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Western Australia’s clear blue skies and plentiful sunshine mean that households and businesses are installing rooftop solar PV systems at a faster rate than ever before. 

Over 36% of homes in the South West Interconnected System (SWIS) now have solar and while this is great news for the environment, the energy system was not built for a two-way flow of energy, from energy generation sources to consumers, and from consumers to the energy system, such as energy generated from household energy assets like rooftop solar systems. 

Increasingly, as more systems are installed, excess solar energy is flowing into the energy system and impacting the security and reliability of our energy system. 

The reliability of the energy system requires the supply and demand of electricity to be balanced. A significant challenge right now is managing energy system security during times when customer demand for electricity from the energy system, known as ‘load’, is very low.  

On mild, sunny days, the energy output from rooftop solar is high. If customer demand for electricity from the energy system on these days is too low, the system can be at increased risk of blackouts.  

The accelerated uptake of rooftop solar PV has increased the urgency of measures to address ‘low load’, and it is contributing to the emergence of new energy system challenges. If left unmanaged, these low load events will place the WA energy system at increased risk of outages.

One of the methods of managing low load is called emergency solar management, also sometimes referred to as curtailment. 

Learn more about emergency solar management, how it can help manage low load and what would happen if low load is left unmanaged. 

What is emergency solar management? 

Emergency solar management is a measure to maintain the reliability of the energy system and support the continued installation of rooftop solar. Emergency solar management is the ability to turn down or turn off the capability of rooftop solar systems remotely.

The WA Government introduced this capability for new and newly upgraded rooftop solar systems as a last resort measure to be used only in emergency operating conditions created by low load.

What happens to managed systems during a low load event?

Just like only watering your garden on certain days, or taking reusable bags to the supermarket, emergency solar management will help maintain our shared resources for the good of the community and the environment. 

The WA Government’s requirements for the management of rooftop solar only apply to new and upgraded rooftop solar systems in the South West Interconnected System (SWIS) with an inverter capacity of 5kVA or less. This means that customers with existing rooftop solar systems installed prior to the introduction of emergency solar management are not be affected by the requirements and do not need to do anything. 

Output from residential rooftop solar systems will only be reduced as a last resort in extreme circumstances to ensure excess solar energy is not being exported to the energy system. This will help to maintain the security of the energy system and prevent blackouts during extreme low load events. In these circumstances, households will draw electricity from the energy system, rather than their solar system. 

In the SWIS, these events (and therefore the need for emergency solar management) are expected by Energy Policy WA (EPWA), the State Government’s energy policy agency, to occur infrequently and for short periods.

In South Australia, which has more rooftop solar installed than Western Australia, but has the benefit of interconnection with other states in the National Electricity Market, emergency solar management has been used only once since it was introduced in 2020.

What happens if we don’t manage solar output?

Emergency solar management is a tool that will help ensure our energy system remains reliable, so we can continue to enjoy an uninterrupted supply of electricity to power our lives – at work, at school and at home.

Without the ability to manage rooftop solar in extreme low load situations, the only response available to energy system operators is to cut electricity, resulting in blackouts.  Suburbs with the most rooftop solar output would likely be cut off first.  

Having the ability to sensibly manage rooftop solar output to manage extreme circumstances will help keep the lights on for everyone and allows Western Australians to keep installing rooftop solar systems.

A positive solar future

With WA’s positive shift to renewable energy sources such as rooftop solar, our energy system can be challenged by low load events that could lead to instability and blackouts.

New emergency solar management measures will help remotely regulate rooftop solar output, to ensure our energy system remains reliable and secure so the lights stay on for everyone.

To stay informed, read our emergency solar management FAQs for more information.