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How transmission along railroads and highways could break open clean energy growth

High-voltage lines buried along road and rail rights of way could carry renewable power across the U.S. — if a lot of novel challenges can be overcome.

Jeff St. John
Jeff St. John
7 min read
How transmission along railroads and highways could break open clean energy growth

Trey Ward, CEO of Direct Connect Development, sees U.S. highways and railroads as the country’s future high-voltage clean power corridors, starting with a 350-mile stretch between Mason City, Iowa and Plano, Illinois.

That’s the path his company has secured for the SOO Green HVDC Link (HVDC stands for high-voltage direct current), a $2.5 billion underground transmission project designed to carry 2.1 gigawatts of power from the wind-rich Midwest to serve the interconnected power grid market stretching from Illinois to the mid-Atlantic coast.

No such interregional transmission project has been built for decades, although many have tried over that time. But unlike failed projects including Clean Line Energy, or others like the Grain Belt Express that is still struggling to win siting and permitting battles for its massive overhead power lines, SOO Green will run underground, primarily along the rights of way of railroad company Canadian Pacific Railway.

“SOO Green solves the greatest challenges facing interregional transmission — siting and permitting, and who pays for it,” Ward said. It helps that technological advances have brought underground HVDC power lines into cost parity with overhead lines, making such a merchant transmission project possible. Jingoli Power, Copenhagen Infrastructure Partners and Siemens Energy are financial backers of the project, and SOO Green opened a solicitation for would-be purchasers of its transmission capacity last year.

Image credit: SOO Green HVDC Link

But comparing costs is almost a moot point, he said. The main factors preventing transmission from being built today are cost-sharing disagreements between utilities, state regulators and grid operators that prevent many projects from getting past the proposal phase, as well as legal challenges from state legislatures and regulators, county agencies and private landowners that can stretch on for a decade or more.

Thousands of miles of and more than $100 billion of investment in new transmission will be needed over the next decade to carry the massive amount of new wind and solar power the U.S. must build to reduce carbon emissions and prevent catastrophic global warming. “This is all about speed,” Ward said. “Speed is the key to meeting President Biden’s ambitious climate goals, and our co-location model can go fast.”

A big new idea for big clean energy goals

The Biden administration appears to agree. As part of its $2.2 trillion American Jobs Plan focused on developing $100 billion in new transmission infrastructure, the plan proposes the creation of a Grid Deployment Authority that can more efficiently “leverage existing rights of way along roads and railways.”

Energy Secretary Jennifer Granholm highlighted the importance of burying transmission and fiber-optic communications along transport rights of way during her Senate confirmation hearing, emphasizing the multiuse potential for electricity and broadband communications, another top administration priority.

John Porcari, managing partner of 3P Enterprises and former U.S. Department of Transportation deputy secretary under the Obama administration, told a Senate committee in March that HVDC transmission along highways could also enable megawatt-scale charging stations for cars and trucks that must be rapidly converted to run on clean power to meet aggressive decarbonization targets.

Because SOO Green is designed as a point-to-point line along railroads, it isn’t set up to do that — “they followed the path of least resistance, a private negotiation with a private railroad that owned virtually all the rights of way,” Porcari said in an April interview.

But “while they’re moving forward and showing the nation that HVDC works and the economics work, we need to rethink the public right of way,” he said. “If you overlay the high-voltage corridors that are needed, it correlates really well with the interstates.”

That overlay is shown in this map from Morgan Putnam, who founded NGI Consulting in 2020 to champion this “NextGen Highway” concept.

Image credit: NGI Consulting

The blue lines are interstate highways. The black lines are hypothetical pathways for HVDC lines that could allow U.S. renewable energy penetration to rise to 85 percent by sharing power across regions, while increasing resiliency against weather-driven grid failures, according to the National Renewable Energy Laboratory's Interconnection Seams Study.

“The modeling shows we can get to 90 percent renewables” within the next 10 to 15 years, Putnam said in a March interview. “But the modeling presumes transmission build-out. That’s a big presumption when, over the past decade, we’ve developed zero gigawatts of interregional transmission.”

In that light, HVDC transmission along highways is “something that can unify the country.” NREL’s Interconnection Seams Study found that “economic benefit [could accrue] to all Americans from building a nationwide transmission grid.”

The same concept could be applied to shorter-range, lower-voltage transmission links better suited for being tapped for roadside charging links, Putnam noted. Last week’s opening of the first large-scale electric truck charging site in the country — the Electric Island project of Daimler Trucks North America and Portland General Electric — highlights the scope of the challenge, with 5 megawatts of simultaneous load equating to the demand of 5,000 houses' worth of power.

