Rational Preparedness

Gas, Diesel, Propane, What Generator Fuel is Best?

Generators can run on a variety of fuels and some of them are bi-fuel, so they can run on more than one kind of fuel.  I even found a tri-fuel portable generator, in this Amazon search. Each generator fuel type has its own advantages and disadvantages.  There are differences in cost, ease of use, purpose, storage, and operation to consider.  There is no one best fuel type but with this information, you can choose which one (or more) is best for you.



  • Propane is easy to find as it is now sold everywhere.
  • It has a long shelf life. You can store it as long as your container will hold it, which can be several years.
  • Depending on local codes, most anyone can store massive quantities of it on their property and have it delivered by truck. These leaves you prepared, even if utilities are shut down and travel is unavailable.
  • If you want to use it on your RV/bugout vehicle, you already have propane tanks with you.
  • Most propane generators can run with at least one other fuel type.

What is The Best Small Generator For You? 



  • Using propane means some kind of bulk. If you are looking for your generator to be ultra-portable, propane will get in the way of that.
  • Although you can buy it everywhere, it’s not as easy to buy as gasoline.
  • Fewer options for portable propane generators, though there are some.  See The Duromax XP10000EH on Amazon.  It runs on Propane or Gasoline.
  • Non-continuous source of fuel as in Natural Gas.

Portable Generator Sizing: What Size is Right For you?

Natural Gas


  • Continuous fuel source—Fuel is delivered by gas line.
  • Never have to make trips to the store or add fuel to the generator. It just runs, like your stove or your furnace.
  • Cheaper than propane.
  • Most Natural gas generators can also run on Propane, with a conversion.
  • Fuel never goes bad.


  • Fuel cannot be stored. This means you are dependent on a third party to deliver your fuel on a consistent bases.  Gas outages are rare, even in storms, but they do happen.
  • Some people are searching for a portable natural gas generator.  Natural gas is a fuel supply that is is non-portable, so only standby generators can use it.  Though maybe you can prove me wrong on this, in the comments below.
  • Requires plumbing.


Generac 6462 Guardian Series
The Generac 6462 Guardian Series
See it on Amazon
Runs on natural gas or propane.  Generator conversion with a valve.



  • Greatest variety of portable generators available.
  • Highly portable fuel source.
  • Easiest Fuel to find, with a caveat. See Disadvantages
  • Smallest quietest generators run on it.


  • Short shelf life. After three months, it’s time get it used up, though it could last longer. The presence of ethanol in gasoline has ruined its shelf life.     Ethanol attracts water and is not completely soluble in gasoline, so it separates over time.  Keeping your containers full and air tight helps.  An additive might help but some say the additive is already in it.  If you can find gasoline without ethanol, it could be stored for 2-3 years.  Marinas often sell pure unleaded gasoline.
  • Engine Damage. Because of the fuel’s tendency to go bad, it can damage your generator engine.  Draining can help but you can never drain all of the fuel out.  It’s best to run your gasoline generator at least 4 times per year, if using fuel containing ethanol.
  • Limited quantity can be stored. Generally you are limited to 5 gallon cans, in most neighborhoods, though it is possible to buy a large tank and have fuel delivered.

16673_700x700Honda EU 2000i, Gasoline Generator
See it on Amazon



  • Diesel engines have a reputation for being durable and able to run for extended periods of time
  • Diesel is great for high torque applications, which makes single phase generators possible, so your power isn’t split into different circuits that need balanced.


  • Short storage life. Similar to gasoline, diesel fuel utility has been degraded by government regulations.  It begins to break down after just 28 days.  To extend its life:  Keep tanks full and sealed, use a stabilizer, water controller, and a biocide.  Especially use the biocide.  If the tank is full, keeping water out won’t be as big of a deal.
  • Diesel generators often cost more, to get started with than, gasoline generators.

 Generac 6864Generac 6864 Diesel Home Generator
See it on Amazon

So which one is best for you?

If your goal is to have a bit of power in a thunderstorm a gasoline generator might be best.  If you want to keep your refrigerator and freezer running and maybe a sump pump, while having the quietest experience, gasoline generators are a great choice.  Just keep in mind the fuel needs to be changed out.  Keep putting your stored gas in your car and run your generator–you will be fine.

If your goal is to be prepared for a longer term disaster a natural gas or propane generator might be your choice.  There are portable propane generators and many of them are bi-fuel or tri-fuel.  You can store large quantities of propane or have a continuous supply of natural gas.  Both fuel types are popular for standby generators, which can power your whole house, automatically, when the power goes out.

If you want to run a generator for a lot of hours over its lifetime, a diesel generator might be your choice.

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  1. Maria

    I honestly prefer propane generators as it doesn’t emit carbon monoxide. You can operate it inside the house. But I do have to agree, It’s quite bulky.

  2. Cactus Chusk

    Do NOT listen to what Maria is saying. It is NEVER safe to run any type of generator that burns a carbon-based fuel (gas, propane, natural gas) inside the home. People die each year because of mis-conceptions like this. This is dangerous, careless, uninformed information that will get people killed. Again, DO NOT EVER…EVER RUN A GENERATOR…REGARDLESS OF FUEL…INSIDE THE HOME! Unbelievable…

    1. Joe (Post author)

      Thanks for that. I had missed it.


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