I have an old Honda portable generator that runs on gas, but it is about shot. I don't know how old it is for sure, but we ran it during the big flood in 1985 when the power was out for 6 months, lol. Pretty old. I think when it finally gives up the ghost, I want to get one that runs on propane. Maybe 1500 watts and fixed in place, plumbed into the tanks on the house. I would think that would be enough to run the arc welder if I ever get to a point where I can have the grid power disconnected.

I don't know much about stirling engines, except that they are cool. :P I don't think they are very torquey, though, and might not be able to turn a generator very well once it had a load on it, I dunno.... But I don't know much about them, so I am probably wrong!

I read an article somewhere a few years ago... But I can't find it now. But it was about a student whose family lived in a remote part of Sweden. He made a thing for them to generate a little power on their wood stove by using thermocouples, with a heatsink and a self-powered fan on one side. Apparently the self-powered fan made it a lot more efficient. I mean, it wasn't enough to run a power drill or anything, but apparently they could use it to charge phones and such.

I would think something like that would be really reliable, though, with the only moving parts being a little DC computer-type fan. I have always thought about trying to buy a stack of those thermocouples from some surplus place or other and trying to do something like that with them.