Electricity Markets

Turlock Irrigation District signs agreement for EIM participation

California public power utility Turlock Irrigation District (TID) has signed an agreement to participate in the California Independent System Operator’s Western Energy Imbalance Market (EIM).

TID, an irrigation water and electric utility that has served California’s Central Valley for more than 130 years, will begin participation in the real-time energy market in April 2021, CAISO said on May 14.

TID’s Board of Directors in late March unanimously voted to take the actions needed for it to participate in the EIM. According to TID, its participation in the EIM is expected to generate cost savings sufficient to recoup its start-up costs in two to three years and avoid participation in markets that are expected to become less liquid as EIM participation by other utilities increases. Such reduced liquidity would likely lead to increased purchased power and fuel costs absent TID participation in the EIM.

EIM launched in 2014

CAISO launched the EIM in 2014 and the market’s first participant was Oregon-based PacifiCorp. Las Vegas-based NV Energy followed on Dec. 1, 2015, Puget Sound Energy of Bellevue, Washington, and Arizona Public Service of Phoenix, Arizona, on Oct. 1, 2016, Portland General Electric on Nov. 1, 2017, and Idaho Power and Powerex of Vancouver, British Columbia on Apr. 4, 2018. CAISO on April 4 announced that Sacramento Municipal Utility District, part of the Balancing Authority of Northern California, successfully began full participation in the EIM.

Other entities scheduled to begin participation include Seattle City Light, and Arizona’s Salt River Project in 2020; Los Angeles Department of Water and Power, Albuquerque, N.M.-based Public Service Company of New Mexico and NorthWestern Energy of Butte, Montana in 2021; and Avista of Spokane, Washington and Tucson Electric Power in 2022.


Meanwhile, the Southwest Power Pool on April 4 called on interested utilities and other customers to join in the design and implementation of an energy imbalance market in the West.

SPP has been a certified reliability coordinator for more than two decades, operated an energy imbalance market from 2007 to 2014 and launched a day-ahead electricity market in 2014.

In June 2018, SPP said that it planned to offer reliability coordination services in the western U.S., specifically the Western Interconnection, starting in late 2019.