You are right if they were trying to reduce load 50%, that's basically impossible for the reasons you mention. They were only trying to get it down 20% and it might have worked if they could have effectively rolled the blackouts. A lot of people have natural gas heat. It doesn't work when the power is out (no ignition, no thermostat, and no fan), but doesn't put a huge load on the electric grid when it is on. For a well insulated house, you are probably running the heat for much less than 50% of the day. We run on average 6-8 hours in the winter. A rolling blackout where power was off for 1 hour, on for 2 would have exceeded their target savings, and shouldn't have affected heating or demand.

> A lot of people have natural gas heat. It doesn't work when the power is out

That doesn’t have to be the case. I have gas heat [0], that works fine when our power is out.

(Not intending to detract from the rest of your point)

[0] a basic Williams wall furnace on a 50 year old thermostat.

How does the thermostat work? I've had the old mercury switch style thermostats before, but those work by completing a circuit, so I assumed they were dependent on power being on.

Googling tells me it’s “a pilot millivolt system”. I guess the downside of this design is that the pilot* is always lit, consuming a certain amount of fuel. Neat old quick start guide for a similar thermostat: http://nebula.wsimg.com/b2bc334b6de3591406ddd01974f01830?Acc...

* pilot is manual piezoelectric; doesn’t require electric power

How does it blow heat around the house?

Not very well, I lived in an apartment with one of those in the hallway, had to set up a fan to blow warm air to the living room or bedrooms or it got way too cold on cold nights. (which fortunately, were rare where I lived). It'd definitely be better than nothing in an extended power failure, but forced air heat is more comfortable

It’s a wall furnace in the center of the apartment, I guess it blows via convection, outward on both sides of the wall.

These heaters are super common in California, and some larger homes have multiple of them. I assume they’re not as efficient as more modern solutions, but they are certainly reliable and low-maintenance.

I don't know about North Texas but I don't think gas furnaces are that common in Houston or Austin.

These type were quite common when natural gas lines were first run to households in Houston:

Dearborn gas heater example just like the one I had:

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...

In The Heights many original homes have a smaller version(s) built into the wall, sometimes a tiny one right there above the bathtub.

After converting to showers sometimes it's right in your face while standing.

Without a full set of built-ins, there were natural gas petcocks in each major room for portables or relocatables like Dearborns.

Propane gas is relatively common, but wither way:

1) Natural gas has been a problem because the moisture in it has been freezing pipes

2) The cold has caused the pressure in propane tanks to drop, impairing their functionality.

None of this might have been a huge problem if Texas didn't keep its power grid almost completely separate from the rest of the country. That has meant they can't easily bring in capacity to cover their own lack. Though even moderate winterization would probably have significantly reduced the problems. It's not like they have to prepare for continuous -10 F.

I don't know what the geographic distribution is, but overall the state is split evenly between between natural gas and electric heat (45% each), with the remainder being misc sources like propane.

I wonder why it is not possible to reduce the max amount of power each house can draw by 50% instead of doing blackouts. In Italy houses have remotely controlled meters, if you change contract and have a different power allowance your meter gets reporgrammed without the need of an operator on site. This would force people to consume less power to avoid automatic detachment, while still not leaving them completely in the cold.

Don't they have any kind of smart meter in Texas? Maybe reprogramming them is a slow operation that cannot be done to almost every meter in a short timespan?

I suspect smart meters are optional / being lazily phased-in. I've been out of the US for a decade, but I know my dad gets a discount on his electricity because he opted-in to a smart meter.

If you gave everyone power 20% of the time though, I don't think the vast majority of people would shift that much load.

The only real power consumption anyone does above usual is plug in their phones. And obviously their heaters run full blast.