SA Power Networks to Test Emergency Solar Shutdown Capability

SA Power Networks is set to run its annual test of the state's rooftop solar curtailment system on 25 August in South Australia. The test will temporarily reduce generation and export from around 100,000 residential systems for less than an hour. This exercise is designed to confirm the network's ability to respond if the Australian Energy Market Operator needs to protect grid stability during a system security emergency.

Background to the Test

The distribution network operator has described the exercise as a fire drill for the grid, simulating a rare but urgent scenario in which the Australian Energy Market Operator directs SA Power Networks to reduce rooftop solar output to prevent instability. South Australia has one of the highest concentrations of rooftop solar per capita in the world, which can create periods when solar exports are high and electricity demand is low enough to threaten grid stability.

The Test Procedure

The test checks three things: that compliant systems can be remotely curtailed, that Relevant Agents can respond quickly, and that all systems reconnect smoothly once the test concludes. During the test, affected systems will ramp down to 0kW output before ramping back up, with the average participating household expected to miss around 1.5kWh of generation. SA Power Networks pointed to a real-world precedent for why the capability matters, citing an event in November 2022 when a severe storm disconnected South Australia from the rest of the National Electricity Market.

Implications for the Market

The curtailment test lands as rooftop and utility-scale solar output continues to expand across the National Electricity Market. Combined solar generation across the market rebounded 37% in July as wholesale prices stabilised. Federal policy is also widening the pool of solar capacity subject to similar market and grid integration mechanisms. Australia is set to expand its Small-scale Renewable Energy Scheme to cover solar installations up to 1MW, up from the current 100kW threshold. Most customers are not expected to notice the test, which SA Power Networks said would be completed by sunset and scheduled for a day of moderate solar output to minimise its impact. Any systems that curtail, reconnect too slowly, or fail to respond at all will be followed up with the relevant installer or manufacturer to improve performance ahead of any future emergency in which the capability is required.