Having a backup generator for both short- and long-term power outages is an important part of emergency preparedness. In this excerpt from When Disaster Strikes: A Comprehensive Guide to Emergency Planning and Crisis Survival (Chelsea Green, 2011) by Matthew Stein, the basics on how to choose a generator for power outages are covered, along with a guide on whether you need a large, medium or small generator for your purposes. This excerpt is taken from the chapter “About Generators.”
Everyone should have at least one small, backup generator on hand to provide power for short-term emergencies and power outages. Once the fuel supplies run out in a long-term collapse-type scenario, a generator won’t do much good unless you have the capability of making and using bio fuels, but for relatively short-term blackouts (up to a few weeks in duration), having a generator on hand can make a huge difference to your comfort and safety. Most refrigerators won’t run without electricity, and many home central heating systems require at least modest amounts of electric power to run the fans or pumps necessary to keep a home central heating system functioning. A small generator provides enough power to keep a few lights running, power your refrigerator, your central heating system fans and pumps, and keep a computer or TV running.
Choosing a Backup Generator
When shopping around for generators, consider the following questions:
- Is your generator for occasional backup usage or might it be a primary source of energy for long periods of time? Whole-house generators to provide long-term off-grid power will be considerably larger and more expensive than smaller, more portable generators for occasional backup power and multipurpose use, plus they will consume quite a bit of fuel over a surprisingly short period of time (and can be shockingly expensive to operate).
- Will your generator be hard-wired into your home’s electrical system? If so, it should be installed by a qualified electrician to meet electrical codes that require a transfer switch to disconnect your home from the grid whenever the generator is operating (more on this later). Whole-house generators are quite expensive, and may be installed to automatically and seamlessly disconnect your home from the grid, and switch into generator operation, whenever the grid goes down.
- What is the size of the power loads that you wish to run with your generator?
Small, relatively lightweight portable generators, like the Honda EU2000i and the equivalent Generac iX2000 2-kilowatt (kw) generators, commonly found in use on travel trailers and by car-campers across America, are powerful enough to operate a few lights, a refrigerator and a computer, but do not provide enough power and/or voltage to operate electric hot water heaters, electric stoves, or most air-conditioning units.
The plus about having a small portable generator, either instead of, or in addition to, a larger generator is twofold. First, the 2 kw Honda and Honeywell units are very quiet and they can run continuously in the background with little irritation to yourself and your neighbors. Secondly, they are quite economical to operate the low-power appliances that people tend to find most important during a blackout. My 2 kw Honda EU2001 can run at one-quarter of its rated continuous capacity (400 watts) for about nine hours on a single gallon of gas. My 4 kw job site generator is about ten times as loud, and will consume about 4 gallons of gas over the same period when run at 50-percent load (2 kw) and the Honeywell HW7500E generator will consume about 8.5 gallons of gas at 50 percent load (3.75 kw). A quick calculation shows that in order to run this 7.5 kW backup generator for 10 hours a day for a period of two weeks, you would need to store 130 gallons of gasoline, and fill its tank at least 20 times! However, if I ran fewer appliances and circuits, I could provide the same 10 hours a day of backup power to my home using my small quiet 2 kw generator, and it would only consume approximately 16 gallons of gas — a much more affordable and easily stored amount of fuel.
Larger “job site” generators provide more power, typically on the order of 4-10 kw, and usually include both 110 VAC and 220 VAC output plug sockets, but are bulkier and heavier than the small units. Though still considered “portable”, these generators are heavy (on the order of 100-250 lbs) and usually require at least two persons to lift onto a truck bed or hand carry any kind of distance. Some of the more expensive and larger models in this category come equipped with their own towing trailer for easy towing with a pickup truck or SUV.
You can see photos of different backup generator options in the Image Gallery.
Generators in Your Emergency Preparedness Plan: The Right Fit
When purchasing a portable generator in the 5 kw to 15 kw size range, one thing to consider is whether you wish to go for a diesel or gasoline powered unit. Diesel will be much more economical when run for long hours, but has the drawback of having to winterize the fuel for cold weather use, and deal with cold starting issues. Unless it has been conditioned with a winterizing fuel additive, standard diesel fuel starts to crystallize and clog the fuel filter when temperatures hit 15 degrees Fahrenheit, and turns into an unusable gooey gel as temperatures approach zero degrees. Even with winterized fuel, getting your diesel generator to start in frigid temperatures can be a nightmare, so if you live in a cold climate, your backup diesel generator might fail to start during severe winter weather, just when you need it most!
Heavy-duty “whole-house” generators are on the order of 12 kw to 25 kw in size, and are sometimes mounted on a towable trailer, but are usually permanently mounted on a foundation inside either a small out-building or an insulated utility room to contain the noise and keep the generator sheltered from the elements. These large generators usually operate on propane or natural gas, but may come equipped with multi-fuel options. Due to the high volume of fuel consumed by large generators when operated for extended periods of time, you definitely don’t want to be driving back and forth to a gas station to fill 5-gallon containers of gasoline to keep a large-sized generator operating continuously. Most generator installations in this category are either plumbed directly to a natural gas line, a large propane tank, or a large diesel fuel tank.
Matthew Stein is a design engineer, green builder and author of two bestselling books: When Disaster Strikes: A Comprehensive Guide to Emergency Planning and Crisis Survival (Chelsea Green 2011), and When Technology Fails: A Manual for Self-Reliance, Sustainability, and Surviving the Long Emergency (Chelsea Green 2008). Stein is a graduate of the Massachusetts Institute of Technology (MIT) where he majored in Mechanical Engineering. Stein has appeared on numerous radio and television programs and is a repeat guest on Fox News, Lionel, Coast-to-Coast AM, and the Thom Hartmann Show. He is an active mountain climber, serves as a guide and instructor for blind skiers, has written several articles on the subject of sustainable living, and is a guest columnist for the Huffington Post.
This excerpt is reprinted with permission from When Disaster Strikes: A Comprehensive Guide to Emergency Planning and Crisis Survival, published by Chelsea Green, 2011.