On Sept. 29, the U.S. Department of Energy’s Office of Electricity selected the Thayer School of Engineering and electric utility provider Eversource for up to a $47.7 million grant, pending a finalized agreement. The project will deploy dynamic line rating technology, which adjusts the amount of electric power that can be transmitted on power lines using real-time data, across the 4,000 miles of Eversource’s transmission network in Connecticut, Massachusetts and New Hampshire. Eversource and Thayer hope to finalize the terms of the grant in the first quarter of 2027.
The project is one of 31 federally funded grid-improvement projects that will be constructed in 26 states as part of the DOE’s Speed to Power through Accelerated Reconductoring and other Key Advanced Transmission Technology Upgrades initiative, according to the DOE’s press release. The initiative is funded by the Infrastructure, Investment and Jobs Act, signed by former President Joe Biden in November 2021.
The 31 projects will receive $5.25 billion in total, $1.9 billion of which will come from the DOE and $3.35 billion from recipient cost-share funding with utility companies, according to the website. The projects aim to “improve grid reliability and lower electricity costs for approximately 100 million Americans,” according to the DOE’s press release.
In an interview with The Dartmouth, Thayer professor Junbo Zhao said he worked “extensively” with Eversource researchers to improve grid reliability at the Eversource Energy Center at the University of Connecticut before joining Thayer last year. Their collaboration included a pilot program that deployed dynamic line rating sensors in one transmission circuit in Cape Cod, Mass.
The pilot was a “very interesting foundation,” Zhao said. “We saw the benefits of deploying those technologies to help the grid, and this new DOE opportunity seemed to be quite a good opportunity for us to scale it up.”
The Eversource-Thayer project, called “Dynamic Rating Enhancement Advancements and Modernization,” scales the previous dynamic line rating pilot project to Eversource’s service territory in Connecticut, Massachusetts and New Hampshire. The total value of the project is expected to be approximately $95.5 million dollars. Half of that cost is supported by the SPARK funding from the DOE.
Eversource economic analysis and transmission strategy director Ben D’Antonio said Eversource viewed the SPARK program as an “opportunity to advance” the dynamic line rating technology “across our entire service territory in all three states.”
“The current proposal takes the same idea” as the pilot and applies it “network-wide,” D’Antonio said. “We would install sensors on approximately 10% of our transmission towers and use modern communication infrastructure to give us wide-area awareness.”
Transmission line ratings determine the amount of power that can be transmitted through the power line without risking reliability or damage to line infrastructure based on thermal limits, according to a Federal Energy Regulatory Commission whitepaper.
Typically, these line ratings are typically determined by “conservative assumptions about worst case, long-term air temperature and other weather conditions,” which can lead to “under-utilization” of the electrical grid, according to a FERC news release.
ISO New England, the independent non-profit that operates New England’s electrical grid, previously used seasonal line ratings that were set twice a year under weather condition assumptions for summer and winter.
After FERC mandated transmission providers incorporate ambient-adjusted ratings, which consider ambient temperature and other weather forecasts, into their electricity markets in December 2021, ISO-NE announced they will start using hourly ambient-adjusted ratings on Nov. 19, 2026.
“The ISO is updating software such that equipment owners can provide ratings on an hourly or shorter basis” and “accept real-time and forecast ratings from equipment owners that install dynamic line ratings,” according to Emma McCorkindale, a spokesperson for the ISO-NE.
Dynamic line rating — the technology used by the new Eversource-Thayer project — is more accurate at calculating the thermal limits of transmission lines than the ambient-adjusted rating requirement, according to Zhao.
“Dynamic line rating normally allows you to deliver more power along existing transmission lines compared to ambient-adjusted ratings,” he said.
The technology is expected to “reduce congestion, lower prices and ensure reliability” for consumers, according to D’Antonio.
“The grid is designed with a degree of conservatism and redundancy to ensure safety,” he said. “That conservatism can sometimes mean that there is unused capability on the grid. This technology gives us the opportunity to unlock the unused capability on the grid when weather conditions allow, and to send more power over the same infrastructure.”
Zhao said these infrastructure updates will also “accelerate” the process of adding “large loads” such as artificial intelligence data centers, large facilities and renewables to the grid.
“We see a strong need to accelerate interconnection and better utilize the existing capacity, because you cannot wait another five or seven years to build a new transmission line before those data centers or renewables can come in,” Zhao said.
The award is the start of a four-year project. Work will start with finalizing the grant agreement with the DOE, preparing sensor software and communication systems and identifying sensor deployment locations, according to Zhao and D’Antonio.
Thayer professor Erin Mayfield, who studies energy systems planning, wrote in an email statement to The Dartmouth that DOE programs “advance multiple policy objectives,” including modernizing grid infrastructure, improving grid reliability, managing capital investments in new energy generation, regulating electricity rates and strengthening energy security.
“With load growth from data centers and electrification, these programs are especially important,” she wrote. “The intention is for [the] government to help catalyze private investment by absorbing some of the upfront cost and risk.”
