18th June, 2020
Matt Smith, Political Editor, The Advertiser
Household solar panel systems could be turned on and off under State Government instructions in a bid to avert statewide blackouts predicted as early as this spring, a new report shows.
The unprecedented move is being triggered by concerns from the national energy market operator that South Australia’s world-leading take-up of solar panels is making the grid unstable.
The concerns, raised in an Australian Energy Market Operator (AEMO) report obtained by The Advertiser, include that solar systems can stop working after voltage disturbances – or sudden losses of power – which was one of the triggers for the 2016 statewide blackout.
The findings will prompt a $10 million state government investment to fund measures that will allow it to switch household solar on and off to stabilise the grid.
The measure would shore up stability of the grid to help avoid mass blackouts but would also cut revenue earned by the household feeding electricity back into the grid.
The concerns are raised even further because AEMO predicts household solar panels in SA could provide 100 per cent of the state’s energy needs on certain days within a few years.
But it says there is “considerable evidence that many distributed PV inverters (solar panel systems) disconnect in response to voltage disturbances” – similar to challenges faced by wind turbines during the 2016 statewide blackout.
It has raised concerns within government that if SA was cut off from the national electricity grid and large numbers of solar panel systems failed, the state could be again plunged into a blackout.
The statewide grid relies on a mix of reliable energy sources, more volatile intermittent renewable energy including solar, and baseload gas.
New rules, which The Advertiser understands will be announced Friday, mean the market operator will have the ability to reduce solar panel outputs – stopping households pushing power back into the grid. New solar panel systems would also be able to be controlled by the market operator via smart meters.
“Analysis in this report demonstrates that a severe but credible fault (in the grid) near the Adelaide metropolitan area could cause disconnection of up to half the distributed PV (solar panels) in the South Australian region,” the report says. Government sources said the issue was incredibly serious, echoing the problems that led to the statewide blackout in 2016.
A loss of power from wind farms and tripping of the interconnector to Victoria combined to collapse the stability of SA’s network and deliver the statewide blackout, a 2017 AEMO report found. The government sources said commissioning of the report had probably saved a repeat of that incident.
There is already so much rooftop solar in South Australia that, at times AEMO struggles to securely manage the system. Figures from the Clean Energy Regulator show there are about 276,000 solar panel systems on SA homes – representing about 35 per cent of all dwellings in the state.
An estimated 11 per cent of small business and 24 per cent of large businesses have solar. Last year, there were times when 64 per cent of SA’s power use was from rooftop solar. The report said SA has already experienced dangerously low operational demand that is required to maintain a stable electricity grid.
Demand is expected to reduce further by spring, prompting AEMO to stress there is “an urgent need” to establish ways to increase more reliable system loads while decreasing the use of solar.