Low-Energy Fridays: What did Winter Storm Fern teach us about electric reliability?

Major power outages generate a lot of discussion about power plants: What did wind or solar or fossil fuel generators do (or fail to do)? But that was beside the point when Winter Storm Fern hit in late January, as distribution infrastructure (i.e., local power lines that run through neighborhoods) posed the biggest problem. As little as half an inch of ice can be enough to take down a line and leave a neighborhood without power. Add ice-covered trees and high winds to the mix, along with vehicles slipping on icy roads and hitting utility poles, and power lines are at high risk.

When Fern blew through Nashville, it cut off power to almost half of the city’s residents. While tens of thousands of line workers mobilized nationally, the extent of the damage meant full restoration would be a slow, grueling process. Two weeks after the storm, a few Nashville residents remained without power. Similar stories played out along the storm’s track from New Mexico to the Atlantic Coast.

The storm stressed every part of the power system. Heating demand surged, several transmission lines went down, and a few power plants were knocked offline. Fortunately, grid operators managed those difficulties without customer outages. It was the distribution infrastructure—the “last mile”—that caused the problem.

Apparently, the Department of Energy (DOE) did not get the memo. During the storm, the agency issued 20 new “Section 202c” emergency orders, each one aimed at squeezing a little extra power from electric generators. (Sec. 202c of the Federal Power Act gives the secretary of energy emergency authority to respond to grid reliability threats.)

That same authority was used to block several fossil fuel plants—including three Midwestern coal plants—from retiring last year. A DOE statement claimed that keeping these three plants from retirement allowed them to provide “essential power” that saved “hundreds of American lives.” But this claim strains credulity, given that no customers lost power for lack of generation; in fact, the grid operator responsible for dispatching the plants didn’t ask the DOE for any help. Regardless of their actual value, the emergency orders pouring out of Washington, D.C. didn’t address Fern’s main pain point.

A storm causing that much damage requires triage: address the biggest failures first, and save the smaller ones for later. For the unluckiest few, the problem is a downed line between their home and a local distribution line. For the single home left in the dark while the rest of the neighborhood lights up, well … one is the loneliest number.

Most ice storm damage results from trees growing too close to power lines. There’s a hard political trade-off at the heart of this issue: Trees are valuable to the community, but so is keeping the lights on. Nashville’s electric utility was frequently recognized as managing that balance well; however, a recent internal audit highlighted oversight failures in its tree-trimming program. Was it bad management or just bad luck? Nashville city officials have launched an investigation to find out.

What can communities do? Storm damage to electric power’s last mile often sparks calls for undergrounding distribution infrastructure. An approach with its own challenging trade-offs, placing power lines underground is much more expensive than stringing them above ground. And although outages are less likely to occur, they take longer to repair when they do. In Florida, where hurricanes are a much larger concern than winter storms, utilities are required to consider undergrounding transmission and distribution lines in regularly updated Storm Protection Plans. The assessments in these plans still point to building most distribution infrastructure above ground.

While utilities and regulators debate how much to spend hardening distribution infrastructure, some consumers aren’t waiting. One company maintains small natural gas generators on-site at large grocery stores and for other commercial customers that support the regional grid most of the time but are available to keep the store or office fully powered in the face of a local power outage.

Another company will install a battery for residential customers, managing it as a grid resource most of the time but supplying the customer with power during an outage. The company reported that over 350 customers’ lights stayed on throughout the storm thanks to these batteries. This “do-it-yourself” reliability raises a question that regulators have long treated as settled: If customers can buy their own resilience, how much should everyone else pay to provide it for them?

Washington spent Winter Storm Fern issuing emergency orders to keep generators running. But for the customers left in the dark, power generation wasn’t the problem—it was the fragile last mile of wire between them and the grid.