By Robert Mullin

The Western Energy Imbalance Market is poised to expand across Northern California after three municipal utilities and the Western Area Power Administration’s Sierra Nevada (WAPA SN) division jointly announced they intend to join the growing real-time market.

The Balancing Area of Northern California (BANC) and WAPA said Wednesday they will sign an implementation agreement with CAISO that would allow WAPA SN and BANC members Modesto Irrigation District (MID), Redding Electric Utility and Roseville Electric Utility to begin trading in the EIM in April 2021. The decision does not affect any other WAPA regions.

The agreement represents the second phase of BANC’s approach to incorporating its members into the EIM. Sacramento Municipal Utility District (SMUD) entered the market in April. (See SMUD Goes Live in Western EIM.)

“BANC is excited to expand its participation in Phase 2 after becoming the first publicly owned agency to become an EIM entity,” BANC General Manager Jim Shetler said in a statement. “The success of Phase 1 … and the benefits we’ve realized encouraged more of our public power members to participate. We expect the transition will be as smooth for Phase 2 as it was for Phase 1.”

While SMUD represented the first publicly owned utility to join the EIM, WAPA SN would be the first federal power marketing agency to participate. The Bonneville Power Administration, which operates about 15,000 miles of transmission in the Pacific Northwest, has begun a multiyear effort to examine EIM membership. (See Customers Probe BPA on EIM Impact.)

WAPA SN primarily markets wholesale power generated by the U.S. Bureau of Reclamation’s Central Valley Project, which includes the Shasta, Folsom, Trinity and New Melones dams. Its customers include towns, rural electric cooperatives, public utility districts, federal and military agencies, and Native American tribes in Northern and Central California and parts of Nevada.

Together with BANC, the agency is part owner of the California-Oregon Transmission Project, a 340-mile, 500-kV line that links BANC’s balancing authority area to BPA’s territory. The two connect via the Captain Jack substation in Southern Oregon, one of two major transfer points for energy flowing between the Northwest and California.

“Joining the Western EIM will help SN ensure the reliable delivery of our hydropower while adjusting to a changing energy mix. Given our footprint within the BANC balancing authority area, the Western EIM is the best fit for SN,” WAPA SN Regional Manager Sonja Anderson said.

MID provides electricity to more than 122,000 customers and irrigation water to 2,300 agricultural accounts in California’s Central Valley. The utility’s portfolio consists of about 66 MW of hydroelectric resources and 389 MW of gas-fired generation, including three peaking units.

“Joining the EIM will provide MID continued access to the market’s diverse, readily-available power resource mix,” MID General Manager Scott Furgerson said. “Access to this low-cost, growing pool of resources will also further ensure and enhance service reliability to our customers.”

MID estimates it will incur $3.3 million in start-up costs and about $1 million in annual expenses to participate in the EIM, with recovery anticipated within three years.

Redding Electric serves more than 42,000 residential and commercial customers within the city of Redding and owns 83 MW of gas-fired generation. With about 53,000 customers, Roseville Electric obtains most of its power from its own gas-fired generation and WAPA.

BANC members Shasta Lake and Trinity Public Utilities District have not committed to the EIM.