A new study conducted on behalf of the Minnesota Department of Transportation found that the challenges associated with burying high-voltage direct-current transmission lines along the state's existing rights of way, while significant, are not insurmountable.

The study, released April 12 by a coalition focused on next-generation highways, concluded that burying HVDC lines along existing roadways and railways can actually be done cost-effectively when compared to traditional transmission investments.

Moreover, leveraging existing rights of way can help developers avoid local opposition, potentially cutting development timelines by as much as half, according to the study's authors.

"What we're trying to show is the potential value proposition," Morgan Putnam, founder of NGI Consulting and co-author of the study, said in an interview.

New push to leverage rights of way

The study comes as the Biden administration encourages states to explore harnessing existing rights of way to co-locate electric transmission, electric vehicle infrastructure and broadband communications networks.

The Federal Highway Administration in April 2021 released guidance that for the first time gave alternative uses of rights of way the same priority as traditional transportation uses.

"That memo was really significant on the federal side because it tore down some of the real or perceived barriers for the state DOTs," said Laura Rogers, deputy director of public-private philanthropic partnership The Ray, another group that helped produce the study. The study was also supported by the Great Plains Institute, Satterfield Consulting, Tracy Warren and 5 Lakes Energy.

That same month, the U.S. Department of Energy also announced $5 billion in available loan guarantees for innovative transmission projects with a special priority for projects using high-voltage, direct-current technology along existing rights of way.

Various academic studies have estimated the U.S. will need to double or even triple its transmission capacity by midcentury to achieve the Biden administration's goal of decarbonizing the nation's economy by then.

HVDC lines are increasingly seen as crucial to speeding the U.S. clean energy transition, but they often face stiff public opposition.

Avangrid Inc., for example, is challenging the rejection by Maine voters of its $1 billion, 145-mile New England Clean Energy Connect transmission project after residents there passed a ballot referendum to block the overhead project, which has already broken ground in Canada.

In contrast, the $2.5 billion SOO Green HVDC Link — a 350-mile underground transmission line expected to link the PJM Interconnection LLC and Midcontinent ISO wholesale power markets using an existing Canadian Pacific Railway right of way between northern Iowa and the Chicago area — has received far less pushback.

That line likely would have cost around $1 billion if it was sited above ground, but it also would take about five years longer to build, Putnam said.

"The value proposition associated with going five years faster is about a billion dollars, so you almost with that single benefit alone eliminate any cost differences that exist," Putnam said.

From there, additional monetized benefits could include avoiding carbon dioxide emissions sooner, Putnam explained.

Challenges, solutions

The April 12 report outlined several challenges that states such as Minnesota will need to overcome in undergrounding HVDC lines along existing rights of way.

One of the first is operational staff, Rogers noted.

"When we're talking about building a big transmission line, [state transportation officials] would definitely need some operational support," Rogers said. "They would absolutely need some way to be able to fund that additional capacity because it currently does not exist at the level where it would need to be."

Randy Satterfield, another study co-author who spent nearly 20 years at Wisconsin-headquartered American Transmission Co. LLC, also noted that these types of projects will require close coordination with state utility regulators.

"We need to engage them on this cost-benefit analysis because what we're theorizing and proposing is to look at that in a different way," Satterfield said. "Not just lowest costs, but all of the broad benefits associated with a with a transmission project."

Clearing barriers may also require new legislation. Minnesota, for example, is one of many states with laws that prevent the longitudinal siting of transmission lines along existing rights of way.

"Part of that effort is going to be changing the statute, which is no small feat," Rogers said.

However, Rogers added that roughly 10 state DOTs with a strong interest in harnessing their rights of way were waiting on the study's findings to take further action.

To that end, the study's supporters will soon be launching a new coalition comprising state DOTs, electric utilities and other relevant parties.

"States do have their own unique challenges, but at the same time there is a lot of shared overlap and they can learn from each other," Putnam said.

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