23 28 27 36 - Financial year to date 33 46 37 45 65 % change from previous week* ▲24% ▲8% ▼16% ▼15% ▼27% % change from same quarter last year** ▼9% ▼23% ▼18% ▼25% - % change from year to date*** ▲1% ▼7% ▲26% ▲12% -

*The percentage change between last week’s average spot price and the average price for the previous week. **The percentage change between last week’s average spot price and the average price for the same quarter last year. ***The percentage change between the average spot price for the current financial year to date and the average spot price over the similar period for the previous financial year.

Figure 3: volatility index during peak periods

QLD NSW VIC SA TAS Last week 0.55 0.46 0.50 0.37 0.12 Previous week 0.39 0.41 0.41 0.31 0.22 Same quarter last year 0.73 0.74 0.78 0.70 -

Figures 4 to 8 show the weekly correlation between spot price and demand.

Figure 4: Queensland Figure 5: New South Wales

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© Commonwealth of Australia.

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Figure 8: Tasmania

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Maximum spot prices across the mainland ranged from $87/MWh in New South Wales to $98/MWh in South Australia, these all occurred at 6.30pm on Thursday. In Tasmania, the maximum spot price reached $75/MWh on Wednesday afternoon. Figure 9 sets out the d-cyphaTrade wholesale electricity price index (WEPI) for each region throughout the week excluding Tasmania. Figure 10 sets out the WEPI since 1 January 2004. Figure 9: d-cyphaTrade WEPI for the week

Monday Tuesday Wednesday Thursday Friday Queensland N/A 38.63 39.23 38.83 39.06 New South Wales N/A 42.88 43.58 43.45 42.95 Victoria N/A 35.07 35.35 35.71 35.69 South Australia N/A 39.83 40.74 40.81 41.44 Figure 10: d-cyphaTrade WEPI

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© Commonwealth of Australia.

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Figures 11 to 15: spot price, net import and limit at time of weekly maximum demand

Figure 11: Queensland Figure 12: New South Wales

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© Commonwealth of Australia.

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Price variations

There were 29 trading intervals where actual prices significantly varied from forecasts made 4 and 12 hours ahead of dispatch. Figures 16 to 20 show the difference in actual and forecast price versus the difference in actual and forecast demand. The figures highlight the relationship between price variation and demand forecast error. The information is presented in terms of the percentage difference from actual. Price differences beyond 100 per cent have been capped.

Figure 16: Queensland Figure 17: New South Wales

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© Commonwealth of Australia.

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Figure 21 summarises the number and most probable reason for variations between forecast and actual prices. Figure 21: reasons for variations between forecast and actual prices

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Price and demand Figures 22 - 51 set out details of spot prices and demand on a regional basis. They include the actual spot price, actual demand outcomes and variation from forecasts made 4 and 12 hours ahead of dispatch on a daily basis. The differences between the maximum temperature and the temperature forecast at around 6.00 pm the day before are also included. Figures 52 - 56 set out for each region the extent of capacity offered into the market within a series of price thresholds. Actual price and generation dispatched in a region are overlaid.

© Commonwealth of Australia.

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Figures 22-27: Queensland actual spot price, demand and forecast differences

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© Commonwealth of Australia.

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There were four occasions in Queensland where the spot price was greater than three times the weekly average price of $21/MWh. Thursday, 20 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 88.80 96.44 24.54 Demand (MW) 7032 6897 6903 Available capacity (MW) 8331 8231 8774

Conditions at the time saw demand and availability close to forecast. Price was close to forecast four hours ahead, and aligned across the mainland. At around 11 pm the previous evening, Tarong Energy’s Tarong North tripped from 440 MW. At around 2 pm a delay in the return of the unit saw 440 MW of capacity removed for the 6.30pm trading interval. All of this capacity was priced at less than $11/MWh. The rebid reason given was “RTS Delayed::Adjust Profile”. As much as 225 MW of capacity at Wivenhoe was shifted from prices above $9000/MWh to below $100/MWh by Tarong Energy over the course of the day. The rebid reasons given were “F Change in PD::Extend W2 run” and “F Change in PDS”. There was no other significant rebidding. Friday, 21 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 62.61 40.97 23.04 Demand (MW) 6473 7149 6773 Available capacity (MW) 7976 8361 8774

Conditions at the time saw demand around 700 MW lower than forecast 4 hours ahead. Available capacity was 400 MW lower than forecast 4 hours ahead and 800 MW lower than 12 hours ahead. Price was aligned across the mainland. At around 5.30 pm, Enertrade’s Gladstone unit 3 tripped from 245 MW. Most of this capacity was priced below $30/MWh. The unit returned to service at around 9.30 pm. Further delays in the return of Tarong Energy’s Tarong North, following its trip on Wednesday, saw 440 MW of capacity removed from the 6.30pm trading interval through a rebid at around midday. All of this capacity was priced at less than $15/MWh. The rebid reason given was “RTS Delayed::Adjust Profile”. There was no other significant rebidding.

