What is system strength?
System strength is the ability of the electricity system to withstand shocks and remain within stable operating conditions.
Without enough system strength, there is increased risk that when there is a problem on the network it can lead to blackouts. It can also limit how much renewable energy can safely connect and export to the grid.
Traditionally coal, gas and hydro power stations provided system strength as a by-product of producing electricity. As these ageing generators retire and are replaced by renewable energy, NSW needs new infrastructure to provide system strength.
How is the NSW Government supporting system strength?
To help avoid risks of shortfalls in system strength as we transition our energy system to renewables, we are acting to speed up the delivery of critical new network infrastructure.
Transgrid has conducted a long-term study to identify the best mix of technologies to maintain system strength. It found we need a portfolio of existing generators, ‘grid forming inverters’ on new utility scale battery projects, and ten new synchronous condensers.
Transgrid’s study, called the Project Assessment Conclusions Report, also demonstrated additional net market benefits of more than $1 billion if we could accelerate deployment of five synchronous condensers in the next two to three years.
The NSW Government has entered into an agreement to support Transgrid’s acceleration of its procurement of five synchronous condensers, and directed it to deliver them at five of its substation sites across NSW as a Priority Network Infrastructure Project.
Together, these actions enable Transgrid to sign procurement and construction contracts for this critical infrastructure up to 18 months earlier than normal national regulatory approval processes would allow.
Without the NSW Government’s intervention, the synchronous condensers would likely not be delivered until 2030, several years after a system strength gap is forecast to emerge.
What are the benefits of accelerating system strength infrastructure?
Bringing forward the delivery of the synchronous condensers will:
- help avoid blackouts caused by an unstable grid
- reduce fuel costs, by limiting the need to keep gas and coal generators running to support system strength
- allow more renewables to connect to the grid sooner, reducing energy costs for consumers
- help NSW meet our emission reduction targets.
Frequently asked questions
Synchronous condensers are large rotating machines that help stabilise the electricity grid. They provide system strength by supporting voltage control and fault recovery.
Their purpose is to adjust conditions on the electricity grid so it can withstand disturbances such as the sudden loss of a generating unit or transmission line (e.g. due to lightning strikes) without causing other equipment to 'trip' and stop operating.
Transgrid will install synchronous condensers at five of its sites identified in its July 2025 System Strength Project Assessment Conclusions Report: Newcastle, Kemps Creek (in western Sydney), Armidale, Wellington, and Darlington Point.
These sites were identified by Transgrid as critical to meeting future system strength needs and supporting the connection of renewable energy to the grid.
New technologies, such as batteries with grid forming inverters, have significant potential to provide system strength to NSW’s electricity system.
These technologies have not been deployed in a large-scale power system, without support from synchronous machines. Until we have demonstrated these technologies at scale, the Australian Energy Market Operator and Transgrid require synchronous machines to provide a minimum level of system strength so they can continue to operate the power system.
A Priority Network Infrastructure Project is a designation under the Electricity Infrastructure Investment Act 2020 that allows the Minister for Energy to fast-track critical network projects.
Directing a project gives the state more control over how and when a project is delivered, and helps streamline the cost recovery process.