Power System Security and System Strength

System security and the network operability of the power system underpin the reliability of the transmission network and the balance of supply (generation) and demand (load) required to meet customer needs. Power system security needs are technically complex, at times may be challenging to address, and are critical to the ongoing stability of the transmission network, particularly as the mix of generation changes during the energy transition.

Roles and responsibilities

The Australian Energy Market Operator (AEMO) and Powerlink are responsible for the planning and delivery of power system security services in Queensland. 

AEMO’s annual Transition Plan for System Security considers the need for services across all regions of the National Electricity Market (NEM), and evaluates requirements for system strength, inertia and Network Support and Control Ancillary Services (NSCAS). Powerlink makes system security services available to AEMO, using network or non-network solutions, or a combination of both.

To ensure we deliver cost-effective system security solutions, Powerlink consults with NEM participants and other interested parties as part of the procurement process. If the solution is needed within 18 months of being identified by AEMO, Powerlink may issue an Expression of Interest (EOI) for non-network solutions. Where the service is needed greater than 18 months away, Powerlink will undertake a Regulatory Investment for Transmission (RIT-T) to assess the feasibility of network and non-network solutions.

System Strength

Under the National Electricity Rules, Powerlink is required to meet the two components of Queensland’s system strength as set by AEMO forecasts.  

These components consist of the minimum level of system strength required for power system security, and the additional level of the service required for a stable voltage waveform to host projected levels of inverter-based renewables.

System strength is a measure of the ability of the network to control the voltage both during steady state operation and in response to a network disturbance, such as a sudden change in generation or load, or fault on the network.

Failure to maintain system strength could result in power outages in Queensland.

A range of technologies can deliver replacement system strength services. These include synchronous condensers, grid-scale battery energy storage systems (BESS), gas turbines and pumped hydro energy storage (PHES).

In June 2025, Powerlink completed a RIT-T to address system strength requirements in Queensland from December 2025. Learn more about this consultation.