Black Hills Energy and PowerWatch are to join CAISO’s Western Energy Imbalance Market, extending the market’s geographical reach into South Dakota, the ISO announced.
Black Hills and PowerWatch, formerly known as BHE Montana, are to join the WEIM on May 6, five days after the scheduled launch of CAISO’s Extended Day-Ahead Market with PacifiCorp as the first participant, CAISO announced Feb. 25.
“We are honored to welcome Black Hills Energy and PowerWatch into the WEIM,” CAISO CEO Elliot Mainzer said in a statement. “The continued growth of our markets delivers real economic benefits to market participants and their customers and is a proven strategy for improved reliability and affordability throughout the region.”
Black Hills and PowerWatch are working with CAISO to complete readiness criteria by March. FERC must approve the readiness certification before they can join, according to the release.
With Black Hills joining the fold, the market’s footprint extends into South Dakota as WEIM’s twelfth Western state, CAISO wrote in a news release.
Black Hills serves 1.35 million natural gas and electricity customers in eight states. In January, the utility announced it had completed construction on a 260-mile, $350 million transmission expansion project to interconnect electric systems in Wyoming and South Dakota. (See Black Hills Completes $350M Tx Project.)
In 2024, Black Hills Power and Cheyenne Light announced they would move from SPP’s Western Energy Imbalance Service to CAISO’s WEIM. (See CAISO’s WEIM Plucks Black Hills Utilities from SPP’s WEIS.)
Under the WEIM implementation agreement signed by Black Hills Power and Cheyenne Light, the utilities agreed to register a new balancing authority to facilitate participation in the market by 2026.
The newly energized 260-mile line is part of Cheyenne Light’s FERC tariff and will be within the WEIM when the utility begins participation in May, according to Black Hills.
PowerWatch is a subsidiary of Berkshire Hathaway Energy. It is the second generation-only balancing authority committed to participate in the WEIM, CAISO stated, with Avangrid in the Northwest being the first.
