Market Design

Market Design Summary

The Market Design Summary provides a high-level understanding of the design and operation of the Wholesale Electricity Market (WEM) and the South West Interconnected System (SWIS).

WEM Reform will see significant changes to the WEM Rules, systems, WEM Procedures and processes.  The Market Design Summary reflects the work completed by Energy Policy WA (EPWA), working with AEMO, Western Power and Market Participants, to design and develop changes to the WEM Rules.

These changes were gazetted by the WA Government in “Tranches” of WEM Rules between January 2020 and March 2023, and contain the key framework elements required for the WEM Reform.  The current published version of the Market Design Summary (V2.0 September 2023) includes those elements developed in Tranches up to and including Tranche 6A. 

This summary replaces the previous version published by AEMO in May 2021 and provides an updated description how the WEM will operate post Reform. It describes the various components of the WEM, their purpose and objectives, and how they interact with each other. WEM Market Participants are encouraged to read the Market Design Summary to assist with understanding of their requirements for operating in the new WEM. 

The WEM is currently undergoing additional reform in various areas, meaning that the WEM Rules will be regularly updated to reflect the outcomes of various reform workstreams. Readers should consider the validity of information in this document against the current version of the WEM Rules. If the reader finds information that it believes is inaccurate, misleading or out-of-date, they are encouraged to contact AEMO at

Cookies help us improve your website experience.
By using our website, you agree to our use of cookies.