This Rule relates to the bidding and rebidding of ramp rates, market ancillary service offers and dispatch inflexibility.

Background

On 21 April 2008 the Commission received a Rule change proposal from the Australian Energy Regulator (AER) relating to the bidding and rebidding of ramp rates, market ancillary service offers, and dispatch inflexibility.

In its proposal, the AER contended that the Rules currently permit generators to rebid technical parameters such as ramp rates, market ancillary service offers, and dispatch inflexibility in such a way as to inhibit NEMMCO’s ability to reduce the output of generators through central dispatch to manage system security.

The AER submited that the Rule change proposal would limit a participant’s ability to rebid technical parameters to pursue commercial objectives when power system security may be compromised.

On 22 May 2008, the Commission published a notice under section 95 of the NEL advising of its intention to commence the Rule change process and initial consultation on this Rule proposal. The Commission invited interested parties to provide submissions on the Rule change proposal by 19 June 2008.

On 28 August 2008, the Commission published a notice under section 107 of the National Electricity Law (NEL), which extended the period for publication of the draft Rule determination for this proposal. The Commission undertook to publish its draft Rule determination by 30 October 2008. The Commission considered it necessary to extend the publication of the draft Rule determination in order to sufficiently analyse and address complex issues necessary to finalise the draft Rule determination and the draft Rule.

On 23 October 2008, the Commission published a notice under section 99 of the National Electricity Law (NEL) advising of the making of the draft Rule determination and draft Rule. The Commission invited interested parties to provide submissions on the draft Rule determination by 5 December 2008.

On 15 January 2009, the Commission published a notice under sections 102 and 103 of the National Electricity Law (NEL) advising of the making of the National Electricity Amendment (Ramp Rates, Market Ancillary Service Offers, and Dispatch Inflexibility) Rule 2009 No.1 and the corresponding Rule determination.

In making this final Rule, the Commission has largely adopted the AER’s proposal with some modifications. The Rule comprises the following core components that would require relevant scheduled and semi-scheduled generators and market participants to:

• provide a ramp rate that is:
• greater than a minimum ramp rate of 3 MW/minute or 3% or registered unit size except where it can be demonstrated to NEMMCO that a lower ramp rate is required for technical or safety reasons; and
• no more than the maximum ramp rate that an item of equipment is capable of achieving in normal circumstances.
• provide market ancillary service parameters for generators that reflect the technical capability of the generator’s plant; and
• declare themselves “inflexible” only when plant technical constraints justify such a declaration.

The final Rule determination provides more detail and sets out the reasons for the Commission’s decision. This Rule commenced on 31 March 2009.