On 24 May 2018 the AEMC made a final rule to improve the transparency and consistency of information AEMO provides to signal whether or not electricity supply is projected to meet demand in the medium-term.

Final rule

The final rule removes the requirement that AEMO consider network constraints when reporting aggregate generation capacity for each region as part of the medium-term projected assessment of system adequacy, or MT PASA. 

Network constraints will continue to be considered in other relevant MT PASA outputs.

The final rule starts on 31 May 2018.

Background

On 21 December 2017 the AEMC receievd a rule change request from AEMO that sought to amend the National Electricity Rules (NER) to remove the requirement that AEMO consider the impact of network constraints when reporting aggregate generation capacity for MT PASA.

The MT PASA assesses the adequacy of expected electricity supply to meet demand across a two-year horizon. This is done through regular assessment of any projected failure to meet the reliability standard.

On 10 May 2018 AEMO implemented a new MT PASA methodology that probabilistically assesses the risk and uncertainties of power system operation by running simulations to reflect the operation of the national electricty market. The MT PASA process now probabilistically determines whether the reliability standard is projected to be met.

Under the current NER, AEMO is required to report on aggregate capacity of generation in a region after allowing for the impact of network constraints as part of the MT PASA. 

This requirement was drafted at a time when the MT PASA methodology was deterministic. However, assessment of the impact of network constraints is incompatible with the probabilistic modelling approach that has now been adopted in the MT PASA.

Consultation

A consultation paper was published on 12 April 2018 to facilitate discussion on the rule change request. Submissions closed on 10 May 2018. Four written submissions to the consultation paper were received and are available below.

Expedited process

As the rule change request was considered non-controversial, the AEMC followed an expedited rule making process. 

Written objections to the expedited process closed on 26 April 2018. No objections were received.