By Robert Mullin
The Western Energy Imbalance Market chalked up another future member Wednesday after Tucson Electric Power signed an agreement with CAISO saying it will join the real-time market in April 2022.
The Arizona utility’s move comes just two weeks after Spokane, Wash.-based Avista announced it would be joining up with the EIM at the same time, potentially bringing the market’s participation level to 15 out of 37 balancing authorities in the West. (See Cold Forces NW to Dip More Deeply into EIM as Avista Joins.)
With Arizona Public Service already trading in the market, and Phoenix-based Salt River Project slated to join in April 2021, TEP’s membership will expand the EIM’s reach to include all of Arizona’s major population centers. TEP, a subsidiary of Canada-based Fortis, serves about 417,000 electric customers in the Tucson metropolitan area.
TEP estimates that participation in the EIM will save the utility about $13 million annually.
“The EIM will help TEP save money for customers by expanding our real-time access to renewable power and other low-cost energy resources across the Western grid,” Erik Bakken, vice president of system operations and environmental at TEP, said in a statement.
TEP owns or controls 2,531 MW of generating capacity, including 255 MW of utility-scale solar and 80.4 MW of wind; its service area also contains about 220 MW of commercial and residential rooftop solar. In March, the utility announced it would sharply expand its renewable energy portfolio with the construction of the 247-MW Oso Grande Wind Project in southeastern New Mexico.
The utility operates 2,175 miles of high-voltage transmission, with key links into wind-rich New Mexico and the neighboring balancing area of Public Service Company of New Mexico, whose own plans to join the EIM in April 2021 have been complicated by moves by state regulators. (See PNM’s Bid to Join Western EIM Gets Approved in Part.)
The EIM’s current members are APS, Idaho Power, NV Energy, PacifiCorp, Portland General Electric, Puget Sound Energy, Powerex and the Sacramento Municipal Utility District, which began transacting last month. The Los Angeles Department of Water and Power and Seattle City Light also are scheduled to go live in April 2020.
CAISO last month said the EIM has yielded $650.26 million in benefits for its members since being launched with PacifiCorp as its first member in November 2014.
