The recent deep, biting chill that froze the United States forced millions of furnaces to switch on at the same time, raising energy demand to new seasonal highs during one of the diciest times of year for power reliability.
In fact, the Tennessee Valley Authority — the federal power utility that covers states including Tennessee, Alabama, Mississippi, and Kentucky — set a new power demand record last week, not just for winter, but for all time.
The good news is that for the most part, the lights stayed on and toes stayed warm as most of the US avoided sweeping blackouts. But some homes in states like Oregon, Louisiana, and Kentucky did go dark amid the icy weather, while other regions came precariously close to shortages.
The cold weather makes these vulnerabilities clear, but it also reveals that wintertime energy demand is rapidly changing. As more homes switch to electric heating, winter electricity usage is rising faster than it is in the summer across much of the US, and that’s a mounting challenge for utilities.
Our current energy infrastructure is getting by — but just barely. And parts of the country have already seen what happens when it doesn’t hold up: Power outages across Texas during Winter Storm Uri in February 2021 contributed to at least 700 deaths across the state.
In power markets like PJM, which serves 13 Eastern states and the District of Columbia, winter energy needs are increasing faster than any other time of year — even more rapidly than the ever-hotter summers.
“In PJM, the highest electricity demand peaks are in the summer, but you will see that the long-term expected increase in the winter peak actually outpaces the growth in the summer peak,” said Jeff Shields, a spokesperson for PJM, in an email. “That is primarily attributable to the growth in electrification of heating systems.”
Why winter is becoming a trickier time for the power grid
In 2020, electricity met 44 percent of residential energy needs while natural gas, for appliances like stoves and furnaces, provided 43 percent. About half of total household energy demand goes to just heating and cooling. As temperatures dipped last week, natural gas demand for heating and power generation reached a new record high across the US — just as gas wells also froze and supplies hit a 13-month low, raising prices for both gas and electric heating. The main Texas electricity grid operator, ERCOT, asked customers to conserve power as the state crept toward new wintertime demand records.
Winters, it turns out, can be just as difficult for the power grid as summers, if not more so. The US experienced its highest electricity demand day ever last summer as scorching heat waves baked much of the country. Yet fans and air conditioners kept blowing because grid operators anticipated the heat and procured extra electrons months in advance.
Sudden cold snaps, however, can be harder to predict than heat waves. Hot weather takes time to build up, and cyclical weather patterns like El Niño can signal months in advance that severe heat is looming.
Cold weather, on the other hand, can set in fast, with Arctic cold fronts causing temperatures to drop as much as 50 degrees Fahrenheit within hours. Icy weather can literally freeze up fuel supplies and damage power lines while rapidly raising energy needs as people try to stay warm during a time of year when many utilities schedule downtime for power plants. That’s further worsened when a bout of chilly weather defies the historical patterns that utilities use to procure electricity generation.
“As observed in recent winter reliability events, over 20% of generating capacity has been forced off-line when freezing temperatures extend over parts of North America that are not typically exposed to such conditions,” according to the winter reliability assessment for 2024 from North American Electric Reliability Corporation, an energy industry nonprofit focusing on the power grid.
So while winter demand surges often aren’t as high as they are in the summer, scaling these peaks can be trickier, even as winters warm up overall due to climate change.
Switching to electricity is a key part of the US strategy for reducing the greenhouse gas emissions that cause climate change, and swapping oil and gas-burning furnaces for heat pumps and resistive heaters, which use electricity to generate warmth, is an important tactic. Cars that run on electricity rather than gasoline are also gaining traction, introducing new loads to the power grid. Over time, the overall effect is that greenhouse gas emissions and total energy use will go down — but along the way, electricity consumption will go up.
The US Energy Information Administration projects that US residential electricity demand will grow upward of 22 percent by 2050. To ensure fingers don’t go numb in the future, grid operators have to start planning now to keep electrons flowing and develop new tactics for allocating power in the bitter cold. Fortunately, the new generation of electric appliances provides more options for smoothing out power demand peaks and could improve overall grid reliability.
