Why does the power go out during extremely cold winters?

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A brutal winter storm brought Christmas chaos and misery to millions of Americans as intense snow, and frigid cold gripped parts of the eastern United States. The extreme weather has severely taxed electricity grids, with multiple power providers urging millions of people to reduce usage to minimize rolling blackouts, highlighting the vulnerability of power systems equipment in such extreme weather.

One might wonder why the power goes out when it’s just so cold outside.

Power outage during cold weather

The electric system consists of thousands of components that are mostly electromechanical, with lots of moving parts. There is a range where these components work best. When the weather gets too cold or hot, or humidity levels go beyond the range, the electrical system will not be as efficient. Those moving components will need to work just a little harder to achieve the same result as they would on a more favorable day. It doesn’t help that our infrastructure is aging, making it more difficult for the electrical system to respond to extreme weather occurrences.

Ice on power lines

Winter weather often features storms and blizzards. Ice and snow can accumulate on power lines and tree branches, which can cause them to break or fall onto the lines, leading to power outages. Even if there is no snow or a blizzard, tree roots cause a problem by providing a pathway for ice to build up around underground power lines disrupting the flow of electricity. In cold weather, a warm transformer can be very inviting to a small animal or bird, which can result in malfunctions.

Increased demand for electricity

As temperatures drop, people use more electricity to heat their homes and businesses. This can strain the power grid, especially if the electricity demand exceeds the capacity of the grid to produce and distribute it. If temperature extremes are worse than forecast and/or happen faster than predicted, utility companies may not have enough time or resources to meet the increased demand for electricity. This can lead to local or widespread overloads, resulting in automatic service outages or rotating blackouts in some neighborhoods.

In recent years, more people have been using solar panels to generate their own electricity. However, during bad weather, the output of these devices is reduced and increases the amount of energy the utility must supply, making the problem even worse. Additionally, customers who generate energy from these devices hide the actual energy demand of a residence or building from the utility. This makes it difficult for them to know how much power they must be able to supply instantaneously when those self-generation sources go offline or are substantially reduced.

To prevent power outages during cold or hot weather, utility companies need to take steps to improve power system operation. Ensuring that power plants are properly insulated, replacing aging infrastructure, adding additional status monitoring equipment, and improving load forecasting for given weather environments are some steps that can be taken.

Implementing these measures comes at a cost, particularly if it involves replacing aging infrastructure. However, failing to address these issues can lead to more frequent and catastrophic power outages. Any last minutes fixes would be not only inefficient but also costly for the people.