While the Australian Energy Market Operator is not expecting any loss of power, it has forecast a lack of back-up power reserves of around 200 megawatts on Thursday. Despite AEMO cancelling a potential shortage of reserves on Wednesday, the breakdowns were still forecast to drive up wholesale power prices on the day to more than $14,000 a megawatt hour in NSW and Victoria from midday until 7pm, as well as briefly spiking up to $14,000 in South Australia towards the end of the day. AEMO is forecasting price spikes in NSW, Victoria and South Australia on Wednesday. Credit:AEMO While electricity demand is expected to reach a peak of about 13,456 megawatts on Wednesday and just under 14,000 on Thursday, those totals are still well below the NSW all-time high of 14,764, reached in the summer of 2010/11. Rooftop solar, though, will act to keep customers from tapping the grid for power, masking the full electricity demand, Dylan McConnell, from Melbourne University's Climate & Energy College, said.

The two generator breakdowns come as NSW faced temperatures of more than 41 degrees in the state's west on Wednesday and similar or warmer conditions are tipped on Thursday. Loading On Wednesday, the strain on the electricity market may come less from the spike to extreme heat in state capitals than the wide area that will see warm temperatures. From Adelaide to Melbourne, temperatures are expected to climb into the mid to high 30s, with Brisbane and Sydney both forecast to top 30 degrees. Inland suburbs of both cities, though, will be a lot hotter - reaching the mid-30s in Sydney's west - ahead of even hotter conditions on Thursday.