The OP is taking it all in.Only $250,000 to get the grid to us. And that was 10 years ago. In comparison, solar and generators are cheap. But if you have power poles around this doesn't seem to be much of a discussion to me.
BTW, has the OP responded? Bwah-hah.
I have even found a good used 15kw Generac portable generator.
But the above comments about a suitable generator, even though the math works, the welder might not.
I might need to ask another electrician.