In a landscape white with snow and ice, a drone flies high among transmission towers, trailing a heavy insulated rod suspended from a long wire. As the drone twirls above the power lines, the rod hits the conductors, frosted with recent snow, scattering the white powder into the air. This mechanical de-icing, shown in videos circulating on social media, is one of many ways utilities and grid operators are protecting their power lines from ice and cold damage in the aftermath of Winter Storm Fern, which hit the country with record low temperatures earlier this week.
The storm put a spotlight on the work utilities and grid operators have been doing to improve resiliency and harden their infrastructure ever since Winter Storm Uri caused a catastrophic grid failure in Texas five years ago, and killed hundreds of people. Operators all over the U.S., including in ERCOT, weathered the immediate impacts of Fern relatively well, thanks in part to winterized power generation and new battery installations — and a measure of luck, given that there was more wind and less ice than predicted.
Still, the storm left more than 800,000 people without power, especially in the southeast, in large part because of the damage accumulating ice caused on poles and power lines.
As William Chisholm, an electrical engineering professor specialized in the adverse effects of weather on overhead power lines and an associate at the electricity services company Kinectrics, explained to Latitude Media, there are several ways ice can damage power lines. Accumulated ice can both weigh on power lines, making them sag, and take down vegetation, which can, in turn, fall onto live conductors and drag them to the ground, a risk that is especially high for distribution lines.
“Transmission lines are also vulnerable to the ‘galloping’, which occurs with a modest amount of ice on one side of the conductor, combined with steady, strong sidewind,” Chisholm added. “The lop-sided ice makes a kind of wing that can feed mechanical energy into a span. When the rotation of the iced conductor matches one of the ‘skipping rope’ frequencies, then we can see galloping so large that one conductor collides with another, causing a fault.”
Ice has always been a potential problem for power lines, but over the past few years, utilities have started approaching it with more urgency, in acknowledgment that extreme weather events, from winter storms to heat domes to wildfires, have become more frequent and impacted wider swaths of the U.S.
“Utilities are viewing all overhead line resilience, including ice loads, as a more urgent priority than a decade ago,” Chisholm noted.
Reactive solutions
Camilo Serna, SVP for strategy at North American Electric Reliability Corporation, says this shift reflects on how utilities are changing their approach to planning.
“In the past, we’ve always focused on resource adequacy, and we really think that’s not sufficient these days,” he said at a panel about extreme weather events that took place at the Power Resilience Forum in Houston last week. “These types of storms that we’re seeing are happening almost every year; before, they were happening every decade.”
As a result, utilities are incorporating a host of new technologies to improve their resiliency, including solutions to avoid ice damage. Some, such as the drones, simply substitute tasks previously performed by helicopter or by hand. (“But generally helicopter operations are about the same cost as drone operations, so this may take some time to see wide application,” Chisholm said.)
Other innovations involve advancements in AI and materials science, aiming to either prevent ice accumulation entirely or spot dangerous anomalies in a matter of seconds. In many cases, these products come from startups that had been working to increase grid capacity through dynamic line rating and other means, but have now expanded their offerings in response to utility demand.
Prisma Photonics, for example, detects anomalies including ice accumulation and galloping on power lines using the fiber optic cables used for communication and data that accompany transmission lines in the majority of the Western world. The Israeli startup was founded in 2017 and raised a $30 million growth round in October 2025, bringing its total capital raised to roughly $80 million.
Eitan Elkin, Prisma Photonics director of marketing, told Latitude Media that the company connects to the optical ground wire through a “boring” hardware box it places in substations, and then sends a light signal through the fiber. For the most part, fiber is transparent, but it does have microscopic impurities that reflect back some of the light. In case of anomalies distorting the line, like a lot of ice making it sag, the reflections take a particular, readable shape.
“We listen to these reflections,” Elkin said, explaining that because Prisma’s software knows how much time has passed between sending the signal and receiving back the reflection, it can pinpoint the location of the anomaly. “And we look at the optical signature, and using AI…we know if it’s ice, a wildfire, an electrical fault, or wind of four meters per second at a 45 degree angle.”
This allows the utility to quickly detect dangerous situations even in the remote areas where many of the transmission lines are located. Each installed box grants Prisma a visibility of 30 miles in each direction, meaning two connected units can monitor a 60-mile span. In the U.S., its technology is being deployed with utilities such as the New York Power Authority, Southern Company, and more recently PG&E, which is using it in its dynamic line rating and asset health monitoring demonstrations.
Meanwhile, LineVision monitors power lines using tower-mounted LiDAR sensors with a weather station inside, and counts utilities such as National Grid, PG&E, and Avangrid among its partners. The company specializes in dynamic line rating using both software and sensors, but as VP of product Emilie Tullis told Latitude Media, “there are so many additional insights that you can get” using DLR. “It is a much bigger story than just capacity.”
The company’s existing tools allow for “hyperlocal, downscaled weather at the actual conductor,” Tullis added. “It also allows us to monitor a 3D plot of the line, which helps us understand what the sag of the line is: Is it moving? Is it sagging more than we expected? In the case of icing, is galloping occurring?” (In the coming days, LineVision is launching a yet-unannounced new product that is expected to add grid visibility to its tech.)
Looking for preventive solutions
For Niall Coogan, co-founder and CEO of AssetCool, both of these solutions to ice loading are of the reactive kind: you spot a problem, and you go out to fix it, maybe with a drone in tow.
“But the area that we’re interested in is proactive: being able to mitigate upfront the potential for ice accretion,” Coogan said. “It’s about increasing operational headroom and making those isolated events that are going to be catastrophic or problematic even more improbable.”
AssetCool, a UK-based startup founded in 2018, develops a coating that increases power lines’ capacity by cooling them off. Now, it’s working on developing another product to reduce ice accumulation. “We get asked by utilities all the time if our main coatings reduce ice, or if we have a product that can,” Coogan said.
But it’s a challenge. As Coogan explains, ice-phobicity is often tied to repelling water: If you have less water on the line, less ice will form. However, the most effective water-repellant products are engineered with nano-scale spikes on the surface. These delicate structures are easily damaged every time water expands and contracts during freezing cycles. They don’t last long enough to make them economical for thousands of miles of overhead lines, as the cost of frequent replacement would outweigh the benefits.
“We’re working on some interesting things at the frontier of materials science that can demonstrate an ice-mitigation effect both in a high-voltage environment and through many icing and de-icing cycles,” he said. “The aim is never really to have zero ice on the lines. But if you could reduce ice accretion by 25% or 30%, that has a pretty material impact on reducing the potential for these catastrophic effects.”
Coogan hopes to have results on this research ready by the end of the year.
