South Australia recently hit a record for the lowest electricity demand, dropping to -205 MW on October 19, 2024, at 1:00 PM. This happened because the weather was mild, the skies were clear, and a big power user was offline. At that time, solar panels on homes and businesses produced 114% of the electricity needed, with extra power sent to Victoria. Every year, South Australia’s electricity demand is dropping by over 100 MW on average, and this trend is expected to continue. To handle this, the SA Government and SA Power Networks have put plans in place to manage extra solar power and keep the electricity system stable.

South Australia’s electricity system has certain limits that must be followed to keep it running smoothly. These limits change over time as technology improves and better planning tools become available.

Electricity Demand Levels in South Australia

If electricity demand in South Australia falls too low, there can be problems sending power to Victoria. The safest level of demand is between -520 MW and 400 MW, depending on which power plants are running and whether there are any power line issues. The lowest limit (-520 MW) assumes only the smallest necessary power plants are running. The highest limit (400 MW) applies if several power lines or power plants are out of service.

If South Australia is at risk of being disconnected from the national grid, the Australian Energy Market Operator (AEMO) does not allow planned power line work if demand is expected to drop below 250 MW. If demand goes lower, emergency actions may be needed to keep the power flowing.

When South Australia is Disconnected

If South Australia is cut off from the national grid, at least 400 MW of electricity demand is needed to keep the system stable. This number can sometimes be as high as 600 MW, depending on which power plants are running and how much energy storage is available.

Because so many homes and businesses in South Australia use solar power, it is important to control how much electricity is being generated and used. If there is too much solar power and not enough demand, it can cause problems with frequency and voltage in the grid. Normally, at least 400 MW of electricity demand is needed, but under some conditions, it can go up to 900 MW.

As shown in the data, South Australia’s electricity demand has already dropped below some of these safe levels. This means emergency actions have been needed to keep the system stable, especially when South Australia is disconnected from the national grid or if power line limits are affected.

Emergency Actions Taken

On November 13-19, 2022, South Australia was cut off from the national grid for a week due to storm damage. To keep the system stable, AEMO told SA Power Networks to make sure at least 715-855 MW of demand was maintained. This meant some solar power had to be turned off. On some days, SA Power Networks had to use their full ability to manage the situation.

On 15 February 2024, after a big storm damaged six power towers, South Australia was at risk of losing connection to the main power grid. To prevent problems, some solar power systems had to be turned off. There are certain rules in place to make sure the power system stays safe when demand for electricity is low.

Some important changes have helped keep the system stable. New machines called synchronous condensers were installed, and fewer power units are now needed to keep the system running. Experts also understand more about how to manage electricity in South Australia. New battery storage systems help provide extra power quickly when needed, and new rules have improved how solar systems follow safety standards.

By 2026, South Australia’s electricity demand is expected to drop to very low levels, meaning backup power will be needed more often. A project called EnergyConnect will help send more power out of South Australia, but at the same time, other areas may also have low demand. This could make it harder to send extra electricity away when needed.

South Australia will need more backup power in the coming years. In October 2023, about 426 megawatts (MW) of backup was needed. By October 2024, it is expected to rise to 697 MW, and by October 2025, it may reach 857 MW. This backup is important to make sure there is at least 400 MW of electricity demand to keep the system running safely.

There are different ways to provide this backup power. Since 2017, larger solar power sites have had special controls installed so they can be turned off if needed. By early 2024, these systems could produce up to 204 MW of power, but they usually generate less when electricity prices are low.

Since 2020, new solar systems in South Australia must be able to be turned off and back on by a remote operator. There is also a Flexible Exports system that allows customers to send more electricity to the grid when possible. This system automatically adjusts to lower levels when needed for safety.

Another way to control the system is by changing voltage levels in power networks. This process, called Enhanced Voltage Management, helps keep the power system balanced. If voltage gets too high, some solar systems automatically switch off, which can be used as a last resort to keep the grid safe.

All these methods help South Australia manage its power system during times of very low demand. Improvements in how backup power is controlled are still being worked on. There is an ongoing effort to make sure these systems are reliable and can keep the electricity network safe and stable.

Emergency Backup Power in South Australia

South Australia is working on improving its backup power. In 2023, it had around 42 MW of extra power available. By 2024, this increased to about 89 MW, and in 2025, it is expected to reach 109 MW. Flexible power limits started at 0 MW in 2023 but are expected to grow to 119 MW by 2025.

More power sources, called Relevant Agents, added 206 MW in 2023, increasing to 251 MW in 2024 and 252 MW in 2025. Another method called Enhanced Voltage Management stayed the same at 300 MW each year. The total backup power grew from 548 MW in 2023 to 665 MW in 2024 and is expected to reach 780 MW in 2025.

Referring to the figure above, the amount of power needed is also increasing. In 2023, 426 MW was needed, but this jumped to 697 MW in 2024 and could reach 857 MW by 2025. This means South Australia still does not have enough backup power, and by October 2024, there could be a shortage of 33 MW. This shortage is expected to grow, so fixing this problem is urgent.

What Is Being Done?

Steps are being taken to fix the shortage. SA Power Networks is making sure Flexible Exports work well and setting up systems to check and enforce power rules. This includes making sure emergency power is available and that power systems can handle sudden changes.

SA Power Networks is also working to make sure that when backup power is needed, it can be provided quickly—ideally in less than 10 minutes. ElectraNet is making sure that power transmission can handle low-demand periods and possible outages. They are also investing in new technology to improve voltage control.

Different ways to provide essential power services are being explored, especially for times when there are outages or low demand. A big project called EnergyConnect is also being set up to help improve power stability.

AEMO, the group that manages electricity, is working to set clear rules for how much power is needed in normal conditions. They are also updating their plans for what to do if South Australia gets cut off from the rest of the electricity network.