Australian grid operator announces curtailment drill for rooftop PV

SA Power Networks, the electricity distribution network operating in the state of South Australia, has announced its annual curtailment test will take place next Tuesday (August 25).

A statement published on the network’s website describes the annual test as “like a fire drill for the grid” that ensures its ability to temporarily curtail rooftop solar generation.

“[The test] simulates a rare but urgent situation so we can confirm that all systems and people are ready to respond if an actual emergency occurs,” the statement adds.

Around 100,000 customers are expected to be impacted on the day, with the curtailment expected to last less than an hour. SA Power Networks says solar systems will ramp down to 0 kW before ramping back up, with customers expected to miss around 1.5 kWh of generation on average.

The network’s update explains that the Australian Energy Market Operator (AEMO) can direct it to use curtailment to help keep the electricity system stable during a system security emergency. 

“AEMO monitors grid stability nationally and works to maintain system security – balancing electricity supply with demand,” the statement continues. “In South Australia, that balance can be challenging because we have more rooftop solar per capita than almost anywhere in the world.”

The government of South Australia passed legislation in 2020 requiring all solar systems installed after September that year to be able to be remotely disconnected during a system security emergency.

Curtailment is considered as one of the biggest challenges facing the development of Australia’s solar market, across all market segments. Analysis from February found South Australia typically sees relatively moderate curtailment through autumn and winter followed by a sharp escalation in spring and early summer.

Earlier this year, the Australian Energy Market Commission unveiled plans to modernize its distribution network planning, which it says will help to lower curtailment of rooftop solar.

According to figures shared by the International Solar Energy Society, the number of dwellings with rooftop PV in South Australia has now passed 50%.