The Australian Energy Market Operator (AEMO) manages and maintains the national electricity grid, balancing supply (electricity generation) with customer demand (load).
One of AEMO’s key jobs is to ensure the integrity and stability of the electricity grid. At times, rapid shedding of customer load is required to avoid even wider loss of supply or even a grid shutdown. This process is called Load Shedding.
At other times when the State is experiencing grid security issues due to high rooftop solar generation and low energy demand AEMO may direct SA Power Networks to reduce the amount of solar generation being exported to the grid to help balance supply and load by increasing customer demand. During this process, we may be directed to turn off customer solar inverters. This process is called Solar Curtailment. This is not the same as load shedding.
Read more about Solar Inverter Settings and Solar Curtailment for Minimum System Demand Events.
Manual load shedding
When manual load shedding is required, SA Power Networks is directed by AEMO to action load shedding based on a pre-agreed rotational list administered by the SA Government’s Office of the Technical Regulator (OTR). Load shedding is applied in targeted areas for 45 minutes at a time, and rotated across South Australia to share the impact fairly across customers. Access the OTR’s rotational manual load shedding list below to see the order of where load shedding will be applied.
Lines supplying critical infrastructure and the CBD are exempt from rotational load shedding. These exemptions are determined by the OTR.
Read more about load shedding on the Department for Energy and Mining website.
What happens when load shedding takes place?
There are two main types of load shedding:
Equipment in the electricity grid automatically switches off to stabilise and protect the network. This is normally in response to a sudden and unexpected disruption of the stability of supply in the national electricity grid, such as occurred after the collapse of transmission towers (which led to the State-wide blackout on 28 September 2016).
When AEMO identifies (in advance) that demand is going to exceed all the available generation, it directs utilities like us to reduce load by turning power off to some areas to maintain balance in the national electricity grid.
It’s called rotational load shedding because the outages for customers are kept to about 45 minutes, with load shedding rotated between suburbs and regions.
Lines supplying critical infrastructure and the CBD are exempt from rotational load shedding. These exemptions are determined by the State Government Office of the Technical Regulator. You can see the load shedding list of groups and details of the most recent load shedding.
What can trigger load shedding?
A number of factors can cause an imbalance between generation and demand. For example:
- a sudden or unexpected loss of a generator, or a fault on a transmission line, impacting system stability or energy availability
- spikes in demand for power, often during extended heatwaves, causing demand to exceed available supply.
What should I do during an outage?
If your power goes off we recommend you turn off all appliances and leave a single light switch in the ON position so that you know when power has been restored. You can then turn appliances on gradually once the power returns. If appliances at your home, and your neighbours’ homes, all turn on as the power is restored it could put pressure on the network and make your outage last longer).
Read our tips on what to do and how to stay safe during an outage.