The United States faces a pressing energy challenge: how to ensure people have reliable and affordable electricity when deadly storms hit.
This need came into sharp focus last weekend when a powerful winter storm swept across Texas up to Maine, bringing with it heavy snowfall, freezing rain and subzero temperatures. It caused blackouts to more than 1 million customers, especially in Tennessee, Mississippi and Louisiana. Many are still without power.
Preparations made by utilities and grid operators — including staging extra line crews, positioning equipment in high-risk areas and ensuring backup generation and reserves were on standby — certainly helped prevent further widespread outages during Winter Storm Fern. The bigger challenge now is long-term: reducing the number of blackouts by making power systems more reliable and still affordable in winter storms, and extreme weather in general.
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Kelly Lefler, Senior Manager, Grid Decarbonization and Markets, WRI U.S. Polsky Energy Center |
WRI energy expert Kelly Lefler outlines what’s needed to strengthen the reliability of the electricity system and ensure people can count on constant, affordable power in the face of increasingly erratic weather.
What is mostly behind the power outages during Winter Storm Fern?
Utilities and regulators will assess records and publish official reports of what happened in the coming weeks and months, but for now it seems that the outages were largely due to the icy conditions affecting distribution and transmission systems. Ice from the storm built up on trees and the added weight caused them to snap, toppling power lines. The ice can also build up on the lines themselves and bring them down.
Also, in eastern U.S., some power plants couldn’t produce as much electricity because of the extreme cold and limited natural gas supplies, forcing them to shut down or run at reduced capacity. The region relies on natural gas pipelines along the East Coast, which are historically constrained during very cold weather. As a result, there were nearly 21 gigawatts of generation outages, with most of that capacity forced offline. To put that into perspective, 21 gigawatts is the same as 21 billion watts, enough to power millions of homes at the same time. Importantly, these disruptions did not require grid operators to impose rolling blackouts to prevent larger system failures.
What makes the US electricity system vulnerable to extreme cold weather?
Winter storms tend to stress the electricity system — from power plants to transmission lines and distribution networks — in predictable ways that create an imbalance between supply and demand of electricity or make it harder to maintain safe grid conditions. When that happens, grid operators may be forced to take some electricity demand offline to prevent a larger, uncontrolled outage. While every major winter blackout has its own story, a few common failure points show up again and again.
In extreme cold, one of the biggest challenges is getting fuel to power plants for electricity generation and to homes for heating. Natural gas is the U.S.’s largest source of electricity generation, providing 43% of electricity as of 2024. During winter storms, demand for natural gas spikes as people turn up thermostats, while power plants also need the fuel to generate electricity. This simultaneous surge, known as coincident peak, is a well-known planning challenge. Extreme cold can strain the natural gas system beyond normal operating conditions, making it harder for gas-powered generators to access fuel when they need it the most. Similar stress can happen during extreme heat, when air conditioners drive up electricity demand.
Another issue is lack of proper winterization — preparing equipment for wintry conditions — across different parts of the electricity system. Equipment that isn’t prepared for extreme cold, such as power plants, sensors and natural gas wells and pipelines, can freeze or malfunction. When multiple pieces fail at once, utilities may have no choice but to implement widespread outages to maintain system safety and prevent cascading failures.
Winter conditions also make it harder for crews to maintain or repair equipment as problems arise, increasing the risk of outages.
Transmission and distribution systems can also be affected by winter storms. Ice and heavy snow can damage power lines, reduce their carrying capacity or cause mechanical problems, making it harder to move electricity from where it is generated to where it is needed — even when enough power is available. These lines are especially vulnerable without regular maintenance. For example, trimming trees near power lines is critical to prevent ice-laden branches from falling on them, as has happened during Winter Storm Fern.
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How can energy systems be made more reliable and affordable during weather shocks?
There are several ways that energy systems can be made more reliable ahead of winter storms and extreme weather. Greater reliability helps prevent supply disruptions, eases pressure during peak demand periods and can keep power more affordable.
One of the key ways to make energy systems more reliable is by maximizing flexibility — improving how well the system can adapt in real time to changes in supply and demand. The more flexible the system, the better it can handle sudden demand spikes in the event of extreme weather, such as cold snaps or heat waves, or respond to supply disruptions such as plant outages.
Improving flexibility includes upgrading aging infrastructure. Much of the U.S. grid was built decades ago under different demand patterns. Modernizing the grid — by updating substations and transmission equipment, deploying advanced sensors and incorporating advanced transmission technologies (ATTs), for example — can reduce failure rates during extreme heat and cold. These technologies help operators detect problems quicker, reroute power if equipment is damaged and restore service fast. Modernization not only improves reliability but also reduces expensive emergency interventions and lowers long-term maintenance costs.
Increasing grid capacity, both through deployment of ATTs and building regional and interregional transmission lines, can reduce the risk of a local weather event turning into a widespread outage. Creating a more interconnected grid allows regions to share power during shortages. Having this greater transmission capacity also help keep prices down by allowing lower-cost electricity to reach areas facing higher demand.
Demand-side management options can help ease pressure on the system during extreme weather events. These include encouraging customers and large users to reduce or shift electricity use during peak periods in exchange for lower bills or leveraging distributed energy resources to help prevent shortages.
Systems that rely too much on a single fuel are more vulnerable to disruption. Diversification across energy sources and technologies helps reduce the risk of issues related to fuel shortages, infrastructure failures and localized weather impacts.
Finally, policy is also critical. It’s vital that incentives are properly aligned with modern needs for flexibility and preparedness. This can help utilities make system investments that really work in extreme weather and minimize costs to consumers in both the short and the long run.
What role, if any, can clean energy play?
While renewables are weather-dependent, broad geographic dispersion and forecasting allow them to contribute meaningfully during winter storms. Wind and solar generation tend to be available during many extreme cold events, even when other resources are strained.
In several recent cold-weather events, renewable generation was available when needed, even as some fossil fuel units were forced offline because of freezing equipment or fuel supply constraints. For example, during Winter Storm Elliott, only 7% of unavailable generating capacity came from clean energy resources — that’s wind, solar, nuclear and hydro combined. And in some parts within the impacted region, wind and solar exceeded forecasts.
Clean energy also supports diversification. Adding a broader mix of energy sources reduces dependence on a single fuel or delivery system that may be disrupted during extreme weather. Resources that do not rely on “just-in-time” fuel delivery, in which power plants receive fuel only when it is needed, can reduce exposure to fuel shortages when supply chains are strained.
