Victoria and South Australia have just finished a week which put the highest stress on the electricity grid since a similar heatwave occurred on 28th-30th January 2009. Despite the population of Victoria and South Australia increasing at least 7%2 since then, the electricity demand supplied by the grid during the heat wave was just lower than the peak usage reached on the 29th of Jan 2009.
Electricity demand from the grid in the recent heatwave peaked on Wednesday. There were initially warnings of potential load shedding1 from the grid operator after the usually baseload Loy Yang A3 brown coal unit and one of the Torrens Island gas units tripped offline on Tuesday. However, demand came in slightly lower than forecast and apart from some minor local transmission outages, demand was fully supplied.
Speculation has already started on the effect of solar on electricity demand during the heat wave, with the Electricity Supply Association (ESAA)3 and the Australian Solar Council4 each producing different estimates of the amount solar contributed to reducing demand. Peak demand is an important driver of the cost of electricity as both the network and the generation fleet is sized to meet the largest credible demand forecast.