Texas learned from its last major brush with the cold
The 2021 blackouts across Texas during Winter Storm Uri, which cast a massive slick of cold, snow, and ice from Texas to Maine, illustrated just how many different ways cold weather can embrittle the power grid. Texas is the largest wind energy producer in the US and some Republicans were quick to blame renewable energy for the blackouts, but a report on the outages from the Energy Institute at the University of Texas at Austin put it bluntly: “All types of generation technologies failed.”
Frozen equipment and iced-up pipelines led to an 85 percent drop in natural gas production. Nuclear power plants malfunctioned. Coal piles froze solid. Wind turbines iced up. Snow blocked solar panels.
In addition, ERCOT failed to anticipate just how cold it could get in the Lone Star State. Though winters are generally heating up due to climate change, sudden bouts of cold are still possible, even in Texas. Many power producers had scheduled maintenance and downtime for their generators during the storm, anticipating a more typical warm Texas winter. “Traditionally the whole system and planning has been around meeting the summer peak,” said Carey King, a research scientist at the Energy Institute at the University of Texas at Austin who co-chaired the investigation into the 2021 Texas blackouts.
Solar generators also tend to produce much less electricity in cold seasons than on long, sunny summer days. Wind energy production can vary through the year, and in Texas, it tends to peak in the spring and dip in the winter. So there was less power available when Uri gripped the country.
Another complication is that, as in so many other areas, Texas likes to go it alone when it comes to power. Unlike the rest of the US, most of the state is on an independent power grid with few connections across state lines, so Texans couldn’t import power from other states during Uri. Before the recent cold snap, ERCOT forecasted a 1-in-6 chance of a grid emergency if a big winter storm were to hit the state. (ERCOT declined a request for an interview.)
With no major grid-related outages despite the winter demand peaks last week, it appears Texas power producers, grid operators, and regulators learned and applied the bitter lessons from 2021. Power providers invested in winterizing their infrastructure and ensured enough electricity was available.
Texas set 3 all-time records for power demand & supply this winter storm.
The ERCOT power grid performed flawlessly, never failing.
No Texan lost power b/c of the grid.
This is b/c of reforms that added more power generation, winterized the grid & gave more tools to ERCOT. pic.twitter.com/aoIBbNWD7l
— Greg Abbott (@GregAbbott_TX) January 16, 2024
However, the recent cold didn’t bring as much precipitation as the 2021 cold snap, so icing wasn’t as big of an issue for the power system. And ERCOT still had to ask Texans to conserve power.
Smarter power management can keep us warm
The demand side of the equation, however, could still prove to be a problem. In Texas, 61 percent of homes use electric heating, compared to 39 percent across the US as a whole. That means there is still a lot of room to grow for electric heating, so the task of providing wintertime energy when the temperature suddenly drops could get harder. Meanwhile, more Americans are buying plug-in electric vehicles. Together, these factors will steadily push up electricity usage in the winter across the country.
“Our 2023 forecast shows that the winter peak is expected to grow steadily over the next decade,” said Anne George, spokesperson for ISO New England, the grid operator for much of the northeastern US, in an email.
On the other hand, electrification also creates opportunities to increase reliability. Appliances that can be programmed to take advantage of real-time energy prices or respond to grid alerts can help smooth over peaks and troughs in electricity demand. And batteries in cars and homes could be tapped to push additional electrons onto the grid when supplies are tight. Texas last year began testing virtual power plants, where grid operators can tap household products like Tesla’s Powerwall, a home battery system, to provide electricity. Better insulation and increasing energy efficiency can also slow the overall demand increase.
So, it’s possible to stay toasty without heating up the rest of the planet. It just requires careful planning and flexibility, aimed not just at the highest peaks of energy use during the year, but at rising demand overall.