WEIM participants realize $436 million in first quarter benefits

Contact: ISOMedia@caiso.com

Energy transfers show the value of cooperation during an extreme winter event

FOLSOM, Calif. – The Western Energy Imbalance Market’s (WEIM) cumulative benefits rose to $5.49 billion during the first three months of this year, while also demonstrating the value of regional coordination by helping maintain system reliability during a January cold snap that stressed grid conditions in the Northwest. 

During the first quarter of 2024, the WEIM’s 22 participants realized $436 million in benefits that reduce expenses for those utilities and their customers. The efficient transfer of power across a broad and diverse footprint helped meet demand in the Pacific Northwest during extreme cold January 13-15. Energy transfers from California and the Southwest provided valuable assistance to those areas that were strained due to heightened demand for electricity. 

The WEIM, a real-time electricity market launched in 2014, enables participating entities to buy and sell power close to the time electricity is generated and consumed. Using state-of-the art technology, the market finds and delivers lowest-cost resources to meet immediate power needs and manages congestion on transmission lines to maintain grid reliability. 

The 2024 Q1 economic benefits by participant are as follows: 

(millions $) 

Arizona Public Service$5.54
AVANGRID Renewables$10.14
Balancing Authority of Northern California$20.78
Bonneville Power Authority$18.11
California ISO$54.33
El Paso Electric$6.08
Idaho Power$11.30
Los Angeles Department of Water & Power$46.80
NV Energy$32.77
NorthWestern Energy$7.07
Portland General Electric$22.00
Public Service Company of New Mexico$7.30
Puget Sound Energy$25.88
Seattle City Light$5.76
Salt River Project$22.35
Tacoma Power$6.79
Tucson Electric Power$9.11
Turlock Irrigation District$1.22
WAPA Desert Southwest$16.52

Building on the proven success of the WEIM, the ISO has collaborated with Western stakeholders to develop an Extended Day-Ahead Market (EDAM) that enables entities participating in the WEIM to benefit from optimized and efficient commitments in the day-ahead market to meet next-day demand, where the majority of energy transactions occur. For more information, please view the EDAM fact sheet

For more information visit the WEIM website.

# # #


California ISO | 250 Outcropping Way | Folsom, CA 95630 | www.caiso.com

The California Independent System Operator (ISO) is a nonprofit public benefit corporation dedicated, with its partners, to continuous improvement and secure operation of a reliable grid operated for the benefit of consumers. It provides comprehensive grid planning, open and nondiscriminatory access to one of the largest networks of high-voltage transmission power lines in the world, and operates a $9 billion competitive electricity market. Recognizing the importance of the global climate challenge, the ISO is at the forefront of integrating renew able power and advanced technologies that will help provide a sustainable energy future efficiently and cleanly.  

The Western Energy Imbalance Market (WEIM) is a real-time wholesale energy trading market that enables participants anywhere in the West to buy and sell energy when needed. The WEIM Governing Body is the governing authority designed by regional stakeholders and has shared authority with the ISO Board of Governors to resolve rules specific to participation in the WEIM.

Back to top