Friday, December 4, 2020
Renewable Energy News

Electricity provider authorised to switch off rooftop solar in SA in emergencies – ABC News

By Staff , in Solar Power , at August 27, 2020

Authorities in South Australia will have the power to deliberately “trip” existing rooftop solar panels in rare circumstances to prevent another statewide blackout, with similar emergency powers being sought for use in Victoria and Queensland.

The Australian Energy Market Operator (AEMO) is urging the change as it grapples with technical challenges posed by rapid growth of solar power.

Australia’s rapid uptake of panels has moved periods of so-called “minimum demand” in most states from the middle of the night to the middle of the day.

In states like South Australia and Victoria, the uptake of solar has been so successful that minimum demand on mild days in spring is now edging closer to zero.

AEMO’s Electricity Statement of Opportunities, published today, states that South Australia is on track to record low minimum demand of just 250 to 350 megawatts by spring.

The report states that in some scenarios, SA could reach zero minimum demand as soon as 2023.

A graph with several lines trending mostly downwards.
South Australia’s minimum electricity demand could hit zero by 2023.(Supplied: AEMO)

Low demand poses a major problem for operating the grid securely, particularly when South Australia’s ability to export electricity to the eastern states is hampered.

The state was separated from the rest of the national grid for 18 days last summer, after transmission towers in Victoria were severely damaged by wild weather.

SA the ‘canary in the coal mine’

The state’s electricity distributor, SA Power Networks, had already been given the power to switch off all new solar installations from next month.

But AEMO said that alone was not enough, revealing it was in negotiation with SA Power Networks to potentially power down existing panels.

“It is anticipated that PV shedding would only be enabled under rare circumstances, as a last resort to maintain system security under abnormal condition,” the report states.

Solar panels on a roof overlooking Adelaide.
Many South Australian homes are heavily reliant on solar panels.(ABC News: Dean Faulkner)

SA Power Networks spokesman Paul Roberts said in practice, solar households would be forced to draw their power from the grid rather than their panels, temporarily boosting demand.

“What we’re talking about here is actually lifting voltage levels in some areas to trip off inverters so people’s solar stops generating to the network for a while,” Mr Roberts told ABC Radio Adelaide.

“That means the electricity that they need to keep their house going will actually come from the grid.

While the changes in South Australia will take effect immediately, AEMO suggests similar action is “required urgently in Victoria, and promptly in Queensland”.

“South Australia will be the canary in the coal mine on this, because AEMO [has] already said that Victoria within a couple of years could be in the same position because of the same problem,” the Grattan Institute’s energy program director Tony Wood said.

The report states that while New South Wales and Tasmania present lower risks, the new mitigation mechanism could be rolled out across the entire National Electricity Market.

In the longer term, AEMO has flagged other solutions to the challenges posed by minimum electricity demand.

It suggests more widespread use of storage, coordinated charging of electric vehicles and so-called “demand response”, where homes and businesses could be incentivised to shift more energy use to the middle of the day.