End result's the same, though-- no electricity = no heat, regardless of natural gas supply. (But, at least in this case, a relatively small generator can provide enough power to get the furnace up and running and heat the house; the electric furnaces and heat pumps that are most common in places like Texas would need something quite a bit beefier to run without grid power).
Even with the valve barely open you have maybe 3 to 5 seconds to get it lit in a normal fashion. Heh mess around too long and you’re in for a big woosh and plenty of singed arm hair.
Some other models (from the same manufacturer as mine) don't have a standing pilot, but either use a battery as the primary ignition source, or use AC power but take batteries as a backup.
Sooo many different systems and many are just not well thought out. Especially in climates where it usually doesn't matter.
Here in Quebec it does matter so the one we have works in all conditions with various levels of manual intervention. We don't even have the one with a battery operated fan but even that exists.
That size is usually big enough to run a blower and control board (and maybe a few other circuits), but it wouldn't come close to powering an electric heating element. But having a gas heater makes it all doable.
That's what we do, anyway.
Besides, at some point, you're just reinvinting an overly complicated combustion heater.
Which I already have, is already hardwired for fuel, and only needs to be plugged in.
That doesn't make the idea bad though. There have been attempts to do this in commercial furnaces before, but the details are hard, and ultimately of questionable value in general. In this particular situation it might be useful, but that is a lot of complexity for something that only makes sense for a week every 10 years.
Plus having a continuous plug-in (natural gas) fuel source is a big advantage over refilling a gasoline generator, which most portable generators are.
You're confusing furnaces and fireplaces.
A fireplace is soemthing that sits in a living space usually with a visible flame behind glass and is designed more for aesthetics than function. They typically run using a millivolt valve for the gas supply, with the voltage generated from a thermopile sitting in the pilot flame. They're often controlled by a regular light switch or a simple two-wire mechanical thermostat.
There's natural gas and propane models, and they'll run so long as you have gas flowing.
I upgraded mine to use an older wifi thermostat, but kept a light switch on a small cable underneath so I could always use it in case of a power outage, and it's come in handy a couple times. [1]
Mine also has a mains-powered blower fan built in (that's the plug on the left), but electrically it's completely separate and controlled by its own thermostat. It turns on when a certain temperature is hit -- usually about 5-10 minutes after the fireplace is on -- and stays on for some time after the flames are off. Obviously the blower doesn't work when there's a power outage but the fireplace still generates a usable amount of heat for the room.
On the other hand, my gas forced-air furnace -- which distributes heated air via ducts around the house -- is, as you describe, entirely useless without electricity. Even if it was running without the main blower fan, it would just be heating up the air sitting in the duct coming out of it. At best it might get some heat into the house via convection but I suspect it would cut out on thermal overload before actually doing anything useful.
The problem is not so much the deliberate rotating blackouts who can get restored after a time, but large groups of people for whom power is out due to some other weather-related outage issue; there are large swaths of them in Houston at least according to the Centerpoint Energy outage map which distinguishes between the two (but does seem to be not the most timely updated data per various people I have talked to whose status has changed during today: http://gis.centerpointenergy.com/outagetracker/ )
For the furnace yes.
The gas fireplace and gas ovens/stoves though probably don't need electricity.
My kitchen has a gas range, the oven uses electical resistance/incandescent ignitors so it won't work without electrical power. The top burners have spark ignitors but of course I can light them with a match.
I'd imagine heaters have batteries for specifically this case. If they don't, it's frankly a miracle if we don't lose anyone, and someone needs to get prosecuted.
One thing the NEC 2020 update allowed is bi-directional power between an EV and its charger, you can set up an EV to provide backup power your house, with a transfer switch and everything.
Radiant heating systems with boilers require electricity for the pump, even if they’re gas fired. Electric resistive heating needs electricity. Forced air heating needs electricity to run the fan. All heating systems require electric power, even if the heat is generated by burning natural gas.
Forced air heat is not great in terms of comfort, but in Texas you already have all the ductwork and the blower motor and so on for AC, so it's simplest just to add a gas burner to that.
I'm curious how they didn't lose heat. Any furnace built in the last 30 years, even gas, has an electronic control board in order to ensure it doesn't accidentally turn on the gas without a functioning pilot light and/or heating element (which would blow up your house).
No electricity = no heat, regardless of natural gas supply.
I've got about a dozen coworkers in Texas, they've all been without power (which means no heat) for two days now. The power comes on long enough to at least warm their houses up to 50ish degrees before dropping back out so they're not completely screwed but I know they're scared.