A heavy construction crane lifts a segment of a transmission tower into place along a rural expressway.
Workers erect a transmission tower in Minnesota. Credit: Xcel Energy

The Midwest’s regional transmission grid operator this week announced another multi-billion dollar phase of transmission line projects as part of a four-part push to improve reliability and reduce curtailments.

The Midcontinent Independent System Operator (MISO) unveiled plans Monday for what’s known as its “Tranche 2” portfolio, which includes plans for several 765 kilovolt transmission “highways” spanning sections of Minnesota, Iowa, Wisconsin, Illinois, Indiana, Michigan, North Dakota and Missouri.

Many of the new lines would connect to projects being built as part of the $10.4 billion Tranche 1 portfolio, which MISO approved last year. Tranche 2 is projected to cost even more, at between $17 billion and $23 billion. A third batch of projects will focus on the grid operator’s southern territory, and the fourth will address north-south connections.

In its presentation to stakeholders, MISO officials said the investment will help manage challenges in three regions. In MISO West, which includes Minnesota, Iowa, North Dakota, Wisconsin and Michigan’s Upper Peninsula, 20% of its facilities are overloaded and annual curtailments exceed 15%.

In its Central region, composed of parts of Illinois, Indiana, and Missouri, facilities are 10% overloaded, and there’s a need for transmission to move power from west to east.

MISO’s East Region, defined as Michigan’s lower peninsula, suffers annual curtailment of over 15% and 10% of facilities are overloaded. MISO said in a presentation that transmission would help mitigate “import and export power swings between day and night.”

Beth Soholt, executive director of the nonprofit Clean Grid Alliance, said the Tranche 2 plan is  “bold” and “the direction we need to go.” The question is: does it go far enough?

The regional grid is expected to see significant growth from industries, electrification, data centers and other sources, Soholt said. 

“If load growth ramps up faster than the grid can handle, then we’re behind the eight ball again,” she said. “Now is the time to ask: Have we right-sized this portfolio?”

Mike Schowalter, senior manager of wholesale electric grid transition for Fresh Energy, said he was surprised by the lack of a High Voltage Direct Current (HVDC) line.

“If we’re looking at the long-term, we’re going to need the attributes that HVDC brings,” Schowalter said.

The Energy News Network is an independent journalism program of Fresh Energy.

A 765 kV transmission line needs taller towers and a much wider corridor than HVDC or other alternatives, Schowalter said. 

“I’m a little concerned about some of the siting issues that the different states will have to deal with,” he said, noting that the map shows a 765 kV Minnesota River crossing.

Utilities have told Schowalter that the plan misses future pockets of generation that may need additional transmission. He said the reason may be because the draft report centers on reliability, not interconnection constraints.

The plan also does not venture much into North Dakota, which has plenty of wind generation, Schowalter said. The draft plan “will help with some congestion, but will it help enough?” he said. “Probably not. In terms of relative to what we need, we need a lot more than this.”

Some utilities also think deploying HVDC lines would better solve grid instability issues, especially between wind-rich Southwest Minnesota and the more populated regions to the east, Soholt said. HVDC transmits electricity more efficiently than alternate current lines, which have higher rates of power loss. 

Utilities have often had to curtail wind power from southwest Minnesota because of transmission capacity issues. Clean energy advocates and others will be closely listening to the business case MISO will make later for the choice of the transmission locations and the size of the lines, she said.

Soholt said comments are being taken now on the plan and some stakeholders will offer modifications and alternatives. Some clean energy developers and members of the Clean Grid Alliance plan to suggest alternatives. Some organizations are expected to argue that MISO does not need this much transmission and others will tender a different vision, she said.

So far, MISO has released only a rough map of where the lines would run, without much detail. A stakeholder process will refine precisely where the lines will operate, Soholt said. 

Stakeholder input and alternatives to the Tranche 2 plan will be accepted through April 5. MISO will make a final decision later this year.

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Frank is an independent journalist and consultant based in St. Paul and a longtime contributor to Midwest Energy News. His articles have appeared in more than 50 publications, including Minnesota Monthly, Wired, the Los Angeles Times, the Minneapolis Star Tribune, Minnesota Technology, Finance & Commerce and others. Frank has also been a Humphrey policy fellow at the University of Minnesota, a Fulbright journalism teacher in Pakistan and Albania, and a program director of the World Press Institute at Macalester College. Frank covers the state of Minnesota.