Why the backstop exists
On mild, sunny days with low demand, rooftop solar can supply so much of a state's electricity that there is too little demand left for the grid to stay stable. AEMO calls these minimum system load events. If nothing else works, briefly reducing rooftop solar keeps the system secure and avoids a much bigger outage.
Governments present it as the price of connecting more solar safely. The NSW Government describes it as a last resort that will only be used to keep the lights on if nothing else is working.
Where the backstop applies
| State | From | Applies to |
|---|---|---|
| South Australia | 28 September 2020 | New and upgraded solar systems, through an appointed relevant agent |
| Western Australia | 14 February 2022 | New and upgraded systems with inverters of 5 kVA or less |
| Queensland | In place | New solar connections under network connection rules |
| Victoria | 1 October 2024 | New, upgraded and replacement systems up to 200 kW (larger systems from 25 October 2023) |
| New South Wales | Staged from late 2026 | New and upgraded systems up to 200 kW, with CSIP-AUS compliant inverters |
What it means for your system
A compatible inverter
New systems need an inverter that can be managed remotely. In NSW this means meeting the CSIP-AUS standard.
An internet connection
The inverter must stay connected so it can receive a signal. Keep your Wi-Fi details up to date with your installer.
Registration
Your installer registers the system with the network or an approved agent, depending on the state.
How often is it used?
Rarely. It is reserved for emergencies declared by AEMO, and lasts only as long as needed. When it is used, homes still draw power from the grid, they just lose some or all of their solar output for that period.
Common questions
If your system was installed or upgraded under backstop rules in your state, yes, but only as a last resort when AEMO declares an emergency. Your supply from the grid stays on.
No. It applies to new, upgraded or replaced systems from each state's start date. Existing systems are not affected unless you change them.
For new systems covered by the backstop, yes. The inverter must be connected so it can receive a signal in an emergency.
Sources
Every rate on this page comes from the regulator or the regulated retailer. Last checked October 2026. Prices include GST unless we say otherwise.