The autumnal heatwave in New South Wales has produced a new record for electricity demand in March, with residents making the biggest demand on the grid in more than three years.
NSW residents required 13,136 megawatts as Sydney recorded its hottest day in more than two years and the third highest on record for March.
The low-intensity heatwave is expected to continue for Sydney, the Illawarra and Hunter regions until a cool change arrives on Wednesday afternoon.
Jonathon Geddes from the Australian Energy Market Operator (Aemo) said high temperature drove a peak demand at around 6pm Monday.
High temps in Sydney yesterday set a new NSW electricity demand record for March (13,136 MW), ~1,000 MW higher than the previous record (12,173 MW on 9 March 2016). Gen mix at the time: black coal (52.7%), hydro (16.2%), gas (9.4%), wind (6.1%) & grid-scale solar (5.8%). pic.twitter.com/z1auN7r9UU
— AEMO (@AEMO_Energy) March 7, 2023
The evening peak was the likely result of the sun going down and rooftop solar coming off the grid at the same time as people came home and wanted to use electricity for cooling and cooking purposes, according to Geddes.
“It’s the highest demand we’ve seen in New South Wales since February 2020,” he said. “We have been in La Niña weather pattern for several years.”
The national electricity market “held up well”, Geddes said, with enough generation to meet supply and no disruption to energy consumers related to the high demand.
The total generation capacity in NSW stood at about 20,000MW, and 60,000MW in the national electricity markets, he said. The all-time record for electricity demand in NSW was 14,744MW in February 2011.
Geddes said peak demand was typically in summer during heatwave periods, as cooling required more energy than heating, resulting in more minimum-demand days in winter, spring and autumn.
Jonathan How, a senior forecaster at the Bureau of Meteorology, said because a heatwave was a combination of high daytime temperatures staying warm overnight, the body was not able to recover properly and that could pose a health risk.
The conditions were often especially difficult for elderly Australians and those with medical conditions, How said.
On Tuesday, temperatures reached 34C in the Sydney CBD and 36C at the airport at 2.30pm, with temperatures still rising.
How said the hottest place in NSW on Tuesday was Williamtown in Newcastle, which reached 37.7C.
More than 30 fires were burning in the state on Tuesday, 10 of which were yet to be brought under control.
It’s going to be a HOT week 🔥 Our @HeatHealth_USYD researchers are pioneering work on evidence-based ways that people can keep cool & stay safe. Their recommendations in @TheLancet below ⬇️ pic.twitter.com/XAi1Z7dsKw
— Sydney Health (@syd_health) March 6, 2023
Prof Ollie Jay, director of the heat and health incubator at the University of Sydney, said exposure to extreme heat events that lasted for several days could cause heat-related illnesses, from heat exhaustion to heatstroke.
People with heart disease were also susceptible, Jay said, because one of the first ways the human body responded to heat was to redistribute blood towards the skin. This meant the heart had to beat more often to stop blood pressure from dropping.
People with kidney problems could also be more vulnerable during heat events due to dehydration caused by sweating, he said.
Jay said most Australians coped with the heat by using air-conditioning.
Older Australians were vulnerable as they might not have air-conditioning or use it due to a spike in electricity costs, he said.
