One more point I forgot to mention is that running a spark ignition engine on either propane or natural gas allows greatly reduced wear. Gasoline enters the cylinder as a liquid (some of it anyway) which washes most of the oil film off the cylinder walls, and some of it ends up in the crankcase where it adulterates the oil. Especially true when starting up and choked. Gaseous fuels do not do this, and the oil doesn’t break down as quickly, and stays clean for much longer than with gasoline operation. Probably not an issue on a rarely used machine though.
To me, and to people around here who take this issue seriously, it isn’t a question.
I am not an expert, but I know several people who have been providing themselves with emergency/backup/off the grid (as in camps) power for decades. Propane/natural gas is the only realistic option.
The reason is simple: reliability. A gasoline powered generator, when infrequently used, gums up. A propane unit stays much cleaner and much more likely to start when you need it. Remember you will be running the unit every month for testing. And hopefully you won’t need it very often. Backup power units are expensive and take work-simply because they run so infrequently that the maintenance is difficult to keep up with.
Now, if you are going to get a generator for a single operation-say a hurricane is coming, then gasoline is a cheap option and one I would go with. But realize that it has a relatively high failure probability and high maintenance costs later on.
It seems like the responses here mirror what I’ve found others to say in real life. That is, it seems the more survivalist types say go with propane or natural gas, due to the relatively lower maintenance, lack of lines fouling, bad gas, cost of fuel, etc. The exception is a coworker who was pretty insistent on gas, because (as I mentioned earlier) he claimed to have personal experience with a propane filling station being down due to lack of power, whereas gas stations are more likely (or there is more likely a chance to find one) with power. The way I figure it - it’s a crap-shoot. It all depends on where the tree(s) fall.
On the other hand, when you want quick and simple and more limited use, gasoline is preferred because the options available are greater, and using gasoline is just a default fuel source for many people.
Aceplace57 - I didn’t realize those grill tanks power a generator for that long, either. The genny I’ve been looking at says it’ll run at 50% load for 10 hours on a 20# tank. It was the realization that those tanks can be used that grabbed my interest in propane.
Kevbo - I had heard that NG or propane induces less wear on the internals of an engine, but never really looked into why. Your explanation makes perfect sense - thanks for providing that information.
LSLguy - regarding failure of NG - I figure if that fails where I live (eastern MA), then it has probably failed due to an earthquake, and if an earthquake came through here that broke the line(s), then we probably have bigger issues. Of course there is the freak accident of a NG line being broken during a roadwork or whatever - but unless they are digging up the sewer line in the middle of an ice storm or blizzard or hurricane, I’m not concerned about that. But you do raise the point about their ability to pump the gas in an extended outtage. Not knowing exactly how the gas makes it to my house (I know it likely comes from the TN gas line, and there are compressor stations along the way - but I dont know where the closest one is, nor do I know how reduced the flow of NG would be if it were unpowered), there is potentially some vulnerability there. However, maybe those compressors are run via electricity produced from tapping directly into the line itself? In other words, since NG is very widely used for heat in this region, maybe the failsafes for delivering the gas are such that each pumping station is essentially fully self sufficient.
The thing that eases my mind on propane, and its availability is the number of places I pass and that are near me that refill propane:
- hardware store on the way to work
- blue rhino dropoffs at a few gas stations
- BJ’s
- propane processing plant the next town over for commercial/residential propane deliveries
- neighbors. I figure in an extended outtage, they’ll be looking for gas, and will have less issue letting me borrow their grill tank
One other concern I had is rain.
I plan on storing my generator in my shed. Then taking it out to use. Do I need to rig a cover over it? Would an occasional rain soaking hurt it?
I never mow my lawn in the rain. 
So this issue hasn’t come up before.
As stated above, gasoline goes bad unless treated or exchanged often. Odds are, when you really need it, it will be gummed up and “no start”. Plenty of gas stations??? If you have no power, why do you think they would have power to run the pumps/register?
Go with the propane or NG option. Have spare tanks or a single larger one.
Personally, a 15/20 year event; don’t bother. Put that $10/$15 a month into your Xmas fund. Talk your neighbors into buying a whole house unit; concentrate on insulating your pipes.
