A winter storm is heading to Texas. Here’s what that means for the power grid.

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A winter storm is expected to hit Texas as soon as Wednesday night and it could give the state’s main power grid, which delivers electricity to most Texas households and businesses, its first significant test since last year’s devastating winter storm caused massive dayslong blackouts across the state.

The Electric Reliability Council of Texas, which manages the grid, issued a winter storm watch through Sunday, saying it expects high energy demand through the duration of the cold front. But even with sleet, snow and ice predicted for a large swath of the state, ERCOT says it has sufficient power generation to meet the anticipated demand.

Gov. Greg Abbott and other Texas leaders said they don’t expect the power grid to have systemwide issues like last year, when hundreds of people died during a mid-February winter storm. But Abbott, who two months ago promised the lights would stay on this winter, hedged on Tuesday when he said nobody can guarantee there won’t be local power outages throughout Texas.

Power generator companies are closely watching whether natural gas companies will be able to continue producing enough gas to send to power plants throughout the severe weather, an issue some generators experienced over New Year’s weekend when a brief cold front led to a drop in natural gas production. The reductions didn’t lead to any power outages.

ERCOT has told entities in the power grid supply chain that gas suppliers have notified some electricity generators that some of their expected gas supply will not arrive this week during the freezing weather.

Preparing for a possible emergency, ERCOT has also discussed whether to ask residents to reduce their electricity use. Asking consumers to cut back on power is the first step the grid operator takes to reduce strain on the grid.

Here’s what you need to know:

Why would ERCOT ask for power conservation in this situation?

When the temperature falls and Texans crank up their heat at home, the resulting spike in electricity demand can result in “tight” grid conditions — when demand edges close to the maximum electricity supply at any given time. Power grids must keep supply and demand in balance at all times. When Texas’ grid falls below its safety margin of excess supply, the grid operator starts taking additional precautions to avoid blackouts. The first precaution is to ask the public to cut back electricity usage.

Could we see a repeat of last February’s disaster?

It’s too early to tell, but energy experts and executives have warned about weaknesses in the state’s natural gas system, which fuels a majority of the power generation in Texas.

If the natural gas supply is not functioning at full strength during below-freezing temperatures, the many Texas power plants that run on gas will not be able to produce the amount of electricity they’re expected to produce for the grid. A fairly typical cold front on New Year’s weekend caused natural gas production in the Permian Basin — Texas’ most productive oil and gas region — to drop by roughly 20%, but no major power disruptions were reported.

Abbott in November guaranteed the lights would stay on this winter. Political communication and energy experts said his promise was centered around his reelection campaign, not the actual readiness of the state’s power system.

On Tuesday, Abbott hedged his guarantee.

What did the Legislature do to fix the power grid, and could any of it help this week?

After the February blackouts, Texas lawmakers passed energy grid legislation aimed at preventing electricity blackouts, but it will likely take years before those changes are fully implemented.

Senate Bills 2 and 3 included a few key changes to the state’s power grid that experts said will begin to address some issues, such as requiring power companies to upgrade their plants to withstand more extreme weather and creating a statewide emergency alert system.

But the legislation said power regulators needed to ensure all power plants were weatherized, a rule the Public Utility Commission adopted this fall. Meanwhile, lawmakers approved legislation that said oil and gas companies did not need to be weatherized until 2023.

The legislation also changes ERCOT’s governing board to replace what lawmakers called “industry insiders” with appointees selected by a committee comprising selections by Abbott, Lt. Gov. Dan Patrick and House Speaker Dade Phelan.

What about the natural gas supply?

A majority of the state’s power generation runs on natural gas. But lawmakers wrote different rules for the natural gas industry compared to the electricity industry. The gas industry is not yet required to be weatherized.

A new committee created by lawmakers in the spring has until September 2022 to identify and map the state’s natural gas infrastructure. Then, the Railroad Commission of Texas, which regulates the state’s massive oil and gas industry, will draft its weatherization rules for natural gas infrastructure.

The Railroad Commission recently finalized a new rule that will ensure gas producers likely won’t get their electricity cut off, which is what happened last February due to paperwork errors. Natural gas producers blamed a lack of electricity for a massive drop in natural gas production during the winter storm last February.

Should I get a portable generator for my home?

Here’s a list of things Texans can do to be ready for another extreme winter storm. But be careful with portable generators, which are among the deadliest consumer products.

Portable generators can save lives after major storms by powering medical equipment, heaters and refrigerators when the power goes out. But some desperate Texans who improperly use generators to power their homes after last year’s winter storm died of carbon monoxide poisoning.

Carbon monoxide is particularly dangerous because it is odorless, colorless and tasteless, and it can kill within minutes at high levels. Those who survive may suffer brain damage and other long-term health problems.

The best way to detect if you have unsafe levels of the poisonous gas in your home is to have a working carbon monoxide monitor, which will sound an alarm if you’re in danger.