Spot prices for the week averaged $24/MWh in Queensland, $27/MWh in New South Wales, $26/MWh in Victoria and $28/MWh in South Australia. These prices were consistent with the previous week.
In Tasmania average spot prices decreased by a third to $66/MWh. A reduction in demand and an increase in the availability of ancillary services contributed. The five-minute price on Friday reached $10 000/MWh, when lightning affected network capability and reduced the availability of low priced generation. On Saturday, lightning led to the loss of three transmission lines in Tasmania’s north. Around 100 MW of load was disconnected as a result.
Turnover in the energy market for the mainland was $105 million, with a total cost of ancillary services for the week of around $376 000 or 0.4 per cent of turnover. Turnover in Tasmania was $13 million, with ancillary services totaling $366 000 or three per cent of turnover.
Demand forecasts produced four and 12 hours ahead varied from actual by more than five per cent in a quarter of all trading intervals across the market. In South Australia and Tasmania demand errors occurred in around half and a third of all trading intervals respectively, on the same basis. Significant variations between forecast and actual prices occurred in 23 or seven per cent of all trading intervals.
The AER would welcome comments on the information contained in, or the layout of, the report. Comments should be sent to Peter Adams or Mark Wilson, AER, 14th floor, 13 Grenfell Street, Adelaide SA 5001 (email peter.adams@aer.gov.au; mark.wilson@aer.gov.au; fax (08) 8213 3414).
Figure 1 sets out national demand and spot prices in each region for each trading interval. Figure 2 compares the volume weighted average price with the averages for the previous week and the same quarter last year. Figure 3 compares the weekly price volatility index on the same basis.
Figure 1 National demand and spot price all regions
Figure 2 Volume weighted average spot price for energy market ($/MWh)
The maximum spot prices for the week across the mainland ranged from $117/MWh in New South Wales to $93/MWh in Victoria. These prices occurred on Sunday and Monday respectively. In Tasmania, the spot price reached $3373/MWh at midday on Friday.
There were no low reserve conditions forecast throughout the week.
The total cost of ancillary services on the mainland for the week was $376 000 or 0.4 per cent of the total turnover in the energy market. A short notice outage in Victoria on Monday led to an increased requirement for lower services.
Figure 4 Volume weighted average frequency control ancillary service prices (excluding Tasmania)
Raise
Lower
6 sec
60 sec
5 min
Reg
6 sec
60 sec
5 min
Reg
Last week($/MW)
1.97
1.47
1.13
1.42
0.21
0.29
1.36
1.47
Previous week ($/MW)
1.45
0.93
0.95
0.99
0.2
0.23
1.31
1.59
Last quarter ($/MW)
1.43
0.69
0.98
1.36
0.16
0.12
1.16
1.58
Market cost($1000s)
111
83
81
31
2
3
34
32
% of energy market
0.12%
0.09%
0.09%
0.03%
0%
0%
0.04%
0.03%
In Tasmania, ancillary services totaled $366 000 or three per cent of turnover. The price for raise six second reached $10 000/MW at 11.40am and 11.45am on Friday when the requirement was not met. Constraints invoked to manage the loss of both Farrell to Sheffield lines to lightning increased the requirement for raise 6 second by around 70 MW and removed around 70 MW, or half of the total availability of raise six second in the region.
On Wednesday, despatch for raise and lower regulation was zero as a result of a failure of the SCADA system. The price for these services reached $10 000/MWh at the time. This had no impact on the cost of these services for the week.
Figure 5 Tasmanian volume weighted average frequency control ancillary service prices
Raise
Lower
6 sec
60 sec
5 min
Reg
6 sec
60 sec
5 min
Reg
Last week($/MW)
13.36
1.05
1.06
1.06
13.39
1.07
1.06
1.11
Previous week ($/MW)
54.01
1.05
1.05
4.98
13.61
1.06
1.06
1.25
Tasmania Market cost($1000s)
100
8
9
9
173
32
26
9
% Tasmania of energy market
0.78%
0.06%
0.07%
0.07%
1.34%
0.25%
0.2%
0.07%
Figure 6 shows the daily breakdown of price for each frequency control ancillary service. It also includes the cost of services sourced locally and in Tasmania.
Figure 6 Daily frequency control ancillary service prices
Figure 7 shows the weekly participation in each of the ancillary service markets on a regional basis.
Figure 7 Regional participation in ancillary services
Figures 8 and 9 show 30-minute prices for each of the ancillary services.
Figure 8 Prices for raise services
Figure 9 Prices for lower services
Figures 10 and 11 show the 30-minute Tasmanian price for each or the ancillary services.
Figure 10 Tasmanian prices for raise services
Figure 11 Tasmanian prices for lower services
Figures 12 and 13 present both the raise and lower requirements for each service over the week.
Figure 12 Raise requirements
Figure 13 Lower requirements
Figures 14 and 15 present both the raise and lower Tasmanian requirements for each service over the week.
