Load shedding

Electricity cannot be stored efficiently and so power generators must constantly supply the amount of electricity being used at any one time.

Electricity networks must safely deliver this electricity, so they too must be designed and built to match the amount of electricity needed by homes and businesses at peak times when demand for power can reach high levels.

On very few occasions, power stations or parts of the electricity network are not available or able to operate at maximum capacity when demand for power is high.

By sharing or rotating electricity supply to customers during these times, electricity distributors can avoid more widespread power outages, or potentially long lasting interruptions.

When load shedding is required, we make every attempt to ensure important customers such as hospitals and retirement homes have back up supply, such as portable generators. We also make every attempt to contact individual customers who may require continuous supply.

Turn off all power points, light switches, appliances and electronic equipment. This will reduce demand on the grid and provide greater safety when power is restored in your area.

Avoid using non-essential electrical appliances when you have power during the rotating event. Keep the big energy users like washing machines, swimming pool pumps, dishwashers, heaters or air conditioners turned off if possible.

Top tips

• Turn the fridge off and leave the fridge door closed as much as possible to keep food fresh. Consider putting the most commonly used items like milk and drinks in an esky or tub filled with ice. 
• If it's happening at night, leave a light turned on so you'll know when power in your area has been restored. 
• Have fresh batteries available for torches and radios. 
• Take care if you're using candles. 
• Keep an eye out for neighbours. This is especially important for the elderly, sick or those with young children. 
• If you have a gas barbeque, keep the gas bottle full. You can still cook and make hot drinks. 
• Remember if you have gas hot water or a gas stove you can still shower and cook.
• If you are feeling unwell, contact friends, family or a doctor for help, or relocate to an area with power. Many major clubs and shopping centres have generators so can provide respite from the hot or cold weather during outages. 
• Take care when driving as traffic lights may be affected by power interruptions.

Over the past decade, there has been no major load shedding event on the Ausgrid electricity network. On February 3, 2011, power was switched off on a rotating basis to about 1,000 customers for one hour intervals during the evening peak periods in parts of Enfield in Sydney’s Inner West. This was required because cable faults limited supply from the local Enfield Zone Substation at a time when demand for power hit record levels for consecutive days during extreme hot weather.

Other examples of power sharing, rotating outages or load shedding around the world include:

Texas: In February 2011, customers in Texas and New Mexico were affected by load shedding following unexpected problems on more than 50 power plants across Texas during a period of record cold temperatures. Each blackout was experienced by 330,000 people for on average less than 45 minutes at a time.

In April 2006, customers in Middle and South Texas experienced load shedding after unexpected high temperatures.

California: In August 2005, more than 500,000 customers in Southern California experienced rotating outages following a transmission line failure which coincided with higher than expected temperatures leading to high demand for power.

France: In December 2009, two million people in south east France experienced load shedding following network problems which coincided with lower than average temperatures.

Adelaide, Australia: Power was interrupted to 95,000 customers in Adelaide on a rotating basis on January 29, 2009 because of a lack of supply on a 43 degree day. The electricity transmission network operator was ordered to shed load by the electricity market operator because a transmission link between Tasmania and Victoria shut down.

NSW South Coast: Load shedding has also occurred on the NSW South Coast in 2006.

Ausgrid undertakes accurate load forecasting and invests efficiently in its network. This includes an $8 billion investment program and the delivery of about 1,000 maintenance tasks every day.

As a result load shedding is a very rare occurrence.