Not too hot, not too cold – find out how gas storage is used to keep the southern states warm during winter.

As the weather starts to cool down, it’s no surprise that many Australians will flock to their gas heaters to warm up their families and homes.

But with increased heating comes increased gas use, and as the Australian Energy Market Operator, it’s part of our role to make sure that there is enough gas available in the system to continually meet your needs.

But with so many gas consumption regions constantly changing their gas requirements, I’m sure you’re wondering how we manage to keep up with the winter gas demand of Australia’s cooler southern states. The answer? Gas storage.

Located on top of a depleted gas reservoir in south-west Victoria, the Iona underground gas storage facility (owned by Lochard Energy) is Australia’s largest independent east-coast gas storage facility.

The gas storage plant can store up to 23.5 petajoules of gas, and works by pumping excess supply 1.2 kilometres underground, which can then be extracted for later use.

“Storage facilities built using depleted gas fields is globally one of the most common and cost-effective ways of storing natural gas, as it takes advantage of the existing gas and pipeline infrastructure,” said Matthew Clemow, Group Manager, Gas Real-Time Operations.

“These storage facilities are used by gas retailers (like AGL, Origin, and EnergyAustralia) to supply customers when demand is high. During low gas demand periods during summer, gas is withdrawn from the gas pipeline network and large compressors are used to pump it underground into the gas storage reservoir. The reservoir, which is a depleted gas field, is a deposit of porous rock covered by a cap of hard rock. It is not a cave or a cavern. Gas is then withdrawn from the reservoir when needed,” said Matthew.

A graph of the average daily Victorian gas demand in comparison with peak demand days

With the average Victorian winter’s day using approximately one petajoule (or 1,000 terajoules, 1,000,000 gigajoules or one billion megajoules (MJ on your gas bill) of gas, the Iona gas storage facility is used to top up other sources of gas supply to meet demand, as well as supply additional gas in the case of an unplanned gas production plant outage.

On average, Victorian households use 63 gigajoules of gas a year. Which means it would take more than 15 thousand years to make your way through one petajoule! In New South Wales, the average gas use is even less with households using only 26 gigajoules a year.

“Given the enormous size and length of Australia’s gas pipeline system, which is used to transport gas from Queensland to help supply winter demand in the southern states, the Iona facility is important for meeting short term changes in demand as it is only 200 km from Melbourne,” said Matthew.   

As the gas and electricity markets continue to converge, the Iona gas storage facility is also able to help supply gas fired power stations located across the southern states with the fuel that they need to generate electricity.

“During the summer months, AEMO still manages peak gas demand days, however, this time it’s for electricity,” said Matthew.

“Having the Iona storage facility and other sources of flexible gas supply, means that we have an additional reserve fuel source that can supply the power stations on high demand days or when generation from other sources is low,” he said.

Victoria uses the most gas for domestic heating while South Australia uses a large amount for power generation.

With gas playing such a large role in both our energy markets, the management and storage of this resource is something AEMO takes seriously.

So next time you flick on your stove, heater or hot-water system, have a think about the long journey this gas might have taken to travel to your doorstep.

For more information on gas in Australia’s east-coast, check out this link as well - http://energylive.aemo.com.au/News/Sector-changes-deliver-improved-gas-supply-outlook