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Energy Imbalance Market
On Sept. 26, 2019, BPA signed an implementation agreement with the California Independent System Operator and a record of decision in a move toward joining the Western Energy Imbalance Market in 2022.
With the implementation agreement in place, BPA will begin work on Western EIM-specific projects identified in the grid modernization roadmap and develop a detailed project plan with the California ISO to ensure the necessary systems, processes and training are in place before a proposed go-live date in 2022. The agreement also allows  
BPA to start participating in Western EIM entity meetings and other market development opportunities.
BPA’s decision about whether to join the Western EIM is a five-part process. With the signing of the implementation agreement and the ROD, BPA concludes Phase II of the EIM decision process. The final decision on whether to join the EIM will follow a close-out letter to the region in the fall of 2021 and a corresponding public comment period.

During the third phase beginning in October 2019, BPA will engage customers through a series of workshops through the TC-22 and BP-22 proceedings which will include discussion of Phase III policy discussions outlined in the ROD.

Bonneville conducted a public comment period on the Western Energy Imbalance Market Letter to the Region in July 2019. The package put out for comment included a cover letter from the administrator, an in-depth policy proposal document, a report of BPA’s Western EIM cost-benefit analysis and a draft of the implementation agreement. BPA addressed comments on the package in its record of decision

What is an energy imbalance market?

An energy imbalance market is a voluntary market that provides a sub-hourly economic dispatch of participating resources for balancing supply and demand every 5 minutes. This market is security-constrained, meaning transmission and reliability constraints would be honored.

The Western Energy Imbalance Market is operated by the California Independent System Operator. It is important to note that the Western EIM is not a regional transmission operator. BPA is not joining an RTO. BPA would preserve its autonomy and retain authority over transmission planning, day-ahead marketing, and transmission system and balancing authority operations if it were to join the EIM.

Why join the western EIM?

Selling surplus energy and capacity in the western markets is essential to keeping Bonneville’s rates low. BPA must adapt its business model as these markets change. Our analysis shows that joining the Western Energy Imbalance Market is one potential method to achieve this outcome.

Joining the EIM under the right conditions may result in increased value for the flexibility obtained from the federal hydropower system and other Northwest generators. It could also improve congestion management of the transmission grid. There are still many steps and hurdles to clear before any decision is made. BPA is currently determining how and under what conditions it could join the EIM, with a potential implementation date of April 2022.
Benefits accessible through EIM membership:
  • Congestion management functions that are more economically efficient than present curtailment and bilateral redispatch capabilities. 
  • Optimized day-to-day operation of the power system.
  • Transmission expansion investment decisions.



Phase IV - BP-22 & TC-22


June 17 EIM Implementation Workshop


May 19 EIM Implementation Workshop


April 27 EIM Implementation Workshop


March 16 EIM Implementation Workshop

Feb. 2 EIM Implementation Workshop

Oct. 28 EIM Implementation Kickoff

EIM Phase III Final Decision Document

Sept. 29 TC-22, BP-22 and EIM Phase III Workshop

Aug. 25 and 26 TC-22, BP-22 and EIM Phase III Workshops

  • Meeting slide deck - Aug. 25 and Aug. 26
    • EIM tariff update
    • Real power losses on EIM transfers
    • Donation timing for ETSR
    • EIM resource sufficiency update
    • Transmission rates: EIM charge code allocation
    • Power rates: treatment of EIM charge codes  


July 28, 29 and 30 TC-22, BP-22 and EIM Phase III Workshops


June 23 and 24 TC-22, BP-22 and EIM Phase III Workshops


May 19 TC-22, BP-22 and EIM Phase III Workshops


April 28 TC-22, BP-22 and EIM Phase III Workshops


March 17 TC-22, BP-22 and EIM Phase III Workshop


Feb. 25 TC-22, BP-22 and EIM Phase III Workshop


Jan. 28 TC-22, BP-22 and EIM Phase III Workshop


Dec.12 TC-22, BP-22 and EIM Phase III Workshop


Nov. 19 TC-22, BP-22 and EIM Phase III Workshop


Oct. 23 TC-22, BP-22 and EIM Phase III Workshop

​EIM stakeholder meeting - July 8, 2019

​EIM stakeholder meeting - June 12, 2019

Comments received

EIM stakeholder meeting - April 10, 2019

Comments received

EIM stakeholder meeting - March 13, 2019

Comments received

EIM stakeholder meeting - February 20, 2019

EIM stakeholder meeting - January 16, 2019

​EIM stakeholder meeting - December 18, 2018

​EIM stakeholder meeting - November 14, 2018
Comments received
​EIM stakeholder meeting - October 11, 2018

Comments received

NOTE: Attendees should bring their own printed copy of the presentation to the meeting if a hardcopy is desired. Handouts will not be provided.

EIM 101 Workshop - Sept. 13

BPA will present an Energy Imbalance Market 101 Workshop as part of our ongoing EIM Stakeholder Meeting series.

Comments received

​EIM stakeholder meeting - July 24

Comments received