Rooftop PV propels renewables to 75 pct share for first time, sends coal and grid demand to record lows

A surge in rooftop solar output has propelled the share of renewables output on Australia’s main grid to a record high of 75.2 per cent, and sent the share of coal and operating demand levels down to record lows.

The new milestone was reached on Sunday at 11.15 (AEST) when the share of renewables past 75 per cent for the first time in a five minute trading period, beating the previous peak of 74.4 per cent set just 14 days earlier. On Monday, the record was broken again when renewables hit a new instantaneous peak of 75.3 per cent.

The biggest contributor on Sunday was the output of the more than 21 gigawatts (GW) of solar panels mounted on rooftops across the main grid, with rooftop PV also setting a new record share of 52 per cent, up from 50.4 per cent that it set a week earlier.

Of course, when there are winners there are also losers, and the nation’s slowly dwindling fleet of ageing coal fired generators posted a new record low share of 24.1 per cent at 11.05 AEST, and a record low output of 6,042 MW at 11.50 AEST, much below the previous low of 6,380 MW.

Operational demand on the main grid also fell to a new low of 10,489 MW at midday AEST on Sunday. Another demand measure – “market demand” – dropped below 10,000 MW for the first time ever, according to another data source at Watt Clarity.

Coal fired generators are being forced to dance around the surging output of rooftop solar, particularly in spring time when mild temperatures mean that demand is not high.

Many units are forced to ramp down and up rapidly, some are even being switched off and then back on in the same shift, and those that cannot manage that bid the wholesale price into negative territory to ensure they are dispatched.

“As coal continues to decline, and renewable energy reaches new milestones, the focus on energy storage and grid management becomes even more critical to maintaining stability and supporting Australia’s clean energy future,” Geoff Eldridge, an energy analyst with GPE NEMLog, wrote on LinkedIn.

State-based records also fell. As we reported on Saturday, the share of rooftop PV hit a stunning new record of 112.9 per cent of state demand in South Australia, while on Sunday rooftop PV hit a new peak of 55.2 per cent in NSW, the country’s biggest grid and with the biggest coal fleet.

Queensland, normally Australia’s most dependent coal state in terms of generation share, posted a new record instantaneous renewable share of 77 per cent on Sunday afternoon.