NECA has published the report of our investigation into the events of Monday 27 November. Prices in South Australia reached $2,305/MWh for the trading interval ending at 5pm on that day, with a maximum price of $4,390/MWh in three despatch intervals. The average price for the day was $165/MWh. The maximum temperature that day was 39C and demand of 2,616 MW was only 30MW less than the highest ever. Energy consumption was one-and-a-half times the average for the quarter. Low reserve conditions in South Australia were forecast from as early as the previous Tuesday.
Available generation capacity and gas supplies were anyway inevitably stretched under those demand conditions. At around 2pm, however, a breakdown of equipment on the Moomba to Adelaide gas pipeline affected gas supplies to Torrens Island and Pelican Point power stations. Pelican Point reduced its capacity by 160MW from around 3.30pm and Torrens Island by some 80MW between 4.30pm and 6pm. There were some 740 effective rebids for the period 3pm and 6pm, of which over 300 were submitted within two hours of despatch.
The main conclusions of our report are that the majority of those rebids, by Torrens Island TXU SA and National Power SA, were related to their management of the gas supply situation and commitment of replacement plant. Overall they represented a rational and prudent, but at the same time commercial, response to circumstances that arose at short notice. There is scope, however, to improve the coordinated scheduling arrangements for gas supplies to Torrens Island, Osborne, Pelican Point, Dry Creek and Mintaro power stations. The Electricity Supply Industry Planning Council of South Australia should undertake a review of those arrangements.
The rebidding by NRG Flinders, however, was not directly related to the gas supply problem. The reason given by NRG Flinders for its rebids was financial optimisation. Moreover, it appears that NRG Flinders committed its Playford station without prior notification to the market and without giving NEMMCO advance notice. We are continuing to investigate this apparent failure to provide the required information.
