EIM Map, Sept. 2019

Active and pending participants in CAISO's EIM.

The existing Western Energy Imbalance Market is set to grow with the announcement that a couple of new members intend to join in April 2021, but a proposal for a similar regional balancing market by the Southwest Power Pool is also drawing interest.

On Sept. 4, the Balancing Authority of Northern California and the Sacramento Municipal Utility District said they have begun a "Phase 2" integration into the existing EIM, which has been operated by the California Independent System Operator since 2014.

The Phase 2 process would bring Modesto Irrigation District and the Western Area Power Administration's Sierra Nevada region into CAISO's EIM, according to a news release. Pending approval by local governments, the cities of Redding and Roseville would also join.

"BANC is excited to expand its participation in Phase 2 after becoming the first publicly owned agency to become an EIM entity in the Western EIM," BANC General Manager Jim Shetler said in a news release. "The success of Phase 1 BANC/SMUD 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."

In Phase 1, BANC member SMUD began participating in the EIM in April. BANC is a joint-powers authority whose members also include the City of Shasta Lake and Trinity Public Utilities District. 

The BANC Commission on Aug. 21 voted to proceed with Phase 2 and execute an EIM implementation agreement, the release says. The decision affects WAPA's Sierra Nevada region, which includes parts of California and Nevada. Other WAPA regions are also exploring an energy imbalance market, which provides wider regional opportunities to sell and balance power.

"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 Senior Vice President and SN Regional Manager Sonja Anderson said in the release.

Meanwhile, a mix of Colorado investor- and publicly owned utilities including Xcel Energy, Black Hills Energy, Platte River Power Authority and Colorado Springs Utilities said they have launched a study into joining an EIM—either CAISO's or a separate and more recently proposed market by the Southwest Power Pool.

The four utilities said they have hired The Brattle Group to evaluate joining an EIM. CAISO's EIM is being considered, as is a new Western Energy Imbalance Service Market proposed by SPP in April. Little Rock, Arkansas-based SPP oversees an electric grid and wholesale power market in the central United States for utilities and transmission companies in 14 states.

The four Colorado utilities currently share resources and help each other balance demand at peak periods through a joint dispatch agreement, but they see value in possibly joining a wider market to help integrate renewable energy, the release says. They also cited passage of legislation that directed the Colorado Public Utilities Commission to investigate the potential costs and benefits of energy markets.

"Working together, we have the potential to drive down fuel costs and provide customers with more energy from wind and solar resources," Xcel Energy Colorado President Alice Jackson said. "We're pleased to continue this regional collaboration and urge other power providers to consider joining us to benefit both customers and the environment."

"We are committed to offering our customers clean, more diverse and affordable energy," Colorado Springs Utilities CEO Aram Benyamin said. "This regional partnership provides us the opportunity to integrate more renewable energy into our system at a lower cost."

The results of the Brattle Group study are expected by the end of the month and a decision by the end of the year.