Transpower says high demand during the summer period could leave lakes depleted by the middle of next year. Photo: 123RF
Energy researchers fear the country will face an electricity shortage next winter if demand does not ease.
Transpower says high demand during the summer period could leave lakes depleted by the middle of next year, when demand increases further as temperatures drop.
Dr Kimberley O'Sullivan, an energy hardship expert at the University of Otago's Department of Public Health, said a survey of 219 people during the summer of 2021 to 2022 showed air conditioning was a key driver of increased demand during summer.
Summer electricity demand up, Transpower concerned about next winter
"Of the 65 percent that had a heat pump at home, 75 percent of them were already using this for cooling," she told Nine to Noon. "I was really surprised to find we've already had this transition from passive cooling, opening doors and windows, to relying more on heat pumps and fans."
As temperatures steadily increased throughout New Zealand, she said people were looking for ways to cool down.
"Almost everybody was doing something to cool their house during summer - 97 percent of people are trying something sometimes to keep cooler.
"Forty-five percent had an electric fan, and just under 30 percent were only ever using passive cooling."
Mark Todoroff, an energy demand forecaster at TESLA Forecasting, said the gap in demand between summer and winter was narrowing.
"Winter, the peak hits around just over 7 gigawatts and in summer it's around 5.5 gigawatts," he explained. "But we are noticing that the demand in the summer is much more weather sensitive than it's been historically, and a lot of that is from the heat pumps."
He said that was changing how forecasters modelled the demand.
"Historically we would have trained our model on tens of years of data with very little sensitivity to those higher temperatures, but that's all changing so we need to allow the models to adapt.
"We're noticing the seasons to be a lot wider than they used to be. When I first started forecasting demand it was really June to August that we were concerned about high demand... but now we're actually seeing quite a bit of colder weather randomly and at the end of March, April and October."
O'Sullivan said New Zealand's energy system needed to evolve.
"We've definitely got people using more electricity than they would have previously in the summer. This is part of the reason why I really think we need to start thinking about solar, because [in] summer the sun's shining, we're at home and wanting to use air conditioning."