Rooftop solar pushes South Australia grid demand to new record low

Rooftop solar has helped push operational grid demand in the renewable state of South Australia down to a new record low of 475MW, according to a new update from the Australian Energy Market Operator.

The new low in operational demand (the red dotted line in graph above) occurred on Sunday at 1230pm (grid time, which is AEST), just over a week after rooftop solar and large scale solar combined to deliver 80 per cent of the state’s total demand, on Saturday, October 12, and a week after the state had apparently set a previous record low.

“This is the second week in a row that a new record for South Australia’s minimum operational demand has been set, and a strong sign of just how quickly Australia’s energy industry is transforming,” AEMO says in a blog post on its Energy Live website.

AEMO defines operational demand as the amount of power consumers require from Australia’s wholesale energy markets. This does not include power generated by behind-the-meter resources, like rooftop PV, which AEMO noted has already proven itself as a key driver behind these new records, along with energy efficiency.

“At the time of the new record, rooftop solar was generating approximately 821 megawatts of power, which equalled 64% of the total demand required in South Australia. If you add in power generated by utility solar and wind generation, approximately 90% of the state’s native demand was met by renewable sources,” said AEMO’s Chief Operations Officer, Damien Sanford.

Sanford noted that rooftop solar usually has its maximum output during the middle of the day, when most people are not at home, and minimum demand levels are often set in spring, when mild weather combines with clear and sunny conditions that are ideal for rooftop solar.

AEMO said, however, that the growing share of rooftop solar created challenges for managing key system requirements such as frequency and voltage.

AEMO has been working with network and consumer groups to find a way to make rooftop solar and other distributed resources, such as battery storage and electric vehicles, more “visible” so it can be better managed.

This is likely to require things like new inverter standards, and technologies such as virtual power plants. Reviews are ongoing in both the country’s main grid, and in Western Australia, which also has a high penetration of rooftop solar.

AEMO has previously forecast that operational demand in states like South Australia and W.A. could reach zero in coming years, hence the focus on new technologies and storage to manage the phenomenon.

The Liberal government in South Australia has a target of reaching “net 100 per cent” renewables, most likely by 2030, but probably well before that. It wants to be a renewable energy powerhouse and deliver cheap wind and solar to other states, and to export markets.