Load shedding

AEMO makes the decision to load shed. They tell us how much the demand needs to be reduced by, and we respond by switching power off in different areas across our network for short periods of time. In most instances, we receive these instructions at very short notice.

Power outages related to faults on our local network infrastructure can happen for a range of reasons, including extreme weather, vegetation coming into contact with our network, wildlife and car accidents. In these cases, the causes are accidental and the impacts are usually localised.

In load shedding, power will be turned off due to an enforced action by the Australian Energy Market Operator (AEMO). This is outside our control and the impacts can be on a wider scale.

Load shedding incidents are much rarer than power outages related to faults.

In any case, our employees based in our control centres and depots respond to restore power as safely and quickly as possible.

When directed to load shed, our aim is to minimise the impact to the community and to keep areas with critical infrastructure such as major hospitals, sewerage and water pumping stations and major public transport on supply.

The first areas to be turned off during a load shedding event will be mainly residential in both metropolitan and regional areas.

Typically, critical customers are last to have power turned off and first to have supply restored. This may not always be possible depending on how much electricity AEMO directs us to shed.

To prepare for the rare event of load shedding, we annually reviews the types of customers across our network. Our team then determines which areas should be considered high priority based on where critical customers are located.

If we don’t act in time, power may be cut at a transmission level and this is likely to impact more customers for longer periods of time. As a result, the system may completely shut down and widespread blackouts may occur. This is known as a ‘system black’ and it can take hours or days to restore power to all customers.

During a load shedding event, your power supply is typically interrupted for one to two hours. It’s then reinstated as power supply to other customers is interrupted. We seek to minimise the impact to customers by rotating these outages, but it is possible customers will be impacted more than once if an event continues for a number of hours. These rolling outages will continue until AEMO directs us to restore power.

During load shedding events, localised network faults can still occur and cause outages. This may mean customers are without power once the load shedding event is over. In these cases, our crews will be working as safely and quickly as possible to identify these faults and restore power to those customers.

Every load shedding event is different and the number of customers impacted will depend on how much demand AEMO needs to reduce to ensure balance on the grid. Generally, the higher the electricity demand that needs to be reduced, the larger the number of customers impacted.

Importantly, by load shedding on a rotational basis, lengthy and widespread blackouts can be prevented.

Due to the design of our network, it’s not possible to isolate and exempt individual customers when shutting off large feeder areas. By load shedding on a rotational basis, we aim to minimise the impact to customers.

Some critical customers such as major hospitals, have their own dedicated feeder line and can be unaffected by load shedding. Other facilities choose to have their own emergency generation equipment available so they can operate independently of the network when needed.

The decision to buy a generator is up to individual homes and businesses. Load shedding is highly unusual, however power outages can happen for other reasons such as extreme weather events, car accidents or equipment failure. It’s for that reason we encourage businesses that depend on electricity to have a back-up plan, such as a generator, in case there is an unplanned outage.

Demand response programs play a role in reducing the amount of electricity being used during peak times. As a network business, we have demand response programs on localised areas of our network. Whether this is sufficient in a load shedding event depends on instructions from AEMO.

For planned outages initiated by us, we communicate directly with all customers including those who rely on electricity for life support equipment.

During a load shedding event, it is unlikely we could selectively keep power on to individual customers, including life support customers.

We always recommend that life support customers have an action plan in place in case they experience an interruption to their power supply. We also ask our life support customers to ensure their contact details are up to date in our records.