An unprecedented 1.4 million homes and businesses lost power when Hurricane Helene pummeled the Palmetto State, uprooting trees and power poles and inflicting catastrophic damage to South Carolina's electrical grid.
About a fifth of those customers remained in the dark a week after the storm, despite the efforts of thousands of line workers who toiled around the clock to restore power as quickly as possible.
In the aftermath of Helene, some have asked whether South Carolina would be better served burying its electrical lines, where they're protected from powerful winds and falling trees, rather than spending weeks rebuilding the state's above-ground power infrastructure after major storms.
Studies have found a positive correlation between the share of a system's power lines that are buried and its reliability, but the high cost of burying lines often limits the practice.
During a press conference last week, Gov. Henry McMaster signaled his openness to the possibility of burying more lines, calling it a "great idea," albeit one that comes with a considerable price tag.
"One thing we've learned is that it would be nice to have a lot of power lines buried," the governor said. "But that is expensive."
While much of the public discourse about burying power lines has focused on the extraordinary cost, which varies widely based on circumstances but is generally multiple times more expensive than running lines above ground, utility industry officials say there are other factors that sometimes make burying lines impractical.
"I think there's this view that if we just buried lines we would minimize impact to infrastructure, we would minimize the impact of outages. And that's not totally accurate," said Scott Aaronson, senior vice president of security and preparedness for the Edison Electric Institute, a utility industry trade association. "There are certain use cases and risks that really do lend themselves to undergrounding. But, I always caution folks that undergrounding lines is not a panacea."
In addition to the upfront expense of burying lines, which typically gets passed on to customers through higher rates, utility officials caution that buried lines are susceptible to water incursion and take longer to repair when damaged.
"There is nowhere that you can locate power lines where they will be completely protected from interaction with the environment," said Ted Kury, an economist who serves as director of Energy Studies for the Public Utility Research Center at the University of Florida. "Wherever you locate them, they're going to be vulnerable to certain types of damage."
For many people, especially those who rely on electricity to power their medical devices or refrigerate life-saving medicines, extended power outages are more than just a temporary inconvenience.
Studies show the loss of worker output and business production from severe weather-related power interruptions costs the U.S. economy tens of billions of dollars each year.
With rising temperatures expected to increase the frequency and intensity of extreme weather,such costs are only likely to rise.
State Rep. Justin Bamberg, D-Bamberg, a proponent of the targeted burying of power lines, said he thinks it's past time South Carolina considered a different approach than repairing, and in some cases rebuilding, the above-ground power grid after major storms.
"Burying lines is very costly upfront," he said. "But how much will you save over decades and how much will the citizens in the state save over decades if we have more lines that are buried and not aerial anymore?"
To answer that question, Bamberg is proposing the creation of a study committee to assess the feasibility of burying power lines throughout the state.
In 2021, the state's Office of Regulatory Staff, which represents the interests of South Carolinians with respect to public service utilities, published a report examining the resiliency of South Carolina's electric and natural gas infrastructure. While the report recommended strategically burying some of the state's power lines, among other things, it didn't put forth a plan for doing so or identify areas that would most benefit from line burial.
Bamberg, who favors a more comprehensive analysis of underground power lines, is hoping to put together a bipartisan group of lawmakers who support studying the issue to work with House leadership on language for a bill in advance of the 2025 legislative session.
"If the answer ends up being that it's not financially feasible to do, then so be it," he said. "But at least we're not just guessing."
When asked if the governor would support launching a committee to study underground power lines, a McMaster spokesman said all options for strengthening the state's power grid were on the table.
Burying power lines isn't a new concept.
As of 2007, about 18% of power distribution lines nationwide were underground, according to a study by the Edison Electric Institute that represents the most up-to-date publicly available information on the subject.
Many cities and towns, including several in South Carolina, went subterranean years ago.
Hilton Head Island, for example, has a fully underground power system.
The Palmetto Electric Cooperative began replacing the town's overhead distribution lines with underground equipment in 2004. The 17-year project, which cost nearly $35 million, was funded primarily through small service fees -- roughly $3 or $4 per household -- that were added to customers' monthly bills.
"It was a very forward-thinking project and I think we're seeing the anticipated benefits come to fruition now," Hilton Head spokeswoman Heather Woolwine wrote in an email last week.
Few municipalities have taken Hilton Head's wholesale approach, but many towns strategically bury portions of their electric distribution systems or require that the lines feeding new developments are placed underground, both for reliability and aesthetic reasons.
While it typically makes financial sense to bury lines at greenfield sites, where the ground is already being torn up for new construction, underground lines are neither cost-effective nor appropriate in all situations, said Aaronson, the industry trade group official.
Some areas, due to their risk of flooding, their topography or the distance between customers, simply do not lend themselves to underground lines, he said.
For that reason, power companies do not view underground lines as their "default" solution, but rather one of multiple tools in their resiliency toolbox, explained Jeff Brooks, a Duke Energy spokesman.
While he said the company may consider burial when it identifies a portion of overhead line that experiences frequent non-storm-related reliability problems, in many cases Duke favors other grid-hardening and resiliency methods, such as vegetation management, pole replacement and the use of smart technology.
"Our goal is to deliver reliable service, but also keep rates as low as possible for customers," Brooks said. "It's prudent for us to make smart decisions about providing the best service in an area. Placing a line underground is often not the most effective solution."
Rather than relying on a one-size-fits-all approach to resiliency, power companies are increasingly using data to inform decisions about which grid-hardening methods make the most sense in a given scenario.
Over time, as extreme weather risks intensify and new technologies emerge, utilities will continue to reassess and redesign their solutions to meet the evolving needs of the communities they serve, Aaronson said.
"It's not this static thing," he explained. "We are constantly as a society re-evaluating the costs of infrastructure, the risks to it and the cost of either doing something or not doing something."
In that respect, a study committee of the sort proposed by Bamberg, the state lawmaker, could prove valuable if it provides data that helps stakeholders make more informed decisions about how best to fortify South Carolina's power grid for the future, he said.
"Anything that supports a partnership between policymakers, regulators and electric companies is helpful in deciding what is the most prudent set of investments for customers and communities," Aaronson said.
Kury, the energy researcher at the University of Florida, said the greatest advances he's seen in resiliency over the past decade-plus have to do with this sort of communication and collaboration.
Rather than reserving discussions of power grid resiliency for the immediate aftermath of major storms, stakeholders today are more likely to keep those conversations going outside of hurricane season and to welcome participation from a variety of groups, he said.
"To me, that's real progress," Kury said. "Because you're not going to figure out what the best solution is for you unless you're talking with all of the people about it."