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Energy Imbalance Market

Bonneville has published a letter to the region, including supporting documents, on its proposal to sign an Implementation Agreement with the California Independent System Operator and move forward toward joining the Western Energy Imbalance Market (EIM).

The package includes a cover letter from the Administrator, an in-depth policy proposal document, a report of Bonneville’s EIM benefits analysis, and a draft of the Implementation Agreement.
Bonneville conducted a public comment period on the letter to the region in July. Bonneville will address comments in a Record of Decision scheduled to be published in September.  If Bonneville decides to move forward with signing the Implementation Agreement, it will execute the Agreement concurrent with publication of the Record of Decision.
A stakeholder meeting to address clarifying questions on Bonneville’s proposal was held July 8.

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 (EIM) is operated by the California Independent System Operator (CAISO). 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.

​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