© Commonwealth of Australia.

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Saturday, 22 April 9:30 am Actual 4 hr forecast 12 hr forecast Price ($/MWh) 64.72 25.61 25.88 Demand (MW) 5829 5999 5999 Available capacity (MW) 8128 8282 8282

Conditions at the time saw demand and available capacity close to forecast, with prices aligned across the mainland. At 9 am, CS Energy reduced the availability of Callide B2 by around half or 185 MW. Most of this capacity was priced at less than $15/MWh. The rebid reason given was “CB2 ash plant problems”. There was no other significant rebidding. Saturday, 22 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 83.38 85.69 28.95 Demand (MW) 6204 6271 6175 Available capacity (MW) 8129 8097 8725

Conditions at the time saw demand, available capacity and price close to forecast 4 hours ahead, with prices aligned across the mainland. There was around 600 MW of low priced capacity removed from the market, compared to that forecast 12 hours earlier, following further delays in the return of Tarong Energy’s Tarong North, and the reduction of CS Energy’s Callide B 2 earlier in the day. There was no other significant rebidding.

© Commonwealth of Australia.

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Figures 28-33 New South Wales actual spot price, demand and forecast differences

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© Commonwealth of Australia.

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There were three occasions in New South Wales where the spot price was greater than three times the weekly average price of $22/MWh. Thursday, 20 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 87.04 92.19 25.01 Demand (MW) 9936 10 002 9953 Available capacity (MW) 10 367 10 505 10 505

Conditions at the time saw demand and available capacity close to forecast four hours ahead, with prices were aligned across the mainland. There was no significant rebidding. Saturday, 22 April 9:30 am Actual 4 hr forecast 12 hr forecast Price ($/MWh) 71.55 27.46 27.77 Demand (MW) 8744 8697 8811 Available capacity (MW) 8659 8895 8895

Conditions at the time saw demand close to forecast with availability around 250 MW lower than forecast four hours ahead. Prices were aligned across the mainland. Rebids made close to dispatch saw reductions in availability totaling around 250 MW, across the Macquarie Generation and Eraring portfolios and at Redbank. Most of this capacity was priced at less than $30/MWh. There was no other significant rebidding. Saturday, 22 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 86.79 88.60 32.99 Demand (MW) 9259 9359 9301 Available capacity (MW) 9235 9235 9280

Conditions at the time saw demand, available capacity and price close to forecast four and 12 hours ahead, with prices aligned across the mainland. There was no significant rebidding.

© Commonwealth of Australia.

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Figures 34-39: Victoria actual spot price, demand and forecast differences

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© Commonwealth of Australia.

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There were three occasions in Victoria where the spot price was greater than three times the weekly average price of $22/MWh. Thursday, 20 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 90.27 93.42 26.34 Demand (MW) 6977 6639 6503 Available capacity (MW) 7255 7246 7408

Conditions at the time saw demand 350 MW higher than forecast four hours ahead with available capacity and price close to forecast. Prices were aligned across the mainland. There was no significant rebidding. Saturday, 22 April 9:30 am Actual 4 hr forecast 12 hr forecast Price ($/MWh) 72.88 28.15 27.87 Demand (MW) 5763 5785 5781 Available capacity (MW) 6927 7109 7223

Conditions at the time saw demand and available capacity close to that forecast four hours ahead. Prices were aligned across the mainland. Available capacity was 300 MW lower than forecast 12 hours ahead. From midnight, International Power reduced the available capacity at Hazelwood by around 490 MW. The rebid reasons given were “Coal Supply Problem”, Fuel limitation” and “Draft Plant Limit”. As a result of the coal supply problems, unit one at Hazelwood was shutdown at around 8am. The unit finally returned to service around midnight. There was no other significant rebidding. Saturday, 22 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 89.73 92.90 34.77 Demand (MW) 6353 6252 6245 Available capacity (MW) 7011 7149 7242

Conditions at the time saw demand and available capacity close to forecast four hours ahead. Prices were aligned across the mainland. Available capacity was 250 MW lower than forecast 12 hours ahead. . There was around 180 MW of low priced capacity removed from the market following delays in the return of International Power’s Hazelwood unit 1 from an outage earlier in the day. There was no other significant rebidding.

© Commonwealth of Australia.

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Figures 40-45: South Australia actual spot price, demand and forecast differences

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© Commonwealth of Australia.

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There were two occasions in South Australia where the spot price was greater than three times the weekly average price of $27/MWh. Thursday, 20 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 96.70 98.95 30.03 Demand (MW) 1563 1554 1527 Available capacity (MW) 2088 2091 2091

Conditions at the time saw demand and available capacity close to that forecast 4 hours earlier. Prices were aligned across the mainland. There was no significant rebidding. Saturday, 22 April 6:30 pm Actual 4 hr forecast 12 hr forecast Price ($/MWh) 98.05 99.41 38.00 Demand (MW) 1483 1463 1454 Available capacity (MW) 1944 1944 1944 Conditions at the time saw demand and available capacity close to forecasts, with prices aligned across the mainland. There was no significant rebidding

© Commonwealth of Australia.

