most places that aren't residences or retail have building UPS on premises to handle the load transfer to a diesel generator with fuel stabilizers - 1,000 per day for a reduced-load factory. build with redundancy in mind and expect a 5 figure yearly maintenance bill for generators, fuel, plumbing and valve gear, batteries, the UPS controller, and industrial relays and switches. bury a utility bunker a few meters underground and run protected trunk lines where you need the power and have exhaust routed through a concealed chimney - it's not like it belches black smoke or anything.