117 years, but only as long as we completely ignore that all the batteries have to be replaced every 5 years, the solar cells every 20 years, and the diesel gen

117 years, but only as long as we completely ignore that all the batteries have to be replaced every 5 years, the solar cells every 20 years, and the diesel generators have to be continually maintained and swapped out with new fuel - if you just store diesel passively long term, even with fuel stabilizers, it goes bad, so use it or lose it with that.