Four more members join California ISO’s Western Energy Imbalance market

Last week, the Balancing Authority of Northern California (BANC) and Western Area Power Administration (WAPA) announced that WAPA’s Sierra Nevada region (SN), along with BANC members from the City of Redding, the City of Roseville and Modesto Irrigation District, began participating in the California Independent System Operator’s Western Energy Imbalance Market (EIM).

This transition occurred a week earlier than the originally scheduled cut-over date of April 1 announced in September 2019. 

The Western EIM is the west’s first real-time energy market. It enables participating utilities to find the lowest cost energy to balance real-time supply and demand by scheduling power deliveries every 15 minutes with five-minute power plant dispatching. Utilities across a larger geographic area can exchange resources more effectively while significantly lowering the cost of delivering power to consumers.

BANC is a joint powers authority whose members, in addition to the utilities aforementioned, include SMUD, the City of Shasta Lake and Trinity Public Utilities District. SMUD, the nation’s sixth-largest municipal utility, became the first BANC member to join the WEIM April 3, 2019.

“We’re excited that our leadership in the Western EIM successfully demonstrated enough success for our partners to join and expand participation,” said BANC General Manager Jim Shetler. “This means greater reliability, lower costs and improved renewable generation for our customers.”

This move affects only WAPA’s SN region in Northern California and Nevada, which operates a sub-balancing authority within BANC. WAPA is a power marketing administration within the Department of Energy responsible for selling and delivering federal hydropower across high-voltage transmission lines to customers in 15 Midwest and Western states. It is organized in five regions and a management center.

“The Western EIM will help SN better manage real-time supply and demand on a more frequent basis, harness market efficiencies, improve cost-effectiveness and mitigate the loss of bilateral trading partners in real-time energy transactions,” said WAPA Interim Administrator and CEO Tracey LeBeau. “Having a sub-BA put us in a unique position to join the Western EIM; our status required innovative coordination and solutions for market economics, generator dispatch and grid reliability. We greatly appreciate the efforts of BANC and CAISO, as well as ongoing engagement from our customers, to help accommodate these novel challenges and ensure our transition was a success.”

Turlock Irrigation District also began participating in the Western EIM last week. Visit the Western EIM’s website for more information.

Learn more about the Energy Imbalance Market below.

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Jennifer Runyon is a Content Director at Clarion Energy, writing, editing and posting content on POWERGRID International and planning conference sessions for DISTRIBUTECH's live and virtual events. She as the conference advisory committee chair for DISTRIBUTECH International. You can reach her at

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