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Energy Imbalance Market
BPA has evaluated whether to join the Western Energy Imbalance Market, with a planned go-live date of May 3, 2022. New market opportunities such as the EIM have the potential to both reduce BPA's costs through greater efficiencies and increase revenues by providing a new way to market surplus power. BPA has completed its five-phase decision process with a final decision on the agency's participation issued on Sept. 27, 2021.
BPA began exploring the feasibility and possible benefits of joining the EIM in 2018. This launched Phase I of BPA's decision process. On Sept. 26, 2019, BPA signed an EIM Implementation Agreement with the market operator, the California Independent System Operator. BPA also signed the EIM Policy Record of Decision in a move toward joining the EIM. With the EIM Implementation Agreement in place, BPA began work on EIM-specific projects identified in the Grid Modernization Roadmap and developed a detailed project plan with the CAISO to ensure the necessary systems, processes and training are in place before the proposed go-live date. The EIM Implementation Agreement and EIM Policy ROD concluded Phase II of the decision process.  
Phase III commenced in October 2019 with discussion of policy issues that could involve rate or tariff changes. These discussions were held during the pre-rate and tariff case workshops. BPA issued the EIM Phase III Final Decision Document on Oct. 30, 2020, covering four issues that could be decided outside of the rate and tariff proceedings. This document ended the third phase of the decision process.
The BP-22 Rate Case and TC-22 Terms and Conditions Tariff Proceeding marked Phase IV of the process. These proceedings, which concluded on July 28, 2021, included important rate and tariff decisions that would enable BPA's participation in the EIM.  

BPA made its final decision to join the EIM on Sept. 27, 2021, when it released the Final EIM Close-out Letter. This letter concludes the extensive assessment and public process conducted through all five phases of the EIM decision process. BPA remains committed to working with customers and constituents as it prepares for market participation and after Go Live.  

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 when it joins 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.



Jan. 27, 2022 EIM Implementation Workshop

Nov. 17, 2021 EIM Implementation Workshop


Phase V - Close-out


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