On 27 July 2011, AEMO submitted a Rule change request entitled ‘New Prudential Standard and Framework in the NEM'.

AEMO submitted this rule change proposal to give effect to the first set of conclusions from its recently concluded Energy Market Prudential Readiness Review. Specifically, the Rule change request proposes to:

• Remove references to the ‘reasonable worst case' within the prudential requirements;
• Replace ‘reasonable worst case' with a new definition for a Prudential Standard, defining it as a 2% probability of incurring a loss or shortfall in the event of participant default;

Modify various aspects of its calculation process, including:

a) use of individual load profiles and seasonal adjustments in calculating participant prudential obligations;
b) removal of the option for a Reduced Maximum Credit Limit;
c) modification of the methodology used to calculate the Maximum Credit Limit and Prudential Margin.

The Commission has published a final determination to make the rule as proposed by the proponent, with some clarifying amendments. The Commission’s reasons are laid out in the final determination paper. The rule as made is published alongside the paper.