Rooftop solar pushes WA grid demand to 8-year low

Rooftop solar has helped push grid demand in Western Australia to its lowest levels in more than eight years, in yet another example of how the technology is hollowing out demand during the middle of the day.

It used by the night time that represented minimum demand in most Australian states, but the arrival of rooftop solar and the creation of the so-called “duck-curve” of demand means that the middle of the day is now setting new lows.

After South Australia set new record lows on several occasions in the past few weeks, W.A. recorded on Sunday its lowest level of demand since November 1, 2009.

It reached a low of 1265MW in the 12pm to 1230pm trading interval on Sunday, when there was around 420MW of output from rooftop solar PV.

This won’t be the end of the story. The local grid operator expects that over the next decade, the level of rooftop solar – possibly on 90 per cent of businesses and two thirds of homes – will actually push minimum grid demand down to zero on some occasions.

Already, this year, installations are racing 49 per cent ahead of the record levels of 2016, and total installations in the main WA grid now total 785MW. By 2027, AEMO expects this to jump to around 1,800MW, significantly more than the minimum demand now. But in a high installation scenario, it says it could be 2,200MW by 2027.

That is going to increase the need for storage, and for more flexible generation to respond to the growing penetration of large scale wind and solar, and the rapidly increasing uptake of rooftop solar.

W.A. has shown the sharpest percentage increase in rooftop solar over the last 12 months,