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What is a Minimum System Load (MSL) event?
Victorians are investing in rooftop solar at record levels, driving down energy bills and day-time wholesale energy prices.
On occasion – most likely mild, sunny weekends or public holidays when consumers are outside enjoying the weather – less energy is being used by households and businesses than is being generated, sending excess rooftop solar into the grid.
This combination of very low energy use and high solar energy generation can lead to a period of instability in the grid which is called a Minimum System Load (MSL) event.
The Victorian Government, in collaboration with the Australian Energy Market Operator (AEMO), has processes in place to manage these events in a transparent and coordinated manner to protect Victoria’s system security.
What happens in a MSL event?
In an MSL event, the Australian Energy Market Operator has established protocols with multiple actions to avoid disruptions to Victoria’s electricity supply.
AEMO’s MSL protocols include 3 levels of escalating actions, starting with:
- increasing Victoria’s electricity exports to other states
- constraining (reducing) wind and large-scale solar generation and
- directing batteries to charge and recalling maintenance of key assets.
In addition, under rare and extreme circumstances, household generation can be curtailed without impacting power supply to households or businesses via Victoria’s emergency backstop mechanism.
This mechanism allows AEMO to direct electricity distribution businesses to remotely turn down or switch off generation from new, upgraded or replacement rooftop solar systems less than or equal to 200 kW installed since 1 October 2024, or systems larger than 200kW installed 25 October 2023.
What do I need to do in a MSL event?
The best thing households and businesses can do on any day – but especially during a MSL event – is to save money by using your rooftop solar power during the day.
The top 5 ways you can use your solar energy during daylight hours are to:
- Charge your electric vehicle
- Use your oven and/or dishwasher
- Use your washing machine and dryer
- Run your pool pump
- Charge your home battery
Page last updated: 20/12/24