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Figures 46-51: Tasmania actual spot price, demand and forecast differences

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There was no occasion where the spot price in Tasmania was greater than three times the weekly average price of $32/MWh.

© Commonwealth of Australia.

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Figure 52: Queensland closing bid prices, dispatched generation and spot price

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Figure 53: New South Wales closing bid prices, dispatched generation and spot price

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© Commonwealth of Australia.

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Figure 54: Victoria closing bid prices, dispatched generation and spot price

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Figure 55: South Australia closing bid prices, dispatched generation and spot price

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© Commonwealth of Australia.

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Figure 56: Tasmania closing bid prices, dispatched generation and spot price

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Ancillary service market The total cost of ancillary services on the mainland for the week was around $445 000 or 0.7 per cent of the total turnover in the energy market on the mainland. Figure 57 summarises the volume weighted average prices and costs for the eight frequency control ancillary services across the interconnected regions.

Figure 57: frequency control ancillary service prices and costs

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Last week 2.78 1.00 1.95 1.28 0.29 0.32 1.54 1.89

Previous week 2.78 0.91 1.46 1.16 0.31 0.31 1.08 1.84

Last quarter 1.76 0.73 1.15 1.54 0.39 2.28 5.00 1.93

Market Cost ($1000s) 147 53 131 28 3 3 38 41

% of energy market 0.24% 0.09% 0.21% 0.05% 0.00% 0.01% 0.06% 0.07%

The total cost of ancillary services in Tasmania for the week was $35 000 or 0.2 per cent of the total turnover in the energy market in Tasmania. Figure 58 summarises for Tasmania the prices and costs for the eight frequency control ancillary services.

© Commonwealth of Australia.

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Figure 58: frequency control ancillary service prices and costs for Tasmania

Raise 6 sec

Raise 60 sec

Raise 5 min

Raise reg

Lower 6 sec

Lower 60 sec

Lower 5 min

Lower reg

Last week 0.15 0.10 0.10 0.12 1.69 0.11 0.10 0.11

Previous week 0.15 0.10 0.10 4.93 0.44 0.10 0.10 0.10

Last quarter 7.89 1.05 1.05 1.58 4.43 1.06 1.06 1.97

Market Cost ($1000s) 1 1 1 1 25 3 3 1

% of energy market 0.01% 0.00% 0.00% 0.00% 0.12% 0.02% 0.01% 0.00% Figure 59 shows the daily breakdown of cost for each frequency control ancillary service. Figure 59: daily frequency control ancillary service costs

020,000

40,00060,00080,000

100,000120,000

16/4/06 17/4/06 18/4/06 19/4/06 20/4/06 21/4/06 22/4/06

$

Raise 6sec Raise 60sec Raise 5min Raise Reg. Lower 6sec Lower 60sec Lower 5min Lower Reg

Figure 60 shows the contribution, on a percentage basis, that frequency control ancillary service providers are utilised (in each mainland region) to satisfy the total requirement for each service.

Figure 60: regional participation in ancillary services on the mainland

0%20%40%60%80%

100%

Raise 6second

Raise 60second

Raise 5minute

Raiseregulating

Lower 6second

Lower 60second

Lower 5minute

Lowerregulating

Queensland New South Wales Snowy Victoria South Australia

Figures 61 and 62 show 30-minute prices for each frequency control ancillary service throughout the week.

© Commonwealth of Australia.

21

Figure 61: prices for raise services

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3

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9

12

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

$/M

W

Raise Reg Raise 5min Raise 60sec Raise 6sec

Figure 61A: prices for raise services - Tasmania

0

1

2

3

4

5

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

$/M

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Raise Reg Raise 5min Raise 60sec Raise 6sec

Figure 62: prices for lower services

0

2

4

6

8

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

$/M

W

Lower Reg Lower 5min Lower 60sec Lower 6sec

Figure 62A: prices for lower services - Tasmania

0

2

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8

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

$/M

W

Lower Reg Lower 5min Lower 60sec Lower 6sec

Figures 63 and 64 present for both raise and lower frequency control services the requirement, established by NEMMCO, for each service to satisfy the frequency standard.

© Commonwealth of Australia.

22

Figure 63: raise requirements

0

125

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375

500

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

MW

Raise Reg Raise 5min Raise 60sec Raise 6sec

Figure 63A: raise requirements - Tasmania

0

25

50

75

100

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

MW

Raise Reg Raise 5min Raise 60sec Raise 6sec

Figure 64: lower requirements

0

50

100

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200

16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

MW

Lower Reg Lower 5min Lower 60sec Lower 6sec

Figure 64A: lower requirements - Tasmania

0

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16/04/06 17/04/06 18/04/06 19/04/06 20/04/06 21/04/06 22/04/06

MW

Lower Reg Lower 5min Lower 60sec Lower 6sec

Australian Energy Regulator May 2006