Comment: Perspective from developing country (Score 1) 337
2-3 hours of power outage a day is common in many cities. In summers 10-12 hours is also common. So most commercial establishments have a diesel Genset with 24-48 hours of diesel stock. Our apartment building keeps around 3-4 days of diesel in stock. Many commercial areas get 8 hour long cuts every day in summer as there is not enough power to go around, so there are these big diesel gensets and usually fuel enough for running 15 days is kept. I remember, once the power substation went down. For 72 hours there was no power, and diesel genset kept running.
People who live in independent homes usually have a inverter which gives 1KVA for around 10 hours max. In areas where power cuts are more common, homes have a 5KVA diesel genset which can run the fridge and one air conditioner.
So I guess, due to inherent shortage, and due to the fact that even 20 hours of power a day is not guaranteed, homes and apartments are much better prepared.
That said, in some regions where power is surplus (low population, and hydro power plant in "backyard"), diesel gensets or inverters are rare. So after a winter or a summer storm, when trees snap power lines, power can be out for as long as 24 hours. Happens quite frequenty in Himalayan region after heavy snow fall or during monsoons, when landslides and mudslides can uproot trees and snap power lines.