Solar eclipses coal as primary fuel source in Australian grid

Two of the past three days have included periods when solar energy eclipsed coal as the lead source of power across the National Electricity Market (NEM) as Australia’s switch from fossil fuels to a renewables-dominated future continues.

The emergence of solar as the lead source of power in August was first noted on Friday, when it beat out coal for 35 minutes as the primary fuel source in the NEM, which includes all states and territories except Western Australia and the Northern Territory. That effort was eclipsed on Sunday when solar shone brightest for three hours and 20 minutes.

At noon on Sunday, the solar market share in the NEM reached 45.9%, with rooftop PV and utility scale solar producing  a combined 11,213 MW of power while the combined supply of black and brown coal was 39.9% (9,752 MW). Rooftop solar accounted for most of the solar market share, delivering 30.7% while large-scale assets provided 15.2%. In total, renewables provided 58.6% of the market’s power.

Solar also dominated in Western Australia’s main grid on Sunday, responsible for 65.2% of midday generation requirements while coal’s market share dropped to 14% in the Southwest Interconnected System (SWIS). Rooftop solar dominated the solar market share, delivering a staggering 61% of energy in the market. Renewables, including wind, hydro and storage totalled 66.4% generation.

While it is not the first time solar has dominated the market, Joshua Stabler, managing director of Brisbane-based energy consulting firm Energy Edge, said it is the first time it has happened under relatively normal conditions, noting it was not caused by a shortage of coal-fired power, and it happened outside of summer.

“This is the first time in business-as-usual that we’ve ever seen coal be dethroned as [the] number-one fuel source in the market,” he told the ABC. “Coal has been at times up to 80 or 90% of the amount of energy coming into the market. Which means that this is a big event.”

Stabler said he expects solar to play an increasingly prominent role in electricity production in the coming months.

“This is just the first of many events like this,” he said. “Each sort of spring-ish period, what we have is a lot of sun in the sky and not a lot of demand.

“What we will see is more and more events where solar becomes the number-one generator in the market. The coming Sundays over August and September will be testing the 50% market share boundary where demand remains subdued but solar capacity grows.

“While peak solar dispatch will still occur during summer, the hotter weather will bring higher demand so this is the optimal period in terms of maximum market share for solar.”