The Bonneville Power Administration’s (BPA) planned departure from the Western Energy Imbalance Market has prompted questions about how the agency will handle the yearlong period before it joins SPP’s Markets+.

The agency plans to exit the EIM by Oct. 1, 2027, and trade in bilateral markets until Oct. 1, 2028, when it expects to join Markets+, BPA staff said during a day-ahead market participation workshop March 12.

BPA staff don’t expect any hiccups related to liquidity or finding trading partners in a bilateral market, saying, “We’re bidding in with reserves that we’re already holding.”

Libby Kirby, BPA’s Markets+ program manager, said most of the agency’s trades are already bilateral.

“We submit non-regulating balancing reserves as the minimum that we put in the market,” Kirby said. “We will no longer do that. We will return to balancing within the [balancing area]. … We still have … the same methodology. We hold the same amount of balancing reserves.”

Still, meeting participants voiced concern.

“An entire year to be out of the EIM just seems like a really long time, considering that you’re already in the EIM now,” Henry Tilghman, a consultant for the Northwest & Intermountain Power Producers Coalition, said during the meeting. “It seems like it’d be just as much work for operations people to manage in the bilateral market as the EIM.”

Elsa Chang, BPA’s EIM program manager, said the agency will commit resources beginning in January 2028 to start training, system configuration testing and the other necessary steps to join Markets+.

The full year is needed for the “time to do training, to do testing,” Chang said. “We would have to go straight into these SPP activities without much prep time.”

Dan Williams, principal adviser for Western markets at The Energy Authority, supported the plan. By setting a firm timeline, BPA is allowing other entities in the region to prepare for bilateral trading liquidity instead of dealing with uncertainty, he argued. He said he hopes the exit from the EIM will prompt discussions on the seams between Markets+ and CAISO’s Extended Day-Ahead Market, which is to launch May 1, 2026. (See BPA Outlines Next Steps in Markets+ Implementation.)

“There’s no reason that by that point in 2027, we can’t have bilateral markets working better with EDAM that will allow BPA to have markets to buy and sell into and maintain market liquidity across the region, even after exiting the EIM,” Williams contended.

But Chris Roden, director of energy resources at Clatskanie People’s Utility District, asked for more transparency on what the EIM exit will mean, saying the transition feels like a “Jesus-takes-the wheel moment.”

“We have a number of subsequent processes that we run based on that market participation,” Roden said. He added that settlements and rates “have become really contingent upon EIM participation.”