North Carolina eyes grid-enhancing tech to improve aging power lines

Last summer, utility Duke Energy joined U.S. and state officials to announce with fanfare that it would rebuild a 40-mile transmission line between hurricane-prone Goldsboro and Raleigh, North Carolina. The company said the new infrastructure would result in fewer power outages, more solar connected to the grid, and hundreds of new jobs.

Funded jointly by the federal government and Duke, the project highlighted how advanced technology can help solve the problems posed by an aging electric grid: It will include cables better able to withstand extreme weather and modern support structures that can accommodate new sources of power.

“The grant announced today by the Department of Energy is a win for the communities Duke Energy serves, and signals North Carolina’s leadership in the energy transition,” Kendal Bowman, president of the utility’s North Carolina operations, said at the time.

But advocates and experts say the Lee-Milburnie transmission line in Eastern North Carolina is just the tip of the iceberg. To save consumers money and meet growing energy demand, they believe policymakers should follow other states’ lead and encourage Duke to perform many more grid upgrades like the one unveiled last summer.

Bipartisan legislation that would do just that failed to meet a key deadline last week, but its contents could still end up in another bill before the session ends later this year. Backers of the measure remain hopeful, in part because it would benefit all energy sources, not just renewable ones.

“It’s not a clean energy bill,” said Mel Mackin, state policy director for the nonprofit advocacy group Ceres. ​“It’s a grid-modernization bill. It’s about upgrading transmission lines to improve efficiency, to improve reliability. It’s about reducing grid congestion. We’re hopeful legislators will see it that way.”

A congested electricity highway 

In North Carolina, as across the country, the transmission grid — the network of high-voltage lines designed to transport electrons across long distances — faces a confluence of challenges. For one thing, the grid is old: about 70% of today’s transmission lines were installed at least 35 years ago.

These aging conductors have much less capacity than newer ones, said North Carolina-based Maureen Quinlan, senior officer for energy modernization at The Pew Charitable Trusts. Old lines are also susceptible to failure from normal wear and tear as well as from extreme weather events like hurricanes and heat waves, causing ​“road closures” on the electricity highway.

“An element of the grid may go out, and you have to reroute the power,” Quinlan explained. ​“Detours are always going to be slower; you’re on smaller roads. That’s going to create inefficiencies.”

The resulting grid congestion from existing, interconnected power suppliers is one ​“today problem,” said Quinlan. A study from the consulting firm Grid Strategies estimated these bottlenecks cost consumers some $11.5 billion nationwide in 2023 because they force utilities looking to avoid congested areas to dispatch more expensive electricity than they otherwise would.

A second challenge for the present is the long line of projects waiting to merge onto the clogged highway that is the transmission grid. In North Carolina and throughout the Southeast, that ​“interconnection queue” is dominated by solar farms and battery storage.

As Duke and other utilities race to build power plants of all kinds to supply large data centers, manufacturing plants, electric vehicles, and more, the queue is poised to lengthen until the road is widened — that is, until the grid’s capacity is expanded.

“You already have a system that’s experiencing a lot of these constraints and backlogs,” said Quinlan. ​“That’s going to be compounded by growing energy demand.”

Addressing today’s bottlenecks helps utilities save money to address a hurdle for tomorrow: building brand new highways to bring large sources of energy, such as offshore wind, to population centers, such as the Raleigh-Durham-Chapel Hill area known as The Triangle.

That’s why experts are increasingly looking to advanced transmission technologies, which can quickly be added to the existing grid to allow it to carry more power.

“They can be deployed in a matter of months to a few years,” said Quinlan, ​“and they’re also very cost-effective. [Some] can pay for themselves in less than six months, so they’re seen as a bridge to these bigger transmission grid-level needs.”

The technologies include both hardware and software. Carbon composite conductors, for instance, are up to twice as efficient as traditional aluminum cables reinforced with steel, in part because they sag less when overheated. These modern lines are a key reason the Lee-Milburnie upgrade is expected to reduce the length of service interruptions by 10%.

Through a process called dynamic line rating, utilities can place sensors on lines to assess temperature, wind speed, and other factors, allowing significantly more power to flow under favorable conditions.

Installing advanced hardware is more economical than building new conventional transmission lines because it offers more bang for the buck, doesn’t involve new rights-of-way, and reuses some existing infrastructure. One recent study found that replacing conventional lines with advanced conductors nationwide would increase the transmission grid’s capacity by four times as much as only building new lines. Such ​“reconductoring” would also save $85 billion by 2035 compared to business as usual.

The Lee-Milburnie line, for instance, will allow 1,600 megawatts of solar and 260 megawatts of energy storage to connect to the grid in Eastern North Carolina. Duke also told regulators the project would bring $2.1 billion in benefits, The News and Observer reported.

Advanced software technologies are also money-savers. A pair of studies from Quanta Technologies and The Brattle Group shows such software could reduce energy costs nationwide by over $5 billion annually, a former chairman of the Federal Energy Regulatory Commission wrote in a Utility Dive opinion article last year. However, he wrote, ​“a policy vacuum” in the U.S. is holding back adoption.

Filling the policy vacuum 

From Arizona to Maine, there’s growing bipartisan interest around the country in filling that void. Just this week, South Carolina Gov. Henry McMaster, a Republican, signed a bill requiring utilities to report on their advanced transmission efforts.

Advocates made some headway in North Carolina last November, when the state Utilities Commission approved Duke’s long-range carbon-reduction plan.

Regulators wrote in their decision that they believe that grid-enhancing technologies ​“can be used to overcome interconnection limits, address transmission outage challenges, and interconnect resources while transmission system upgrades are being constructed.”

Commissioners ordered that Duke’s next plan, a draft of which is due in September, report on the utility’s progress toward implementing such technologies, including explanations for not proceeding with any grid enhancements it evaluated.

Legislation sponsored by Rep. Kyle Hall, a Stokes County Republican who co-chairs the House Energy and Public Utilities Committee, would set that directive into law. 

“That makes it more durable,” said Cassie Gavin, director of policy at the North Carolina Sustainable Energy Association.

The proposed legislation, House Bill 814, also takes the order a step further, asking Duke to examine a full suite of advanced transmission technologies, including hardware modernization and new software.

Gavin’s group has long supported energy efficiency, she said, and promoting advanced transmission technologies is a logical next step.

“This is like energy efficiency for the grid,” she said. ​“And it can benefit ratepayers at the same time, so it seems like a no-brainer.”

Still, HB 814 as written won’t be eligible to advance for the rest of the General Assembly’s two-year session since it failed to pass the House by May 8. The bill also has yet to be discussed by a single legislative committee.

Duke, which holds significant sway in the Republican-controlled legislature, hasn’t taken a public stand on the legislation.

However, the utility has previously expressed concern about challenges posed by grid-enhancement technologies. During its planning process last year, the company told regulators that such tools could ​“contribute to operational complexities and reduced situational awareness.”

Asked recently about Duke’s position, a company spokesperson told Canary Media: ​“We appreciate the importance of discussions around ensuring safe and reliable power infrastructure to serve our customers in North Carolina and will continue to work with policymakers and other state leaders toward that goal.”

Official legislative deadlines notwithstanding, North Carolina lawmakers often combine an array of energy policies into one grand compromise bill; that’s how they passed the state’s bipartisan climate law in 2021. So, advocates remain hopeful that if there’s enough political will, there will be a way.

“We’re cautiously optimistic,” said Quinlan. ​“We look forward to finding a path forward to promote [advanced transmission technologies] in the state as part of its energy future.”