Supplementary reserve capacity will be procured by AEMO if, at any time after the day that is six months before the start of a capacity year, it determines that insufficient capacity is available to satisfy demand.

AEMO may call for tenders or negotiate directly with potential suppliers of supplementary reserve capacity. This can be provided by load reduction (where the load is not already associated with a demand side programme) or generation services that are not registered facilities or do not hold capacity credits for the relevant reserve capacity cycle.

In accordance with clause 4.24 of the Wholesale Electricity Market (WEM) Rules, the required supplementary reserve capacity of 120 MW was procured through contracts for the 2008-09 summer period. However, no supplementary reserve capacity has been dispatched in the WEM to date.