EnergyAustralia also runs the Tallawarra power station at Lake Illawarra in NSW. Photo: EnergyAustralia.
A gas power station in the NSW Southern Tablelands could run for less than a quarter of the year, according to estimates given as part of planning to amend its plans.
The power station is planned for a site about 12 kilometres north-east of Marulan, in an area spanning the Upper Lachlan and Goulburn Mulwaree local government areas.
The project was first raised and assessed in 2007 and 2008, with approval coming in 2009. Several extensions have been made since then.
The most recent extension was granted in late 2024, pushing the lapsing date to October 2026 so EnergyAustralia could apply for modifications to the given approvals, among other actions.
According to EnergyAustralia’s website for the project, submitting a scoping report to the NSW Government is the first stage in the modification process.
Parts of the recently released report have revealed details about what an amended version of the project could look like.
“The modified project will remain as two gas fired power stations and associated common infrastructure but is proposed to have a total generation capacity of up to 1.43 gigawatts (GW) in an open cycle gas turbine (OCGT) configuration in addition to a number of changes to each approval as further described in [the report],” it states.
It is expected the power station would operate during peak electricity demand, as well as times when renewable energy generation is low or during emergencies.
Under current estimates of the electricity market, EnergyAustralia predicts this would be between 10 and 20 per cent of the year.
According to the scoping report, the modified project would use natural gas as its primary fuel, but would seek approval to also use diesel (as a back-up).
It also flags that 120 hours of diesel firing are expected every year, though “market conditions and electricity demand profiles” may increase this.
Diesel generators or on-site batteries would be used to start the power station during an electricity blackout (known as black start capability).
“As such, the modified project enhances grid resilience and reliability by enabling a rapid and controlled restart of the power system following large scale outages,” the report states.
The report also states the power station’s water needs will depend on its capacity factor (which is itself variable).
“The operational water demand for the modified project would be greater than for the approved project [which was estimated at 10.6 megalitres a year] because of the larger turbines proposed, and because the gas turbine air inlet evaporative cooling system is proposed to improve the output and efficiency of the gas turbines, particularly when diesel fuel is being used,” it states.
“Typical operational water demand has been estimated based on a 15 per cent capacity factor … the maximum operational water demand would be up to 140 megalitres per annum.”
The scoping report states it is “likely that one or more” of three given options would be used to supply the power station with water, as well as the approved options. (These options are a new pipeline connecting to the Highland Source Project water pipeline, water from the Wollondilly River and groundwater from new wells.)
“The additional operational water supply options, and related water supply infrastructure that may be required for the modified project, are still being considered,” it says.
“Once determined, this will be assessed in the modification applications as part of the modified project.”
EnergyAustralia is still considering how it will manage water discharge, flagging options such as evaporation, trucking it off-site to nearby treatment plants, or on-site treatment so the water can be reused.
Construction workers are expected to come from outside the area, and will be housed in Marulan and the surrounding areas.
About 400 people would be employed during the construction phase.
“EnergyAustralia are currently seeking expressions of interest (EOI) from parties, including councils, companies and private landowners, in hosting the temporary construction workers’ accommodation facilities.”
The modifications also move the access road (and propose a new one being built through land owned by EnergyAustralia) to the power station.
More information, including the scoping report, can be found on EnergyAustralia’s website for the project.
