Investigation into the events of 31 October 2005 in the National Electricity Market

Compliance review
Release date: 
12 October 2006
Related provisions: 

4.9.8(a), 4.11.2, 3.1(a), 4.3.1, 4.2.4(a), 4.2.6, 4.2.2(a), 3.8.22, 3.8.1, 3.7A, 3.1.4

Event date: 
31 October 2005


The AER has published its final report on the events of 31 October 2005 when the failure of a major transmission line in New South Wales caused significant disruption to the market.

The AER investigated the response of market participants to the transmission line failure and subsequent events. The investigation did not identify any breach of the National Electricity Rules but identified scope to significantly improve emergency response practices in the NEM.

The AER has acted on these findings by seeking changes in some of NEMMCO's practices and reviewing aspects of the electricity rules dealing with generator ramp rates.


The AER sought an undertaking from NEMMCO to review its procedures for managing market or market systems failures and outage management; regularly reviewing all key constraints; and its obligations with respect to providing information to the market.

The AER will issue a Compliance Bulletin to the market outlining its understanding of the application of non-conformance provisions of clause 3.8.23 of the Rules and the responsibilities of participants to follow dispatch instructions as required by clause 4.9.8 (a) of the Rules. The AER will also develop and submit a rule change proposal related to the use of technical parameters.

Documents (3) Author