Emergency backstop mechanism

Requirements for new and replacement rooftop solar and battery storage systems of 10 kilovolt amperes and over.

Adapting to Queensland’s changing electricity system

Queensland is a world leader in rooftop solar PV (photovoltaic) uptake and is naturally positioned to continue this trend.

As more renewable energy is integrated into the grid, we need to ensure the electricity system remains secure so all Queenslanders can continue to depend on it.

To enable individual customers to feed their solar energy into the grid at growing rates, the Queensland Government introduced an additional safeguard to maintain electricity system reliability if there is a threat to the safe delivery of power to customers.

Queensland’s emergency backstop mechanism

All new and some replacement inverter energy systems (like rooftop solar PV), with aggregated capacity of 10 kilovolt amperes (kVA) and above are required to be fitted with a generation signalling device. Some exclusions apply to the requirement – including inverter energy systems where the inverter is solely supplied by a battery.

This device enables Ergon Energy and Energex to reduce the risk of state-wide power outages by switching these systems off for a short time in an energy emergency situation.

The ‘emergency backstop mechanism’ will be activated only as a last resort at the direction of the Australian Energy Market Operator (AEMO). The decision will be in line with AEMO’s minimum system load market notification framework, which sets out pre-agreed steps and actions that AEMO can issue to electricity networks in response to a declared energy emergency.

This is an important step in supporting Queensland’s transition to a more coordinated electricity system, as it will:

allow more households and businesses to enjoy the benefits of rooftop solar in the future
support the uptake of technologies like battery storage and electric vehicles.

Electricity networks operate at their best when supply aligns with customer demand. When solar generation is high and demand falls too low, it poses a risk to system security.

This makes it more challenging for Queensland’s network service providers (Powerlink, Energex and Ergon Energy) to supply power to Queensland homes and businesses safely and reliably.

When this occurs, it is called a ‘minimum system load’ event. The emergency backstop mechanism will mean our distribution networks can continue to connect solar at the same impressive rates as recent years, without affecting the safe and reliable supply of power to all customers.

National recommendations

In July 2024, the Energy and Climate Change Ministerial Council released the National Consumer Energy Resources Roadmap recommending each jurisdiction implement a backstop capability that is robust and reliable. This action is intended to enhance the emergency response system and, in doing so, improving operational security for all consumers.

The Queensland Government is currently exploring ways to enhance Queensland’s emergency backstop mechanism.

New solar PV connection requirements

Currently all new and some replacement inverter energy systems (like rooftop solar PV), with aggregated capacity of 10kVA and above are required to be fitted with a generation signalling device to connect to the grid.

The generation signalling device is activated via Energy Queensland’s audio frequency load control (AFLC) network. The AFLC network allows for a signal to be transmitted across the state’s electricity system. Exclusions apply to the requirement to install a generating signalling device – including where inverter energy systems are installed at a location that is not serviced by the AFLC network.

AFLC has been utilised by Queenslanders for almost 70 years and is proven to support system security. Energex and Ergon Energy also use the AFLC network to operate economy tariffs (mainly for hot water load control) and the PeakSmart program, which dials down air conditioners during peak demand events.

In an energy emergency situation, AEMO would direct Energex and Ergon Energy to turn inverter energy systems off (via the AFLC network), preventing any generation, self-consumption or export for the duration of the event to maintain security of the grid. Some exclusions apply – including inverter energy systems where the inverter is solely supplied by a battery.

Find out more about how AEMO | Fact sheet: Minimum system load (MSL) and lets the market know when it needs to act.

Information for customers

Customers looking to install rooftop solar and battery systems should always source quotes from reputable suppliers (see the Clean Energy Council website).

Information for solar retailers and installers

The requirement for new and some replacement inverter energy systems (like rooftop solar), with aggregated capacity of 10kVA and above to be fitted with a generation signalling device is reflected in the Queensland electricity connection manual (PDF, 21.57MB) and connections standards:

Solar retailers and installers should contact Ergon Energy or Energex for further information about accessing and installing the generation signalling devices.

Contacts

Queensland Treasury (general enquiries) - 13 43 87
Energex (installer enquiries in South East Queensland) - 13 12 53
Ergon (installer enquires in regional Queensland) - 13 74 66

Last updated: 15 February 2025