We're just two weeks into winter and the season has already proven to be a trying one.
The Australian Energy Market Operator (AEMO) has made the decision to suspend the spot market for wholesale electricity.
With multiple ways the operator can keep the system stable, load shedding is the most extreme one.
In the case of load shedding, we take a look at who decides when the electricity goes off and to which areas.
How is an area's power disconnected?
Areas are disconnected from the power supply by distributors switching off the feeder serving that area.
Think of a distributor as "poles-and-wires" company, and a feeder as a high voltage power line.
Which feeders get switched off depends on a number of factors:
- Where the area sits in the state or territory's priority order of load shedding
- How much power needs to be saved
- Which areas are using the most energy
Who decides whose power gets disconnected?
There are two big names to note here.
First, Australia's electricity market is overseen by independent organisation, AEMO.
And second, Victoria is part of the National Electricity Market (NEM) which connects Queensland, New South Wales, South Australia, the ACT and Tasmania.
This means electricity can be generated in these states and transported to Victoria via transmission lines.
AEMO decides when load shedding is needed in the NEM.
But it does not decide which areas are shed.
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Instead, AEMO works closely with the electricity industry to minimise the impact on the community, particularly major health facilities, emergency services and public transport.
How is this decided?
According to CitiPower, networks carefully pre-identify the priority list of feeders to be shed.
This allows them to quickly turn off power when directed by AEMO.
To prepare for the event of load shedding, networks annually review the types of customers connected to each feeder across their networks.
They then determine which areas should be considered high priority based on where critical customers are located.
Generally, the first areas to be turned off are residential.
Critical customers are the last to have their power turned off and the first to have their supply restored.
This may not always be possible depending on how much electricity AEMO directs networks to shed.
Approaches vary between states and territories.
Distributors try to minimise the impact of load shedding by rotating the disruptions between different areas.
How do I know if my power will be switched off?
There's no exact answer.
The amount of notice networks are able to provide during a load-shedding event depends on the direction of AEMO.
Typically, most networks provide updates during outages via text message, their website or customer contact centre.
Does living near a hospital or smelter affect your chances of being cut off?
Feeders serving hospitals are less likely to be disconnected. However, being located near a hospital doesn't necessarily mean you share its feeder.
Living near a big industrial energy user is unlikely to have any bearing on whether you lose power either.
CitiPower says facilities often choose to have their own emergency generation equipment available, so they can operate independently of the network when required to.
