This weekend, Sydney recorded its hottest 48 hours in November in recorded history. Here's what it means for our electricity supplies.

Temperatures in Sydney reached 42 degrees this weekend, with a low of 25.3 degrees on Saturday night providing the only relief. According to the Bureau of Meteorology, heatwaves at this time of the year aren't unusual, but "the temperatures and duration of what we're going to see is exceptional”. As heatwaves become more frequent, power experts have concerns we don’t have electricity systems that can handle the amount of power we need to get through them.

Heatwaves impact the electricity system more than any other single event - air conditioners, which can make up half of all power demand during a heatwave, put a massive strain on the system. Over the weekend, the Australian Energy Market Operator (AEMO) said there might not be enough reserve capacity (Lack of Reserve Level 1) in New South Wales on Sunday afternoon between 3.30pm and 5.30pm. It raises some serious questions about how equipped we are to deal with heatwaves.

Electricity companies typically monitor weather forecasts to look for the type of heatwave that came over the weekend to get ready for the spike in demand. To do this, they activate the back-up energy supplies in anticipation for huge requirement of the system. In places like Adelaide, that have a strong renewable power supply grid, authorities work out how much non-renewable power they will need to supplement the existing supply.