Victorians have embraced taking control of their energy bills and their emissions, with rooftop solar uptake across the state having soared. Rooftop solar provides real savings for households and businesses and reduces Victoria’s greenhouse gas emissions – but the high uptake of solar can lead to system security challenges such as minimum system load.
Minimum system load is defined as the lowest demand on the grid on any given day, week or year. Minimum system load typically occurs when demand from the grid is low and the output from solar is very high – such as on mild, sunny days on weekends and public holidays (expected particularly in spring when the weather is sunny but usually more mild, requiring households to use less electricity)
When our solar exports are high, but our energy use is low, the electricity grid can exceed safe operating parameters. This can lead to a minimum system load emergency which is rare but has the potential to lead to local or state-wide blackouts.
Victoria is introducing an emergency backstop mechanism to manage this risk. The emergency backstop will mandate capabilities to remotely curtail new and replacement solar systems as a last resort to manage minimum system load emergencies and protect Victoria’s system security.
What is the Solar Emergency Backstop?
Victoria’s emergency backstop mechanism for solar is designed to ensure energy reliability as the state transitions to renewable energy, particularly solar power. As solar generation can fluctuate due to weather or time of day, the backstop mechanism is critical for preventing blackouts and maintaining grid stability. This backstop includes a combination of energy storage, demand management, and grid resilience measures.
The solar emergency backstop is a mechanism that allows electricity distribution businesses like AusNet to remotely turn down or switch off rooftop solar systems during an energy supply emergency. This is only used as a last resort to avoid widespread power outages. This change has been mandated by the Victorian Government.
Why do we need an emergency backstop?
Occasionally on mild sunny days, when demand is low, there is more solar generated electricity being exported to the grid than we can use.
This can lead to
- Unstable electricity supply
- Low voltage issues
- Possible outages
To overcome this and to support more households installing solar, there is a need for an emergency backstop. This backstop will ensure solar exports can be safely managed by enabling rooftop solar systems to be turned down or switched off when there is too much power in the grid.
The backstop will be a last resort and will not affect the supply of electricity to the home. It will only be used when required by the Australian Electricity Market Operator (AEMO) and only as long as it is needed, anticipating rare emergencies when solar exports are too high to be safely managed.
This comes into effect from the 1st of October 2024 for all new small and medium installations or those undergoing an upgrade. To ensure that a system is backstop enabled a compatible inverter is installed to a reliable internet connection enabling the distributor to communicate with the inverter.
Key Components of Victoria’s Solar Emergency Backstop:
1. Battery Storage Solutions
- Victorian Big Battery: One of the largest grid-scale batteries in the Southern Hemisphere, this 300 MW/450 MWh battery plays a critical role in the state's energy backstop strategy. It stores excess solar energy generated during the day and dispatches it during peak demand periods or when solar production is low.
- Distributed Battery Storage:Through programs like Solar Victoria, households and businesses are incentivized to install solar batteries. These smaller, decentralized storage systems act as mini power plants, reducing grid strain during emergencies and increasing energy resilience.
- Pumped Hydro Storage Victoria is also exploring pumped hydro projects to complement battery storage, providing another reliable source of energy backup.
2. Demand Response Programs
- Virtual Power Plants (VPPs) : Victoria is fostering the development of virtual power plants, which aggregate solar and battery systems from homes and businesses into a single dispatchable resource. This allows energy retailers and operators to draw power from distributed solar systems during grid emergencies.
- Demand Management Victoria employs demand-side management strategies that reduce electricity consumption during peak times. This includes encouraging large consumers and households to shift their usage patterns and use smart appliances to reduce demand when solar power is insufficient.
3. Grid Modernization and Integration
- Smart Grid Technology : Victoria is investing in smart grid technology to improve energy flow management and ensure solar power is effectively integrated into the grid. This technology allows for real-time monitoring and adaptive control of electricity distribution, making it easier to balance supply and demand.
- Network Upgrades : The state's energy infrastructure is being upgraded to handle the intermittent nature of solar power. This includes stronger interconnections with other Australian states through the National Electricity Market (NEM), allowing Victoria to import power when local solar and renewable energy supplies are low.
