Back-up systems for when the power goes out

Power outages are rare and usually short here, but grid-provided electricity isn’t completely consistent and reliable under all circumstances. Here’s a quick guide to the world of power quality problems and actions individuals and businesses can take to minimize negative effects.

Transient power quality issues that don’t result in outages include voltage variations (sags, swells and spikes), poor current frequency and problems with power factor. (Power factor is technically complex and is usually only relevant to businesses that use many electrical motors.) These problems only last for milliseconds to minutes. Most of the time, individuals and businesses won’t even notice them. Sometimes, fuses will blow, circuit breakers will trip and, sometimes, sensitive equipment can be damaged.

If you are in a situation in which better management of transient power issues is desirable – for instance, if you’re concerned about your electronics – you can install equipment to protect your equipment.

Sensitive electronics can be protected from unexpected high voltage by plugging them via a surge-suppressing power strip. These strips need to be replaced every few years, so read their specifications and put a date label on them and replace periodically to maintain protection.

If equipment might be damaged, or might cause damage, by suddenly shutting down, or by going on and off due to transient voltage variations, it can be protected by plugging it in via a backup battery that will keep the equipment on and allow you to shut it down in an orderly manner. This includes computers and industrial machinery like plastic film extruders, which can require hours to clean up and restart after even the briefest power interruption.

Outages that last more than a few minutes can be caused by physical damage to the grid due to, e.g., squirrels or cars. The occasional grid management issues, which typically occur during extreme weather when demand is high for prolonged periods. Outages are usually resolved within two to four hours, but can (rarely) last a few days.

Outages of a few minutes or hours can be mitigated by using backup batteries on particularly sensitive or important equipment. Often, a retail electric customer with backup batteries on a few lamps, a television, a computer and an internet connection will not be affected.

Outages long enough to affect refrigerated food, or to substantially reduce comfort because the heating and cooling systems are off, can be addressed with whole-building backup power. On-site generators and storage systems, whether based on solar panels or fueled generators, extend the time homes and businesses can be without power to several days.

People in remote locations, or near the end of the power grid, may want to investigate backup generators, whole-house batteries or electric vehicle-to-grid systems. These systems are for those storing large amounts of food in refrigerators and freezers and/or to businesses like convenience stores, which need to protect their food investment and simultaneously maintain an ability to remain open. Ironically, gas stations often cannot pump gas during outages even though they have fuel, because they do not have backup generators to power their pumps.