How can the Southern power grid handle months of blistering heat with everyone blasting air conditioners, but can’t handle two days below freezing?
In: 1150
In general, in extremely cold times like there, there is a much larger temperature difference between the inside and outside of a home compared to warm summer days, so more work has to be done to maintain that difference.
Heat pumps (where gas furnaces are not used as a primary heat source) also tend to be less efficient at very low temperatures. As a result, performance may be inadequate and electrical heat will be used as a backup, which is even less efficient.
At my parents home in the middle of Alabama right now, their gas furnace at nearly an 80% duty cycle can barely maintain a internal temperature in the mid 60s, and so they’re also using space heaters in a bedroom for comfort.
In addition to what these people said, this particular storm has a severe wind that came with the dropping temperatures. In many parts of the south, power lines are not buried for many reasons. Severe wind by itself can take down trees, but add that to freezing cold weather and you get trees that snap easily and fall on equipment and wires.
The issue isn’t power demand but the durability of the grid itself. The various production/distribution mechanisms aren’t built to withstand temperatures that low and the maintenance/repair systems aren’t designed with those temperatures in mind.
It’s also more than just the power systems. Consider the road systems. In the Northern states, you’ll have electrical workers out in even extreme situations because they’ve got the personnel, vehicles and training to deal with that weather – and there will be snow/ice-clearing progress on the roads for the same reason. In the Southern states, those personnel and their equipment would need to be imported from elsewhere.
If you’re using electricity to heat your house the amount of electricity you need to bring into your house is directly proportional to the difference between indoor and outdoor temps. Because heat loss is directly proportional to the temperature difference.
On a ridiculously hot day the difference between inside and outside is somewhere around 30 degrees for most of the region. Often closer to 20 degrees.
Right now across most of Texas, for example, that difference is closer to 50 degrees. In other parts of the South it’s 60+ degrees.
So you’re losing heat twice as fast on a day like this as you’re gaining it on almost any summer day. So best case are using 2x-3x as much power.
But it actually gets worse than that – in this region heat pumps are a popular heating choice as they’re an efficient and economical way to provide heating in most winters. The thing is heat pump efficiency goes down once you’re below freezing, and gets worse the further below freezing you get, so you need to use even more power to overcome the inefficiency you’re getting hit with. So some places might be using 4x as much power to warm their house right now than they would on all but the hottest summer day.
Trees. We’re not used to cold temperatures and snow storms in the south, so we don’t trim trees near power lines as well as people up north. You get a little snow or rain that freezes on trees and they crack like grandpa’s back when he gets out of the la-z-boy. These broken limbs can fall on power lines and boom— no power.
Also, it’s still windy and cherry picker trucks can’t operate their boom in high winds. So it’ll take time to fix the problem.
Us – and our homes – are more accustomed/equipped for the heat. When the cold comes, we bring out an army of space heaters. Space heaters are pretty much the least efficient electrical thing on the market, and that load goes all the way to the grid.
(In addition to the other answers. All are valid – there’s a lot of things going on when it hits 8° in the south)
If we’re talking about Texas particularly, a huge part of the problem is that utilities haven’t invested in winterizing their plants. If you take a look at what happened during the freeze last February, a huge amount of natural gas capacity was offline because it was too cold for the plants to operate.
Modern heat pumps are perfectly capable of operating at subzero temperatures. They’re a bit less efficient, but are plenty to keep a reasonably insulated house warm.
[removed]
I’ve experienced more issues with the power grid on really hot summer days than I have with cold days.
Specifically for Texas:
We have plenty of generation capacity. It’s not simply that we get too much load. It’s that our power plants freeze up and go offline. If a large percentage of your power plants fail AND your load is high, then that’s the problem.
Why does cold break power plants? Mostly because there is a lot of water involved. Steam generation, cooling lines, etc. Back in Feb 2021, that storm also combined rain with freezing temperatures. This coated everything with a thick layer of ice, collapsing trees, power lines, etc. This ice coating was also a problem for wind turbines, and Texas has a lot of those.
Why aren’t power plants built to handle this kind of cold? Because it’s so rare. It “never” freezes here… until it does. This kind of problem has significantly disrupted the Texas power grid to the point of shortages and rolling blackouts 3 times since 1970. This killed a lot of people in Texas in 2021, so now there is a lot of pressure to be better able to handle these situations. Rare property damage wasn’t such a huge deal, but rare killing a bunch of people is a problem.
To give you an idea of how things are built different here because freezing isn’t considered a concern… All the houses in my parents’ neighborhood have the water supply entering the house as raw copper lines running outside the house. No insulation, not underground, and nothing to protect them at all. Just copper out in the air mounted outside the exterior wall. Imagine the same thinking at power plants.
Latest Answers