4. Market Reforms and Emergency Protocols
- Five-Minute Settlement Rule : This market reform allows for faster and more accurate dispatch of energy, improving the grid's ability to respond to sudden drops in solar generation. It helps encourage quick-start technologies like battery storage and peaking gas plants to fill the gap when solar production dips.
- Capacity Mechanism (Proposed) : The Australian Energy Market Operator (AEMO) is considering the introduction of a capacity mechanism, which would require energy providers to guarantee a certain amount of backup capacity (such as batteries, gas, or hydro) in the event of solar shortfalls.
5. Renewable Energy and Hybrid Systems
- Hybrid Renewable Projects : Victoria is also developing hybrid solar and wind farms, where solar and wind energy generation are combined on the same site. This helps balance the variability of solar production, as wind energy tends to be more available at night or during cloudy periods when solar production is low.
- Green Hydrogen Storage : Victoria is exploring the potential for hydrogen energy storage, which can store excess renewable energy (including solar) in the form of hydrogen, to be converted back to electricity when needed.
6. Emergency Energy Reserves
- Reserve Trader Mechanism : In extreme circumstances, AEMO can activate its Reserve Trader Mechanism, contracting additional energy reserves from generators or large consumers willing to reduce their load during a shortfall in solar or other renewable energy.
- Gas Peaker Plants: While Victoria is moving away from fossil fuels, gas Peaker plants still serve as a last-resort backup during solar energy shortages. These plants can ramp up quickly to provide electricity when solar generation falls short.
Victoria is actively addressing the challenges posed by increasing solar capacity by combining energy storage, regulatory reforms, and large-scale infrastructure projects designed to ensure a stable and reliable grid.
Introduction timeline
The emergency backstop will be introduced in 2 stages for newly installed, upgraded and replacement rooftop solar system.
Stage 1 – Large solar systems
From 25 October 2023, an emergency backstop applies to all new, upgrading and replacement solar systems greater than 200 kW (large).
Distribution businesses have introduced emergency backstop capabilities for new and replacement solar systems connecting to their networks. Your distribution business can provide more information about these requirements when you apply to connect or replace a large solar system.
Stage 2 – Small and medium solar systems
From 1 October 2024, an emergency backstop applies to all new, upgrading and replacement rooftop solar systems less than or equal to 200 kW (small and medium). For these rooftop solar systems, this means the power you generate and feed into the grid can be remotely turned down or switched off in an emergency, as a last resort.
What happens if my solar inverter loses internet connectivity?
If your solar inverter loses internet connectivity, the excess energy you export to the grid will automatically be reduced. This ensures it can be safely managed.
- If the internet outage is temporary, your exports will return to normal once the internet is reconnected
- If your inverter is disconnected from the internet, potentially because of a change to your Wi-Fi password, then you will need to reconnect it to the internet to ensure you can continue to export your excess solar power to the grid. You can usually do this through your solar inverter smart phone application or the display. Your solar installer should show you how to reconnect your inverter if it disconnects from the internet
What do I need to do?
If you are installing or upgrading your rooftop solar system after 1 October 2024, your installer must ensure it is emergency backstop enabled. This requires:
- A compatible inverter : This means the export and generation from the inverter can be remotely managed.
- A reliable internet connection : This will ensure the distribution business can communicate with the inverter. If you do not have rooftop solar, or you have an existing rooftop solar system installed before 1 October 2024, then these changes will not impact you.
Conclusion
Solar Backstop Mechanism in Victoria highlights its role as a safeguard for solar energy consumers, ensuring that they can continue to receive fair compensation for exporting excess energy to the grid, even during periods of network congestion. This mechanism protects solar households from financial losses due to curtailment, encourages further investment in grid infrastructure, and supports the state’s broader transition to renewable energy.
By addressing the technical challenges of grid capacity, the backstop mechanism fosters sustainable growth in solar adoption, ensuring that Victoria’s energy system can evolve in harmony with increasing renewable energy generation. Overall, it’s a crucial measure for balancing consumer protection, grid stability, and the state’s clean energy goals.