Annual Smarter Homes Solar Curtailment Test
On Tuesday 19 August, you may notice that your solar photovoltaic (PV) system stops generating or exporting energy for a short time - usually an hour or less.
SA Power Networks is conducting its annual test of our ability to temporarily curtail rooftop solar generation. This is a capability we may be directed to use by the Australian Energy Market Operator (AEMO) to help keep the electricity system stable during a system security emergency.
Why we’re testing
This once-a-year exercise is like a fire drill for the grid. It simulates a rare but urgent situation so we can confirm that all systems and people are ready to respond if an actual emergency occurs.
AEMO monitors grid stability nationally and works to maintain system security — balancing electricity supply with demand. In South Australia, that balance can be challenging because we have more rooftop solar per capita than almost anywhere in the world.
Sometimes, when rooftop solar exports are very high and electricity demand is very low, the grid can become unstable. SA Power Networks is delivering a range of innovations to manage this challenge, but we must still be prepared for unlikely events that could put the grid at risk.
What we’re checking
If AEMO directs SA Power Networks to act, it may have to happen at a moment’s notice.
We need to be sure that:
- Solar systems installed after September 2020 are compliant.
- Third parties known as Relevant Agents, who are responsible for disconnecting and reconnecting systems, can respond quickly.
- All systems reconnect smoothly once the emergency is over.
If compliance or responsiveness is lacking, more severe measures may be needed in a real emergency. This test helps confirm we can rely on the Smarter Homes capability.
A real-world example
In November 2022, a severe storm “islanded” South Australia from the rest of the national grid when the interconnector to Victoria failed during a period of surplus energy export. Thanks to the Smarter Homes capability, we were able to help maintain system stability for South Australian customers. You can read about the event here: SA Islanding: Managing solar on the island - WattClarity.
How curtailment works
If AEMO forecasts a risk to system security and has already used all other available controls, it can direct SA Power Networks to increase operational electricity demand. The fastest way to do this is by temporarily reducing rooftop solar generation. If this is not done, the imbalance could lead to widespread power outages.
To make this possible, the SA Government passed legislation in 2020 requiring all new solar systems (installed after September 2020) to be able to be remotely disconnected during a system security emergency. This functionality — included in the Smarter Homes regulations — is what we are testing today. You can read more about Smarter Homes here: Regulatory changes for smarter homes Energy & Mining
What customers can expect today
- Number of customers involved: Around 100,000.
- Timing: Less than one hour of curtailment, chosen for a day with moderate solar output to minimise impact.
- Impact: Systems will ramp down to 0 kW, then ramp back up. On average, customers will miss about 1.5 kWh of generation.
- After the test: For any systems that curtailed or reconnected too slowly (or not at all), we’ll work with agents and manufacturers to improve performance.
What do you need to do?
The test will be complete by sunset today (19 August). Most customers will not notice that the test is being conducted. If you want to confirm that your system has returned to normal, check your inverter screen or your mobile app the day after the test (20 August).
If you’re concerned that your system has not come back on, or if you are unsure, contact your solar installer or inverter manufacturer. We’ve already informed installers and manufacturers about this test.
What happens next
Our goal is to contribute to measures that keep electricity demand and supply in balance while supporting South Australia’s transition to more renewable energy. Maintaining system robustness and reliability is essential. These tests are infrequent, and we work to minimise both cost and inconvenience for customers.