Major transmission intertie project gets another boost
FOLSOM, Calif. – The California Independent System Operator (ISO) Board of Governors has approved a pair of provisions advancing a major transmission intertie that will deliver Idaho wind energy to California and the Southwest, while opening additional energy resources for Idaho.
The Board voted Friday to accept a revision to its earlier conditional approval of the 500-kilovolt (kV) Southwest Intertie Project-North (SWIP-North) that allows consideration of a U.S. Department of Energy (DOE) grant to help accelerate development of the intertie. In a companion action, the Board also approved Great Basin Transmission, LLC‘s application to become a participating transmission owner in the California ISO.
Each of the actions is key to advancing a long-anticipated effort seen as a linchpin in strengthening Western electric grid connectivity, optimizing resource diversity, and giving California access to Idaho wind energy consistent with the California Public Utility Commission’s integrated resource planning.
The 285-mile intertie project, estimated to cost about $1.23 billion, includes development of a new transmission line from Midpoint, ID to Robinson Summit, NV. It would create an important transmission pathway by linking to a longer 600-mile line already carrying power from Robinson Summit to just south of Las Vegas, where it connects to the ISO system.
The DOE grant – a total of $331 million – will act as a bridge to speed the project’s construction. When the ISO Board conditionally approved participating in the SWIP-North project in December 2023, Idaho Power had begun negotiations with Great Basin Transmission to acquire about 23 percent of the entitlements – approximately half of the northbound capacity – for energy to move north along the interties. Negotiations and regulatory approval were expected to be completed by now, but funding negotiations are ongoing and Idaho Power still needs to seek regulatory approval, which would delay the project’s start.
Meanwhile, the DOE signed an agreement with Great Basin Transmission for the northbound capacity entitlements being negotiated by Idaho Power. The grant will initially fund Idaho Power’s share of the project, and the DOE will later sell the entitlements. For more information on the DOE grant, view the agency’s fact sheet.
Granting approval for Great Basin Transmission to become a participating transmission owner in the ISO is another critical step for the project, enabling an agreement for the transmission developer to give operational control of its southbound capacity and half of its northbound entitlements on SWIP-North lines to the ISO. That agreement will now go to the Federal Energy Regulatory Commission for review.
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The California Independent System Operator (ISO) is a nonprofit public benefit corporation dedicated, with its partners, to continuous improvement and secure operation of a reliable grid operated for the benefit of consumers.
It provides comprehensive grid planning, open and nondiscriminatory access to one of the largest networks of high-voltage transmission power lines in the world and operates a $9 billion competitive electricity market. Recognizing the importance of the global climate challenge, the ISO is at the forefront of integrating renewable power and advanced technologies that will help provide a sustainable energy future efficiently and cleanly.
The Western Energy Imbalance Market (WEIM) is a real-time wholesale energy trading market that enables participants anywhere in the West to buy and sell energy when needed. The Western Energy Markets Governing Body is the governing authority designed by regional stakeholders and has shared authority with the ISO Board of Governors to resolve rules specific to participation in the WEIM.