Since a continuous supply of electricity is what most customers demand, utilities have systems in place that practically eliminate the possibility of service outages. Regular trimming and clearing of trees around overhead lines, infra-red scanning and routine preventive maintenance are just a few of the ways to protect and improve your service reliability. Unfortunately, there are circumstances beyond your utility's control. Situations like severe weather, accidents involving electric lines, equipment failure, and vandalism can cause power disturbances. When longer outages or permanent faults occur on the primary circuits serving an area, all power is interrupted until the cause of the fault can be isolated and corrected.
Diesel generators are designed to be resistant to this sort of power failure. Power failures are particularly dangerous for hospitals, since many life-critical medical devices and tasks require power. For this reason hospitals, just like many enterprises, have emergency diesel generators which are typically powered by diesel fuel and configured to start automatically, as soon as a power failure occurs.
Retail businesses that sell fresh or frozen food that rely on constant refrigeration are another example of the need for emergency power. Many seafood-related businesses closed down permanently after Hurricane Ike, since most of their inventory perished due to multiple days without power.
Consider how important/critical electricity is in your home or business. How long can you survive without power? If there is a situation that causes concern for you, do your homework to determine if a generator is appropriate for you.