Puget Sound Energy has become the latest utility to stake a claim in the North Plains Connector, a 420-mile transmission line from central North Dakota to southeast Montana.
PSE signed a nonbinding agreement with Grid United’s North Plains Connector LLC to buy 750 MW of transfer capacity on the 3,000-MW line — a 25% share. Financial terms weren’t disclosed for the deal, announced Dec. 9.
Grid United, a competitive transmission developer, is partnering with Minnesota-based energy company ALLETE to develop the North Plains Connector. The project is billed as the first high-voltage direct-current (HVDC) transmission link among three regional energy systems: MISO, SPP and the Western Interconnection.
ALLETE will pursue up to 35% ownership of the $3.2 billion project and would oversee the line’s operation, under an agreement with Grid United announced in December 2023. The North Plains Connector is expected to start operations in 2032.
In May, Portland General Electric announced a nonbinding agreement with Grid United and ALLETE in which PGE is expected to hold a 20% ownership share of the project.
That was followed by Avista’s announcement in November of a nonbinding agreement for 300 MW of transfer capacity, or a 10% ownership share. Avista Utilities provides natural gas and electric services to customers in eastern Washington, northern Idaho and parts of Oregon.
Grid United will continue to fund the development of the North Plains Connector. PSE and PGE would invest when regulatory approvals and permits are in place. Avista would invest when the project is operational.
Grid Benefits
The North Plains Connector will run between endpoints near Bismarck, N.D., and Colstrip, Mont. The line of up to 525 kV will be open to all sources of electric generation.
The project is seen as a way to reduce transmission congestion while allowing rapid sharing of energy resources across a vast area with diverse weather patterns and in different time zones.
The transmission line “will play an important role in enhancing the reliability and resilience of the Western grid,” Josh Jacobs, PSE’s vice president of clean energy strategy and planning, said in a statement. “It will be a critical link connecting PSE and its customers to new markets that can provide needed resource diversity to aid in the clean energy transition.”
And after it’s built, the transmission line is expected to promote energy production in Montana and North Dakota.
The project got a boost in August with the award of a $700 million Grid Resilience and Innovation Partnerships (GRIP) grant from the U.S. Department of Energy to the Montana Department of Commerce. The project began the National Environmental Policy Act (NEPA) process for federal permitting in October.
Grid United and ALLETE first announced plans for the North Plains Connector in early 2023. (See Transmission Project Would Span Across Interconnection Divide.)
A study by Astrapé Consulting found that the North Plains Connector could unlock 3,550 MW of capacity across MISO, SPP and the Western Interconnection. The capacity benefit represents the amount of additional demand that could be served without degrading reliability standards. (See Study: Significant Benefits for Merchant Tx Line.)
The study modeled the North Plains Connector as two 1,500-MW HVDC lines connecting SPP and MISO to the Western grid. Results were released in June.
Kris Zadlo, Grid United’s president and chief technical officer, said at the time that the study could encourage deeper analysis of the benefits of interregional transmission projects.
“By shedding light on how grid-connecting projects like NPC [North Plains Connector] enhance reliability and reduce the risk of power outages, we can build a better connected, more resilient grid for the future,” Zadlo said in a statement.