The AEMC has made a draft rule requiring electricity generators to respond automatically to changes in power system frequency to help keep the system secure. 

Stable frequency is an important part of maintaining a secure power system. Frequency varies whenever electricity supply does not exactly match consumer demand and uncontrolled changes in frequency can cause blackouts.

Today’s draft rule proposes introducing a mandatory obligation for all registered generators in the national electricity market to provide primary frequency response outside of a narrow band either side of 50Hz to help control power system frequency. 

Under the draft rule, AEMO would develop and publish primary frequency response requirements that set out the performance parameters which generators must meet. Generators could ask AEMO for an exemption or variation of the performance parameters if they face excessive compliance costs or do not have the ability to provide automatic frequency response, for example older wind turbines or specialised combined cycle gas turbines. 

The draft rule is designed to address an immediate need for improved frequency control which has been identified by AEMO. It would be an interim measure that would be in place for three years. 

In the meantime, the AEMC will work with AEMO, the Australian Energy Regulator and the Energy Security Board to develop payment mechanisms to incentivise industry to provide frequency response services. The mechanisms will encourage investment and innovation by rewarding businesses such as utility-scale batteries that can provide fast frequency response. This work is being progressed through the AEMC’s frequency control work plan and AEMO’s Removal of disincentives to primary frequency response rule change request. 

AEMC Acting Chief Executive Suzanne Falvi said an increase in the provision of primary frequency response from generators would improve the security of the national electricity system.

“This draft rule gives AEMO greater confidence that it is maintaining the power system in a secure operating state,” said Ms Falvi.

AEMO Chief Executive Officer and Managing Director Audrey Zibelman said: “The changing nature of the power system under-pinning the NEM has resulted in a lack of effective frequency control, which poses risks to system security. This rule change calls upon capable generation plant, both existing and new, to automatically respond to frequency changes and ensure that power system frequency is adequately controlled. It is a critical step towards improving system resilience and predictability.”

Submissions on the draft determination are due by 13 February 2020.

Media: Kellie Bisset, Media and Content Manager, 0438 490 041; (02) 8296 7813


In recent years, the control of frequency in the power system has been deteriorating. This deterioration is mainly due to the detuning of the frequency responsiveness from existing synchronous generating plant. At the same time the increased connection of variable generating technologies makes the task of managing power system frequency following system disturbances more challenging.  

The final report of the AEMC’s Frequency control frameworks review highlighted several issues with the existing market and regulatory arrangements for frequency control. It included a collaborative frequency control work plan – now underway – that sets out a series of actions to be progressed by the AEMC, AEMO and the AER to address issues related to frequency control in the national electricity market over the short and long term.