EIM Entities and EDAM Design

Switchyard at sunset.


Joint participation in California System Operator’s Enhanced Day Ahead Market design efforts

EIM Entities – Who we are

The EIM Entities represent an informal group of utilities that are existing or pending participants in the California Independent System Operator’s (CAISO) Western Energy Imbalance Market (EIM). The Entities are also potential participants in the CAISO’s Extended Day Ahead Market (EDAM) now being evaluated through an EDAM market design stakeholder process led by the CAISO. Individual members of the EIM Entity group may hold policy positions that differ from other members in the EIM Entity group.

Exploring a voluntary extension of the EIM to a regional EDAM presents an opportunity to build off the EIM’s success and pursue additional economic and environmental benefits for market participants and their customers across the West.

The EIM Entities collectively have not yet made a commitment to move forward with implementing the EDAM. The group intends to work with the CAISO and stakeholders to develop a comprehensive market design proposal that will allow the EIM Entities to evaluate their individual expected benefits and costs associated with EDAM participation. This website is voluntarily hosted by APS and provides information related to the EDAM design that has been produced or prepared by the EIM Entities.

EIM Entities
Arizona Public Service Company
Bonneville Power Administration 
Idaho Power
Los Angeles Department of Water and Power
NorthWestern Energy
NV Energy
Portland General Electric
Public Service Company of New Mexico
Puget Sound Energy
Salt River Project
Tacoma Power
Tucson Electric Power
Turlock Irrigation District
Seattle City and Light

Feasibility Assessment 9-2019

GRC Scoping Paper Comments 1-2020

Issue Paper and Entity Comments 11-2019

Post Workshop 1 Comments 3-4

Presentation-Congestion Rents 2-20

Presentation-Resource Sufficiency Evaluation 2-20

Presentation-Transmission 2-20

Contact information
If you have questions please send them to: eimentitiesedam@aps.com.

Additional information on EDAM design can be found at caiso.com/StakeholderProcesses/Extended-day-ahead-market

Antitrust statement: The EIM Entities listed here will abide by Federal Antitrust Laws and Guidelines in the conduct of all meetings, discussions and document preparation. Any violation of those requirements are strictly prohibited .

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