Analysis Table 1 shows actual and forecast spot price, demand and availability for each high price trading interval. For most of the high-priced periods, half hour demand and availability was close to that forecast four hours ahead. The exception was the 8 pm trading interval, during which demand was around 250 MW higher than forecast. Table 1 also shows that high prices were forecast four hours ahead only for the 5 pm and 5.30 pm trading intervals. The following analysis (sections 3.1 and 3.2) shows that rebidding by participants created supply conditions, such that small variations in demand had the potential to lead to large variations in price. Table : Actual and forecast demand, spot price and available capacity Time Price ($/MWh) Demand (MW) Availability (MW) Actual 4 hr 12 hr Actual 4 hr 12 hr Actual 4 hr 12 hr forecast forecast forecast forecast forecast forecast 2 pm 6737 37 39 8011 7974 7932 9991 10 053 10 099 2.30 pm 8980 64 37 8117 8109 8049 9979 10 083 10 099 3.30 pm 10 060 41 39 8317 8337 8233 10 080 10 089 10 134 4 pm 8993 2158 43 8385 8440 8329 10 101 10 085 10 134 4.30 pm 13 499 2158 45 8422 8506 8400 10 046 10 142 10 134 5 pm 13 499 13 499 45 8445 8563 8412 10 052 10 105 10 114 5.30 pm 8989 13 499 39 8395 8360 8225 9810 9844 9864 6 pm 4527 96 35 8252 8155 8037 9773 9828 9864 8 pm 2299 301 31 8153 7906 7863 9853 9887 9890 Rebidding All significant rebids that contributed to the high prices are contained in Appendix A. Figure 2 graphically summarises significant rebids made within 12 hours of dispatch and which were effective during the high price periods. Coloured areas above the horizontal axis represent capacity rebid from low prices to high prices for each trading interval, by participant. Coloured areas below the horizontal axis represent (generally low-price) capacity withdrawn for each trading interval.
Analysis Table 1 shows actual and forecast spot price, demand and availability for each high price trading interval. For most of the high-priced periods, half hour demand and availability was close to that forecast four hours ahead. The exception was the 8 pm trading interval, during which demand was around 250 MW higher than forecast. Table 1 also shows that high prices were forecast four hours ahead only for the 5 pm and 5.30 pm trading intervals. The following analysis (sections 3.1 and 3.2) shows that rebidding by participants created supply conditions, such that small variations in demand had the potential to lead to large variations in price. Table : Actual and forecast demand, spot price and available capacity Time Price ($/MWh) Demand (MW) Availability (MW) Actual 4 hr forecast 12 hr forecast Actual 4 hr forecast 12 hr forecast Actual 4 hr forecast 12 hr forecast 2 pm 6737 37 39 8011 7974 7932 9991 10 053 10 099 2.30 pm 8980 64 37 8117 8109 8049 9979 10 083 10 099 3.30 pm 10 060 41 39 8317 8337 8233 10 080 10 089 10 134 4 pm 8993 2158 43 8385 8440 8329 10 101 10 085 10 134 4.30 pm 13 499 2158 45 8422 8506 8400 10 046 10 142 10 134 5 pm 13 499 13 499 45 8445 8563 8412 10 052 10 105 10 114 5.30 pm 8989 13 499 39 8395 8360 8225 9810 9844 9864 6 pm 4527 96 35 8252 8155 8037 9773 9828 9864 8 pm 2299 301 31 8153 7906 7863 9853 9887 9890 Rebidding All significant rebids that contributed to the high prices are contained in Appendix A. Figure 2 graphically summarises significant rebids made within 12 hours of dispatch and which were effective during the high price periods. Coloured areas above the horizontal axis represent capacity rebid from low prices to high prices for each trading interval, by participant. Coloured areas below the horizontal axis represent (generally low-price) capacity withdrawn for each trading interval.