A reader recently emailed me and asked about choosing a generator. She in particular wanted to understand the differences in fuel types. So I thought instead of just sending her a reply directly I’d post my response here so everyone benefits!
The broad answer is that there are two main things to consider when choosing a generator. What type of fuel does it use and how much power does it generate.
How much power does my generator need to provide?
I touched on this a bit in my emergency power post but I’ll go over it here briefly. The basic thing you need to do is figure out what you want to provide power for in an emergency, do the math on the overall wattage needed, add a buffer, and there’s your number.
Realistically, if you go get a a7-8kW generator you’re going to be just fine for almost all of your needs. But by all means do the math!
Rudy’s Tip: Generators have two power ratings … peak and sustained. You need to buy based on sustained load. Peak load is basically power that the generator can deliver for a short period of time as needed. Generally speaking this happens if you turn on a major appliance, etc. Be a careful shopper!
You can ballpark the burst load for most appliances by simply doubling the wattage of the appliance.
What about fuel?
There are three major types of fuel for generators: Gasoline, Diesel, and Propane.
Gasoline has some advantages. It’s easier to come by than diesel or propane. It’s cheaper than both in many places, though that’s not always the case. Gas powered generators are usually cheaper as well.
On the flip side, gas powered generators operate at a higher RPM speed, which decreases the usable life of the generator. Gasoline is rather volitile and is pretty darn flammable. And it has a pretty limited shelf life. Think six months to a year untreated, though you can get two years if you use an additive.
Diesel has some advantages as well! It’s relatively common. For generator use you can get farm diesel which is usually much cheaper. Diesel engines run at a lower RPM speed and last a long time. Diesel is also far less flammable than gasoline and it stores for years, even longer when treated with an additive.
On the down side, diesel generators are more expensive, sometimes significantly so. They can be harder to find as well.
Propane is often easy to come by since lots of people use it for their grills. The major downside to propane is that it is highly flammable. On the flip side, it stores forever. Price wise, propane generators are about on par with diesel generators, but can be a bit harder to find.
Rudy, what would you do?
It’s a very personal choice and depends on your circumstances. Here are my personal thought processes on it:
I see no reason to NOT have a gasoline generator or two around. They’re inexpensive (you can get a high output generator for a few hundred dollars) and very versatile. Throw one in the back of the truck and you’ve got a great mobile power source.
I like both propane and diesel. For me, we have diesel available already and use it for heavy equipment as well as other vehicles. We don’t intend to use propane for heating our home when we build it. So as a result, diesel is the obvious choice for us.
If we had propane heat, I’d seriously consider buying a propane generator. It’s very viable, and I don’t have anything really bad to say about it!
If you want advice on your specific situation, please feel free to email me at firstname.lastname@example.org and I’ll be happy to give you some one on one advice!