Western Grid Coordination

Map of EIM participants

PacifiCorp and the California Independent System Operator launched the Energy Imbalance Market in November 2014. The EIM uses a sophisticated system to automatically balance demand every five minutes with the lowest cost energy available across the combined grid.

The EIM leverages the growing diversity of renewable resources, flexible backup resources and demand using advanced technology to keep energy supply affordable and reliable. The market is attracting additional participants and has the benefit of increasing benefits for all customers as diversity increases.

Energy Imbalance FAQs and Fact Sheet
PDF Frequently Asked Questions
PDF Fact Sheet

Quarterly EIM Benefits Reports
The benefits report released on January 30, 2018, showed total benefits of $288.44 million since November 2014. See all benefits reports


Information for transmission customers and stakeholders
Information on EIM can be found on PacifiCorp’s Open Access Same-Time Information System (OASIS)


Expanding regional energy partnerships
PacifiCorp and the ISO announced in April 2015 they signed a memorandum of understanding for the energy company to explore becoming a full Participating Transmission Owner in the ISO.

A study released on October 13, 2015, finds coordinating the electric grids operated by PacifiCorp and the California Independent System Operator (ISO) to create a regional power marketplace could reduce energy costs by billions of dollars and help states meet their environmental goals.

Learn more about the study and the benefits »