Animals and electricity supply
Updated February 2021: Animals are involved in 6-7% of power outages on the distribution network. The number of outages caused by animals is increasing, and this can be attributed to the rapid growth of the Grey-headed Flying-fox (bat) colony in SA.
These Flying-foxes, also known as fruit bats, have not always been residents of Adelaide. They arrived here around 2010, setting up a colony in the Adelaide Parklands and can often be seen in the city and inner suburban skies throughout the warmer months.
In warmer months, usually between 10pm and 5am, there may be short power outages around the River Torrens Linear Park catchment area related to the growing colony of Grey-headed Flying-foxes (bats) in SA. Outages related to this will vary between 60 seconds and 2 hours, depending on whether we need to inspect our powerlines. We work with scientists to understand bat behaviour, and we install equipment to minimise the frequency and duration of outages related to animal impact.
Of the animal-related power outages, birds are responsible for two-thirds, and the balance are caused by bats, rats, termites, snakes and lizards.
Birds can cause outages in a number of ways including individually and collectively. For example, if a bird tries to land on lines and or on a Stobie pole and contacts separate lines, they will create a short circuit and most likely be electrocuted. Birds can also get caught on equipment such as lightning arrestors (which are a device for protecting equipment from lightning strikes or power surges).
Large flocks of birds (such as corellas) may roost together on lines and when they take off together, they will cause lines to swing and clash. In other cases, they get caught on lines in between powerlines and transformers - this has been the issue in the past at Mannum and other towns.
We monitor outages to look for patterns; where we have repeat incidents involving animals, we can often install targeted solutions to reduce the likelihood of further outages at that location. For example, line spacers are effective in managing impacts of roosting birds. We have a dish-shaped animal guard which reduces the risk of possum and bird impacts on insulators, and we will replace older-style equipment such as rod air gaps (lightning arrestors) with modern insulated lightning arrestors that are less likely to cause outages when contacted by birds and bats.
While these solutions reduce incidents and repeat interruptions at targeted locations, we are seeing an increase in the number of bat-related outages due to the very rapid expansion of the flying fox colony camped in the Parklands between the Adelaide Zoo and Botanic Gardens.
Due to food supply pressure in their normal eastern-state habitats, the bats have grown from a colony of about 3,000 in 2016 to one of about 25,000 today. In 2016, we had 13 power outages due to bats, in 2017 it was 26 and in 2018 we had 40. Many customers who have lived in the area for years, will likely have noticed more power outages in recent years overnight in summer.
These bats are likely to have a growing impact in terms of the number of power outages they cause. They do not have specific flight paths (they go where the nectar and fruit is) and their impact is widespread across our network, making it difficult to undertake targeted defensive action.
The bats, which have a wide wingspan (over one metre), can cause a power outage when they contact between power lines and pole top equipment, including insulators, transformers and switches or when trapped by lightning arrestors.
We have commissioned a study by the University of Adelaide to help us understand more about bat behaviour, and where we might get best value from outage-mitigation efforts, as some solutions can be expensive
Note: while the bats are not aggressive, they potentially carry a serious disease that is transmissible to humans and should not be handled by members of the public.
The welfare of the protected native Grey-headed Flying-foxes, and all other animals is important to us. We have provided funding to Fauna Rescue who rescue injured animals reported by the public. Their 24/7 bat rescue number is 8486 1139.