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Re-energizing U.S. Transmission Infrastructure

Updated: Feb 22, 2023

Dr. James McCalley champions developing a macrogrid to transmit renewable energy nationwide and add resilience and reliability to the national power grid.

When Jim McCalley was applying to college at Georgia Tech in 1977, he knew he wanted to study engineering, but wasn’t sure which discipline to choose for his major.

“I chose electrical engineering because I thought it was the most difficult. And I thought for sure I would fail,” he recalls. “But if I started with the most difficult one, and failed, then I could move to the next most difficult one, and continue doing that until I succeeded.”

Dr. James McCalley, Distinguished Professor of Engineering, Iowa State University - Photo courtesy of Iowa State University
Creating Balance

Today, McCalley, an Anson Marston Distinguished Professor of Engineering and the Jack London Chair in Power Systems Engineering at Iowa State University (ISU), has not failed.

Backed up by advanced degrees in electrical engineering and power systems engineering, in fact, he’s become an expert in identifying and helping design cost-effective ways to balance the power demand and generation requirements of the national electric grid. Along the way, he’s also become a leading voice––indeed a national authority––on an emerging transmission concept called the macrogrid, a framework McCalley believes is foundational to achieving President Biden’s national goal of producing 100 percent clean electricity by 2035.

Delivering Power to the People

He describes the proposed macrogrid as a “high-capacity, multi-regional transmission overlay” of the existing alternating current (AC) system.

A concept for the macrogrid. Artwork courtesy of J. McCalley and Q. Zhang, Iowa State University

In fact, it would be a national network of multi-regional, high-capacity, high-voltage direct current (HVDC) transmission lines connecting the major sub-grids or interconnections that make up the national electric power grid today. HVDC lines would connect to existing or updated alternating current (AC) networks that distribute electricity within regions.

Some observers have likened the macrogrid to a Federal Interstate Highway System for electricity.

“If we’re going to decarbonize the national electric grid, we’ll have to rely largely on renewable wind, solar and hydroelectric energy,” McCalley observes. “To achieve that goal, we’re going to need massive investments in transmission to move renewable energy efficiently from where it’s produced – in the Midwest (wind), Southwest (solar), and Northwest (hydro) – to where it’s needed in major population centers.”

Developing a macrogrid, he contends, would also add reliability and resilience to the national power grid; provide the ability to respond quickly to regional power crises such as the cold-weather-induced outages experienced by Texas in Feb 2021; and create the ability to share power-generation capacity easily among regions.

Discovering Engineering

McCalley grew up in northeastern Atlanta, the son of a dad trained in civil engineering––“he liked to make things, build things, fix things,” McCalley recalls––and a mom who parlayed an undergraduate degree in journalism into a master’s degree in education and a career teaching English.

McCalley grew up in northeastern Atlanta. Photo by davidkosmos /Creative Commons BY-NC-ND 2.0

In high school, McCalley got his first look at engineering when an 11th-grade physics teacher, Mrs. Sanders, encouraged him to take her class. He liked it so much, in fact, that he took another Sanders’ physics class in 12th grade, motivating him to choose engineering as his college major.

When he shared that decision with his parents, McCalley remembers, “they told me I could attend any engineering school I wanted – as long as it was in Georgia.”

At the time, Georgia Tech was the only school on that list.

As an undergraduate, McCalley split his time between studying power systems engineering on campus and working alternate quarters as a cooperative student at the Atlanta Gas Light Company, a natural gas wholesaler.

Falling in Love … with Transmission

After completing his bachelor’s degree in 1982, McCalley spent two years teaching high school in Sierra Leone as a member of the Peace Corps, then returned to Georgia Tech in 1984 to earn his master’s degree. His next stop was San Francisco, where he “fell in love” with transmission systems while working as a transmission planning engineer for Pacific Gas & Electric.

U.S. transmission infrastructure largely comprises above-ground transmission towers
A macrogrid would redefine transmission infrastructure in the U.S. -- Brooks McKinney photo

“I wasn’t really thinking about macrogrids then,” he recalls, “but I did a lot of design studies and analysis related to developing two closely related transmission corridors, the Pacific DC Intertie and the Pacific AC Intertie, which deliver electricity from Oregon to Southern California.

