Rooftop solar delivers 62% of total generation, drives demand to record low in WA

Rooftop solar reached a peak of 62 per cent of total generation in Western Australia’s main grid over the weekend, creating a new record low of “operational demand” and underlining the rapid change in the shape of the grid.

The new benchmark was noted by the Australian Energy Market Operator, which is responsible for running the South West Interconnected System, and is keeping a sharp eye on the growing share of rooftop solar and the declining share of the assets over which it has control.

AEMO says that the weekend sunny skies allowed rooftop solar to generate around 62% of total demand at 12:30-1pm local on Sunday.

That share wasn’t a record in itself – rooftop solar reached a 65.2 per cent share in March this year – but it did lead to a new minimum operational demand record of 866MW, which AEMO noted was nearly a 10% drop since the previous record of 952MW less than six months ago on March 14 this year.

ln fact, just a year ago, a new record low for minimum demand was set at 1059MW last September, when rooftop solar provided 40 per cent of total generation. And that was below the previous record of 1135MW set in January, 2020. Which means it has fallen nearly 300MW in  20 months.

AEMO has set 700MW as the minimum grid demand level that can be accommodated without serious impacts on grid stability, but even at that level it would suggest heavy curtailment of non-synchronous generation (wind and solar).

It and the government have been leading the push for higher inverter standards and the “solar shedding” protocols which has been tested in South Australia, along with other initiatives to increase load at times of high solar output.