Electricity Week - Daily frequency control ancillary service cost 27 December 2009 - 2 January 2010

First 5 of 5 paragraphs shown The total cost of frequency control ancillary services (FCAS) on the mainland for the week was $138 000 or less than one per cent of energy turnover on the mainland. The total cost of FCAS in Tasmania for the week was $883 000 or about 20 per cent of energy turnover in Tasmania.
-Prices: On 31 December prices for raise 6 second FCAS reached $10 000/MWh from the 7.40 pm to 8.40 pm dispatch intervals (inclusive), dropping to around $4000/MWh from 8.45 pm to 9 pm and then returned to $10 000/MWh from the 9.05 pm to 9.10 pm dispatch intervals (inclusive).
- Data:The table summarises (as a percentage) the number of times when the actual price differs significantly from the forecast price four or 12 hours ahead and the major reason for that variation. The reasons are classified as availability (which means that there is a change in the total quantity or price offered for generation), demand forecast inaccuracy, changes to network capability or as a combination of factors (when there is not one dominant reason). An instance where both four and 12 hour ahead forecasts differ significantly from the actual price will be counted as two variations. 7 A peak period is defined as between 7 am and 10 pm on weekdays, which aligns with the SFE contract definition.
- What Happened: As a result of lightning storms in Tasmania in the evening of 31 December, AEMO declared the trip of several transmission lines as credible contingency events from 7.30 pm to 9.40 pm. At 8.22 pm AEMO issued a direction to a generator to supply raise 6 second FCAS. AEMO issued market notices declaring an intervention price dispatch period from the 8.35 pm dispatch interval to 9.15pm and a further market notice announcing that due to over-constrained dispatch the dispatch intervals from 7.40 pm to 9.10 pm would be reviewed. As required under 3.13.7 of the Electricity Rules, the AER will be issuing a report into the reasons why the FCAS prices exceeded $5000/MWh. Figure 12 shows the daily breakdown of cost for each FCAS for the NEM.
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