On 27 April 2005 the ACCC released its decision regarding EnergyAustralia's revenue cap application for the regulatory period 2004 to 2009.

The ACCC's decision draws on consultancy reports, submissions from interested parties and the analysis of data and information presented to the ACCC in the course of its deliberations. The decision considers regulatory issues such as the opening asset base, the weighted average cost of capital and the treatment of capital and operating expenditure.

On 21 December 2007, the AER decided to revoke and substitute EnergyAustralia's 2004/05 to 2008/09 revenue cap under clauses 6.2.4(d)(1) and (2) of the National Electricity Code (the Code).

The Australian Competition and Consumer Commission set the 2004/05 to 2008/09 revenue cap. EnergyAustralia requested the AER re-open this revenue cap in March 2007 on the grounds that there was a material error in setting its revenue cap.

The AER determined that there was an error in establishing EnergyAustralia’s cost of debt and had the material error not occurred the ACCC would have reached a different conclusion in setting the revenue cap. As such the AER considers it appropriate to revoke and substitute the revenue cap, in accordance with the provisions of the Code.