Since 1 October 2023, the Wholesale Electricity Market (WEM) has operated under new rules where energy and five frequency co-optimised essential system services are co-optimised and dispatched in five-minute intervals.
Offers in the WEM are capped at the Energy Offer Price Ceiling to mitigate the exercise of market power.
Under the transitional provisions for the commencement of the new market, the alternative maximum STEM price for September 2023 ($738/MWh) was applied as the Energy Offer Price Ceiling from 1 October 2023.
On 17 December 2024, the ERA published its Final Determination, determining the new Energy Offer Price Ceiling to be $1000/MWh.
The new Energy Offer Price Ceiling is effective from 1 January 2025, and subject to review within 3 years.