After completing his PhD in power systems engineering at Georgia Tech in 1992, McCalley took a faculty job with ISU.

And he’s been there ever since.

Starting with Reality

According to the U.S. Department of Energy (DoE), the nation’s electric power grid comprises three major sub-grids: the Western Interconnection, the Eastern Interconnection, and the Texas interconnection (overseen by the Electric Reliability Council of Texas).

These grids are large – the eastern grid has a generating capacity of 700,000 Megawatts (MW) while the western grid has 250,000 MW––but there’s only 1,460 MW of transmission capacity across the “Seam” between the two regions. This rather minuscule cross-seam flow––it has been likened to a garden hose connecting two very large swimming pools––is handled by eight HVDC back-to-back transmission facilities.

Offshore wind energy could be a critical part of helping the U.S. achieve a green electric grid. -- Ørsted photo

A macrogrid, McCalley contends, could significantly increase transmission capacity between the Eastern and Western Interconnections while also delivering renewable energy to major population centers across the country. Ideally, he adds, the macrogrid would also connect to offshore wind farms near the Eastern Seaboard.

“The more comprehensive the macrogrid is in delivering renewable energy to load centers," he says, "the more effective it will be in helping the nation meet its grid decarbonization goals."

Acknowledging Challenges

Not surprisingly, not everyone is ready to embrace the macrogrid. For one thing, there’s the potential development cost of some $50 billion.

There's also a recurring jobs issue. Some states, McCalley notes, would rather develop their own renewable energy generation jobs than import “out-of-state” energy using a macrogrid – even if that imported energy would be less expensive than the “home-grown” variety.

Silhouette of two transmission line workers
Some states may prefer to develop their own energy generation jobs instead of relying on a macrogrid. Photo by Gunshe Ramchandani/Pexels

“Transmission is not a huge job creator in terms of infrastructure, but energy generation is,” he says.

Watching the Future Grow

In spite of such opposition, McCalley is encouraged by pockets of progress toward a future that could include macrogrid.

“The transmission project for which I have seen the least resistance has been the SOO Green HVDC Link project, which plans to deliver wind power from Iowa to the Chicago area, all underground,” he says. “They are burying their transmission lines along railroad rights of way.”

Burying transmission lines is usually more expensive than constructing overhead lines, McCalley admits, but it also eliminates consumer resistance to the visual, land, and environmental impact of above-ground transmission lines.

Focusing on Routine

Workdays for McCalley begin early in the one-story ranch house in Ames, Iowa that he shares with his wife, a golden doodle named Millie, and a guinea pig named Pippin. After walking the dog, showering and preparing a light breakfast––he prefers non-fat milk and granola––McCalley, a Christian, devotes 15 to 30 minutes each morning to reading the Scriptures.

Iowa State University in the fall. Photo courtesy of Christopher Gannon/Iowa State University

Then it’s off to his office on the ISU campus, typically a five-minute (or less) drive in his Chrysler Pacifica hybrid.

“I definitely prefer to work in my office,” he says, COVID-19 notwithstanding. “The stuff around me helps create the mood I need to focus on my research.”

Speaking Transmission

As a tenured professor, McCalley splits his time primarily between teaching and research. When he’s not contemplating the best ways to create a macrogrid, he teaches undergraduate and graduate classes in power systems engineering, and guides a Ph.D. curriculum in Wind Energy Science, Engineering and Policy, all in person again starting in 2022.

And as much as he enjoys his regular interactions with students, McCalley admits to being somewhat of a nerd.

“I always like to say I was raised in industry,” he says, recalling his 10 years of work with Atlanta Gas Light and PG&E. “I really enjoy interacting with industry engineers because I understand their language.”

Making Room for the Macrogrid

Looking ahead, McCalley is measured in how he thinks about the macrogrid, but

hopeful that support for it will grow.

“Climate change is definitely motivating renewables, and renewables are motivating interest in the macrogrid,” he observes. “But once that discussion gets off the ground, the additional benefits of grid reliability, resilience and adaptability become very apparent. If we can make the macrogrid a national bipartisan issue, I think we’ll have a strong chance of success.”

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