Can AES rally utility support for dynamic line rating?

In the face of massive near-term load growth, utility strategies vary widely. While some have decided to build new gas infrastructure, a small but growing cohort is instead turning to a suite of tools to expand the capacity of the existing grid.

In a report released in April, the utility and power generation giant AES Corporation detailed its own deployments of one such technology: dynamic line rating.

• The top line: AES and the dynamic line rating company LineVision installed 42 sensors across a mix of high capacity and local transmission lines in Ohio and Indiana, targeting improved reliability and the opportunity to connect step-load customers (which AES defines as those bringing “material” amounts of load in a single new connection, like data centers or industrial loads.) It took just two weeks to install the entire fleet of sensors, and to get the system, which uses real-time and forecasted conditions to continually calculate the thermal carrying capacity of lines, up and running.
• The market grounding: AES owns and operates two utilities in the U.S., both of which are experiencing immense industrial load growth: the vertically integrated AES Indiana, in MISO, and AES Ohio (formerly Dayton Power & Light) in PJM. But the company is also concerned about whether power generation customers outside that relatively small  utility footprint — namely data centers in places like Virginia — will be able to access the power they need. Demonstrating the potential of DLR to the utilities serving those AES customers was a key part of the impetus for this case study.
• The current take: Alexina Jackson, VP of strategic development at AES, said that deploying solutions like DLR at scale would happen much faster in a “less combative” and more collaborative environment. “We’d love a much more collaborative solution where the system operator, the utility, the developer and the customer all come to the table and say ‘we need energy, we need it yesterday, and here are the things we might be able to do to solve some of the constraints in the transmission system,’” Jackson said. “I think that would go a long way to scaling these solutions.”

The case study comes at a moment when awareness of DLR — and GETs more broadly — is beginning to grow. In light of a recent Department of Energy analysis, for instance, head of the Loan Programs Office Jigar Shah emphasized that developing dynamic line rating at scale across the country could unlock at least 10-30% more grid capacity, for less than $10 billion of investment.

Hudson Gilmer, co-founder and CEO of LineVision, told Latitude Media that the AES case study is both a symptom of that awareness of DLR’s potential, and of the desire to spread the word further.

“I think it's been under the radar until maybe the last six or nine months,” he said. “It's gone from being kind of a technology that the R&D departments [of utilities] have been piloting, to now being something that's being deployed.”

Utilities, Gilmer added, begin to take the technology seriously when peers like AES do. 

Deployment takeaways 

DLR is ultimately a visibility tool, said Jackson at AES, not just into carrying capacity, but also into the overall health of a line and problems with individual segments.

The first of the five guinea pig lines — a high voltage line in a region where AES is anticipating two significant additions of load, plus new solar generation — saw an average of 61% increase over static capacity. It also demonstrated a 32% increase over ambient adjusted ratings, which take into account certain environmental conditions but not things like physical line conditions or wind speed.

That first line is representative of a “no-regrets” upgrade, AES concluded in its report. DLR is particularly well-suited to these kinds of higher voltage lines because they are higher off the ground, and therefore have better cooling and fewer challenges from vegetation. They also move less and run straighter.

The utility also emphasized that DLR can be deployed much more quickly and cheaply than reconductoring, and without the requisite outage time.

“If a load growth, reliability, congestion, or similarly beneficial narrative supports the comparatively modest investment in DLR technology, these types of lines present a use case for rapid scaling for the U.S. electrical grid,” AES wrote in the report. “Indeed, when compared to traditional solutions to increasing carrying capacity, DLR is a powerful option.”

One major takeaway, according to Gilmer, was that DLR can pinpoint problems. For instance, one lower-voltage line had a segment where capacity increased by less than expected. A look at the data suggested that the bottleneck was the result of a “narrow, low-wind, and high vegetation corridor. 

“So by doing some additional trimming of the vegetation in the right-of-way, they will be able to increase the total capacity on the entire line,” Gilmer added. “But that wouldn't have ever known that without seeing the data from dynamic line ratings.”

Other lines were chosen for their proximity to critical generation sources at risk of curtailment, and to impending load growth. The study found that lower voltage lines and older poles, however, present some unique challenges. For example, older wood poles are more prone to movement than steel tower assets, complicating measurements of sag caused by movement versus by temperature.

A range of utility responses

According to Gilmer, it can be a 12-month-long process for a utility to first operationalize DLR: “it's not an insignificant lift.” 

And part of that lift is the shift in mindset required, he added, to go from the way they’ve operated lines for a century, to trusting a series of sensors. While AES is certainly ahead of the curve when it comes to utility deployments of DLR, Jackson said other utilities are starting to take notice.

“My experience in talking with other utilities is that there are a certain number that are out in front and forward leading,” she said, nodding to National Grid, and Portland General Electric as examples. (AES actually met LineVision through National Grid’s investment team, she added.)

Gilmer pointed to the Pennsylvania utility PPL as being among the first to put DLR on the radar of utilities, after the company won a major industry award for a DLR project last summer.

Meanwhile, there are utilities that are in the “early learning stages” and aren’t ready to take a position on the tech, despite the chorus of external enthusiasm. Many of those utilities have reached out to AES to ask questions about the DLR deployment.

“There’s a really good cohort of utilities that are curious and interested in learning about DLR,” Jackson said. “That doesn't mean they’re ready to deploy it tomorrow unfortunately, but at least they’re open to it.”

However, there’s also a group who “don’t really want external influence because there's a lot of sense of ownership over what they might consider to be their own lines,” she said. Those utilities are less collaborative, and less interested in talking to AES.

Ideally, Jackson said, developers would have open lines of communications to the utilities that service their load customers; it’s a conversation that’s essential to nearshoring efforts and AI growth in particular, she added.

For the most part, though, despite AES’ efforts to spread the DLR gospel, those conversations are still not happening.

“We need to find solutions to connecting those customers and corresponding energy to the grid,” she said. “We as renewable developers would love to be able to have those productive conversations with the line owners and help get these [grid-enhancing] technologies into the grid.”