Aligning the federal, state and utility powers that be

Plenty of barriers stand between this vision and its realization, however. One is the disconnect between federal and state authority over the interstate highway system. Another is a lack of history demonstrating how utilities and grid planners can work with the states that hold authority over those corridors.

The states are the owners of the interstate rights of way,” Porcari said. “They maintain it under federal standards, but they own it.” And the primary concern of state transportation departments is to make sure nothing they do along those interstates compromises safety, burdens the state with unforeseen costs or restricts their future flexibility to expand the capacity of those roadways.

Porcari, who is also the former secretary of Maryland’s Department of Transportation, says this “ownership” model of interstate highway management needs to shift to a “stewardship” model, emphasizing “the best and highest use” of the rights of way they’re responsible for.

“But it’s a lot to ask all 50 states to work out policies and best practices,” he said. “I think it’s incumbent on the federal government to identify best practices, to create pilot programs and do the downfield blocking and tackling as the states do these pilot programs. There’s no substitute for that kind of federal assistance.”

The Federal Highway Administration does have authority today to allow states to experiment on interstates, he said. The Ray, a nonprofit group using a stretch of Georgia’s I-85 to test solar PV in rights of way and more efficient road surface materials on the highway, is an example of that kind of work.

The Biden administration’s proposed Grid Deployment Authority could boost the federal role in setting standards and encouraging cooperation between states and the utilities, grid operators and transmission developers planning projects, Procari said.

“The compensation should be attractive to a state department of transportation, because it helps them cover operating costs,” he said. As for concerns that building these corridors will snarl traffic or create safety hazards, Porcari advocates for an approach based on “do it once and do it right. Open a trench, do HVDC, do fiber — fiber would be very valuable for the state [departments of transportation] for their traffic management systems.”

NGI Consulting’s Putnam agreed that federal action could help states overcome reluctance to take risks in being among the first to allow this kind of highway right-of-way development.

State transportation agencies are “not exactly incentivized to take risk and often [are] penalized when risks don’t work out,” he said. “That’s where we need to have other stakeholders step up.”

He pointed to work underway between NGI, The Ray, the nonprofit Great Plains Institute and the Minnesota Department of Transportation, which in March agreed to join a multi-stakeholder steering committee to the NextGen highway concept “to better understand the implications and opportunities for Minnesota, including potential updates to Minnesota’s utility accommodation plan.”

Maine and New Hampshire have passed state laws to encourage transmission along transport rights of way, according to a 2020 report from the Federal Energy Regulatory Commission, which oversees the country’s interstate grid operators.

Seeking solutions to transmission's growing pains

The novelty of today’s HVDC technology can also cause problems at the grid level, rather than at the right-of-way and land-use levels. The SOO Green project has plans to complete construction by 2024 and begin connecting to the transmission grid of the Midcontinent Independent System Operator (MISO) and mid-Atlantic grid operator PJM.

But while the project was able to secure an interconnection with MISO relatively quickly, it faces a long wait in the backlogged generation interconnection queue at PJM, Direct Connect CEO Ward said. That’s despite the fact that PJM has a separate queue for transmission projects — “even though we’re transmission, we’re been placed in the generation queue.”

PJM has highlighted the novel nature of SOO Green’s HVDC interconnection, which operates much differently than a traditional alternating current (AC) transmission line, contending that its uniqueness demands a more thorough examination of its impact on the grid. Merchant transmission projects are also different from the transmission needs identified by grid operator plans and paid for via cost-allocation processes.

But Ward says the decision could throw off SOO Green’s planned 2024 completion date. PJM had 145 gigawatts of generation projects in its queue, of which 92 percent were wind, solar and battery storage projects, Manu Asthana, CEO of the grid operator, said in a February presentation.

Ironically, one of the main barriers to getting many clean energy projects interconnected has been the lack of transmission capacity to support them — a constraint that’s now holding back a transmission project that itself could help ease backlogged wind power projects in MISO, Ward pointed out.

Direct Connect hopes to find a way to speed this process with PJM, he said. The company has also discussed the issue with FERC chair Richard Glick, who has cited transmission policy reform as a key goal for the agency this year.

The company is also awaiting more details on how Biden’s transmission policy program could speed the development of more projects like SOO Green, Ward said.

We’re very excited about the Grid Development Authority and that President Biden wants to unleash private capital to expand transmission,” he said. “The goal is that he wants to go fast. We’ve built a better transmission mousetrap with SOO Green that allows us to go fast.”

(Article image credit: Kimi Lee)

transmission gridhighwaysrailroadsSOO Green HVDCClean LinePJMMISOgrid operatorBiden administrationutilitiesclean energy

Jeff St. John

Jeff St. John covers technology, economic and regulatory issues influencing the global transition to low-carbon energy. He is former managing editor and senior grid edge editor of Greentech Media.