Experts reveal solar panels lost nearly 20 per cent of their efficiency in NSW heatwaves

While the heat is difficult to deal with, surely the summer scorcher have had at least one positive spin-off — record solar power generation. Not so. Experts estimate many solar panels lose their efficiency in NSW’s heatwave.

Across the state the sun blazed away in cloudless skies, but surely the summer scorcher must have had at least one positive spin-off — record solar power generation.

Not so. Experts estimate many solar panels lost nearly 20 per cent of their efficiency in NSW’s heatwave as they struggled to cope with blistering temperatures.

Separate figures compiled by the Australian PV Institute estimated that photovoltaic output from the state’s solar power systems was as low as 55 per cent of capacity around midday on Thursday when the mercury was topping 40C across NSW.

Leading academics researching the effect of heat on solar panels said older models lost 0.5 per cent of their efficiency for every degree their temperature went over 25C.

Solar panels are losing efficiency during heatwaves. Picture: iStock

University of New South Wales solar energy professor Martin Green said newer models with better technology suffered a 0.4 efficiency drop per degree in severe heat.

“On a normal day they will still operate at 20C above the ambient temperature so in relative terms on days like yesterday they are running at 4 per cent less efficient to normal,” he said.

“On a hot day like today it is beneficial or the old electricity grid would be drained with everyone running their airconditioners.”

Green Energy Markets director Tristan Edis said that while there was “bucketloads” of solar radiation around in ­heatwaves, solar panels lost energy through the panels and converters.

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“Even though it is hot and there is a lot of sun they don’t generate as well in the heat,” he said.

“The ideal days are in November when it is 26-28C. Forty degrees and no clouds is not as good.”

Carbon Friendly Enterprises certified solar installer Jemal Solo said ventilation around the panels was important in keeping the temperatures down.

“There are a lot of variables around that affect the efficiency regarding (the loss of efficiency) from heat,” he said.

“These are the type of panel, manufacturer’s standards, if they have been installed properly, if there is adequate airflow around the panels, and dust. “It is also the tilt angle of the roof and their orientation to the sun.”

Green Energy Markets director Tristan Edis said solar panels don’t generate as well in the heat.

At UNSW Professor Green said he was working on new solar cells with increased efficiency on hot days. The designs incorporate natural cooling and can also operate at lower temperatures.

Australian PV Institute chair Renate Egan said solar was still better than coal-fired power stations on a hot day.

“Coal-fired power plants are known to shut down completely on hot days,” she said.

The solar figures come as the heatwave caused a 50 per cent spike in electricity demand across NSW yesterday.

The Australian Energy Market Operator said that ­demand had reached 13,147MW — compared to the 9600MW average.

Originally published as Experts reveal solar panels lost nearly 20 per cent of their efficiency in NSW heatwaves