Regarding the availability of NG, last February we had a freeze event the the El Paso area that took out most of the local power generation capacity. By most standards it wasn’t unusual (4 days straight below freezing) but for the area it really was unprecedented. Power plants were designed to withstand peak loads on 115 degree days, not 15 degree days. Anyway, the natural gas supply in the region experienced low pressures due to the lack of electricity for pumping operations. It didn’t happen, but we almost lost natural gas service that week. Perhaps it was an anomaly here, but if the gas utility relies on the power utility, then it’s not a secure source.
LP is expensive as hell, but a 250 or 500 gallon tank isn’t an unreasonable thing to have around if you use LP.
Can you really mean this?
Many of us use electricity to get water from wells. Having no water or refrigeration makes living a great deal more work. Plus, we had to shell out a couple hundred dollars to replace food we lost during Irene. During Isabelle, we had no power for 11 days. I am not sure how long it would take our pipes to freeze, but could imagine several bad days of ice storm could push us over that edge.
It’s hardly about X-boxes (though I admit I am a little hazy about exactly what one does).
No love for diesel? IIRC Diesel is much more stable than gasoline. Of course many diesel generators are for bigger buidings than houses.
Brian
I have a 14kwnatural gas unit that powers the whole house, and the neighbors if they have a long extension cord!
NG is the lowest maintenance, easy-starting, don’t-have-to-go-out-in-the-rain/snow/storm/cold to re-fuel.
That said, just in case the NG pipeline dries up after a few days, I can easily switch it to LP, and have a big LP tank in the shed that will last weeks.
If aliens take my LP tank, or it’s empty, I have a portable gas generator that I can plug into the transfer switch. I just pull the NG plug, and hook up the gas plug.
I have instructions written, laminated, and taped to the transfer switch so even [del]a woman[/del] my wife or kids can do it if I’m not there. 
Natural gas is the way to go if money is no object.
I just bought an 800w two cycle generator from Harbor Freight. Yes 800w is very small but I only need it to run the heat in the winter time. Plus our power has been very reliable.
Why get a generator if our power is very reliable? Because, it was only $90.
I couldn’t see spending $300-500 for a generator we’ll probably never use but for $90 I’ll take a chance.
Word.
Note that if you do not disconnect the main prior to connecting and running your generaator, the poor bastard up the pole on the steet fixing the line will be zapped if he or she forgets to check if the supposed dead wire is live due to your sending juice into it via your generator.
Wat back in 1990, after a big windstorm out here in Seattle (known ever after as the "Innagural day Storm), our power was out for three days. I went out and bought a 3300 watt Honda soundproof (sort of) generator, and had an electrician hard wire it up to the house via a transfer switch. The generator runs on gasoline, and is started by a remote switch in the house.
One of the best things I’ve ever done. The power doesn’t go out very much now, maybe once a year, but when it does go out the generator is definitely worth it. And it makes you a hero to your wife, too (one of the real fringe benefits). The 3300 watts has proven to be plenty for normal use - just don’t try to run the microwave, the toaster, and the electric coffeemaker at the same time. Doesn’t do any damage, but you’ve got to go start the generator again after turning off the loads. And it is great when the power goes out at night and you are the ONLY house in sight with lights burning merrily and the TV playing.
Running it on gasoline hasn’t been a problem, but I do start the generator and run it for a half hour or so every three weeks to a month. Propane or NG would be more convenient, but not enough, at lest in my situation, to warrant the extra cost. And I would advise being very careful with having a propane conversion installed on a gas generator. I have direct knowledge of several instances where this has not resulted in a satisfactory situation. In one case, a neighbor of mine had this done, and had much trouble starting the generator, even after several trips to the repair shop. The supplier stalled him off for the year that the warranty was in effect, and he (the owner) ended up buying another generator and throwing away the old one. The new gen. is gasoline, and gives no trouble. Not saying that a propane conversion won’t necessarily work, but make sure that the supplier stands behind it.
Sorry, I meant innaugural. I HATE (obviously) proofreading!