New analysis from the Australia Institute’s Climate & Energy program shows that rooftop solar delayed and reduced peak demand in the National Electricity Market (NEM) this summer. This improved the reliability of the grid, covering for coal-fired power plants during breakdowns.

When demand was highest this summer rooftop solar reduced peak demand by over 2000 MW, the equivalent of a large coal power plant.

Household solar also stepped into the breach, more than compensating for the large breakdown at Loy Yang B power Station, which occurred during another period of high demand.

 “Hot days are the greatest challenge for our electricity system and especially for gas and coal-fired generators. Our system now struggles to meet peak demand without rooftop solar and other renewables,” says Ben Oquist, Executive Director of The Australia Institute.  

“The great thing about solar is that it reliably produces power on hot, sunny days, just when we need it.

“We often hear that solar doesn’t work when the sun doesn’t shine. Fortunately, the sun does shine, a lot, exactly when we need solar most.”

“The sun shining is the cause of our electricity system’s demand peaks. It is the cause of many breakdowns in our gas and coal-fired generators,” says Mark Ogge, researcher at The Australia Institute and author of the report.

“We saw this when Loy Yang B broke down on January 18th, and solar stepped into the breach.

The analysis shows that rooftop solar delayed peak grid demand many hours on hot days.  In South Australia, the peak was delayed by eight hours on one hot day, and over six hours in Queensland.

“Solar delays peak grid demand by several hours on hot days and reduces its size by thousands of megawatts.

“As more households install batteries, this effect will last further into the evening.

“If governments are serious about energy security, providing incentives for solar panels and batteries should be a key priority, rather than building more unreliable coal and gas plants.”