Propane vs Gas Generator — what’s the difference? Which portable generator fuel type is right for you? We all have different needs, especially when it comes to generators. Choosing between either a gas or propane generator really depends on what you intend to use it for. In this article we provide you with a framework to help you make the correct decision.
If you live in an area where hurricanes are likely and probable then I recommend a dual-fuel generator. When fuel is scarce you’ll want the option to get from power from either gas or propane. Propane will last indefinitely (won’t expire or go bad) while gasoline can only last for about a year (with fuel stabilizers). It’s good to have options when a disaster strikes. Think ahead.
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Propane vs Gas Generator
Any generator needs fuel to run. Traditionally, this has always been gas or diesel. However, in recent years, propane or Liquefied Petroleum Gas (LPG) has become increasingly popular as a fuel used to power generators. Propane has very similar combustible qualities to normal gasoline and will use the same carburetor. This makes it possible to use either fuel for the same generator, provided the generator has been designed for both fuel types. Generators that are able to use either gas or propane are known as dual-fuel generators.
There seems to be a big debate as to which is better, propane or gas. This article is going to unpack these issues. In a sense, the propane vs gas generator decision might be more of a personal choice. There is very little that distinguishes the actual capabilities of the generator. One notable difference is that a generator that uses propane won’t have the same wattage capabilities as a gas-powered generator that has the same engine. One can typically expect to get around 10 – 15 % less power from a propane generator compared an equivalent gas generator.
Despite the lower power output, propane generators are very popular. Much of this has to do with an increasing environmental awareness. Propane, when compared to any other fossil fuel, burns much cleaner. The fact that propane produces lower levels of harmful emissions has resulted in it being favored among the green-minded people of the world. That’s a good thing and, even though they don’t know it, the polar bears can be very grateful to those who choose to use propane over gas.
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There are other reasons why some prefer propane vs gas for their generators. I think the biggest practical advantage to propane is the manner in which it is stored. Gas, stored in cans, always emits fumes which are both unpleasant to smell and can be quite hazardous. Gas fumes are flammable and one always has to be aware of this when storing and transporting gas for your generator. Propane, on the other hand, is stored in completely sealed tanks. There are no unpleasant, potentially dangerous fumes to contend with. There’s no chance of spillage when transporting and you connect a pipe from the tank directly to your generator.
Unlike gas, that needs to be transferred from a can to the generator’s tank, propane is used directly from the storage vessel. I suppose the only downside to propane tanks is that they are heavier than gas cans. Propane tanks need to meet specific safety regulations due the high pressure under which the propane is compressed into the tank. This means a thicker grade steel needs to be used.
Availability and price can be an issue. Generally, gas is much easier to obtain. In some areas, propane is not widely available. As far as the cost goes, it really depends on the vendor and, perhaps local restrictions in supply. In some cases, propane can be cheaper, but gas is often the more affordable option. One, less obvious, aspect to availability will be in times of natural disaster. This is something we may not realize until it becomes and emergency.
Sportsman GEN4000LP | Runs on Propane
During a hurricane, snow storm, or earthquake, supplies become limited. The effect of these conditions on roads and other infrastructure means that days, sometimes weeks, can go by before it’s possible for supply trucks to reach the affected area. It’s at times like these, when we most depend on our generators, that gas may be difficult, even impossible to get. People fill up their cars and stash emergency gas supplies the moment disaster strikes. Since propane isn’t as widely used, it might more available when gas supplies run low. You just need to look at long line of vehicles at gas stations during a hurricane to appreciate this.
There are other advantages to using a propane generator during times of natural disaster. Propane has an unlimited shelf life. You can store it months in advance, allowing you to prepare more in advance for a hurricane or snow storm. Gas containing ethanol, which is most of the gas we get these days, is said to only be usable within a month. This makes long term gas storage less viable. Since you probably use propane for other purposes, like a barbecue, stove, or heater, it is much more practical to store larger amounts of propane that can be used for all your fuel needs.
A propane generator is less hassle to store. If you store a gas generator, you need to drain the carburetor of fuel to prevent it from becoming clogged with the residue that remains after the gas has evaporated. You also have to empty the gas tank or add a fuel stabilizer. Propane does not leave any residue in your carburetor or carbon on the spark plug. So storage and general maintenance of a propane generator is less hassle. Generally, propane engines last longer and cost less to maintain. So there are long term benefits to using a propane generator vs gas.
So far, it seems like the propane vs gas generator race has propane winning by a long shot. But there is more to the story and propane has its disadvantages. I’ve already mentioned the lower power output aspect to using propane. While the difference in wattage between a propane generator vs the same gas-powered engine isn’t too great, it can make a difference.
While propane is quite a safe fuel source, you can’t see it. This makes it difficult to detect when there is a leakage. Sure, propane manufacturers are required to add a distinctive scent that allows us to smell when it is in the atmosphere. But propane is heavier than air and will always sink to the lowest point. You may only smell leaked propane when it is too late. If a propane tank is used or stored close to a drain, it can be particularly dangerous. The propane will drop away into the drain, filling the drain pipe with volatile combustible gas. This has been the cause of most propane related explosions. If you’re using propane, you need to be constantly aware of this invisible danger. You need to inspect your propane tank, pipes, clamps, and fittings regularly to ensure that they remain safe.
If you use your generator in freezing weather, propane can be problematic. It is stored in a liquefied state and is converted to gas as the pressure is released when it leaves the tank. This conversion from liquid to gas requires a heat transfer. Heat from the surrounding air is used in the conversion process. Granted, the air has to be extremely cold before this can be a real issue. But it can become a problem. A more realistic problem when using propane in ambient temperatures below 30 degrees is the tendency of the regulator to freeze up. The pressure inside the tank is much too high for regular use. So a propane generator, like a stove or heater, uses a regulator to control the pressure. When this freezes, your generator is rendered unusable.
Once we consider all the angles, the question regarding gas vs propane generators has no obvious conclusion. Both have their pros and cons. Gas may be in short supply in times of natural disaster and is not as practical to store, especially for longer periods of time. I guess this gives propane the advantage for doomsday preppers. But most people who rely on their generator for emergency backup power will appreciate these considerations. Propane has its unique safety concerns but, then again, so does gas.
Perhaps the best solution is a dual-fuel generator that uses both propane and gas. Having more options can be a huge benefit during a hurricane or snow storm. Versatility in the type of fuel that you can use, means you have more options and that’s always a good thing.
Cost to Operate : Gas or Propane?
Here’s a question we recently received from Robert, one of our readers, which I feel is worth sharing with all of our readers, since I think it’s a fairly common question.
“Is it cheaper to run gas or propane on a dual fuel generator? Figuring cost of fuel, runtime you get, etc. I know propane is “less efficient”, but as a consumer I only care about cost. I was trying to compare gallon to gallon but that isn’t quite the same run time.?
The only true way to compare running cost figures for a generator is by calculating your cost per kilowatt-hour ($/KWH). Because prices are not the same everywhere, I’ve calculated the cost of gas vs propane for a Champion 76533 (3,800W) generator, using average US prices.
This generator is reasonably fuel efficient, but the ratio between propane and gas consumption rates are roughly the same for all dual fuel generators. So, it makes for a good basic comparison when it comes to fuel cost. Propane prices in the US range from $12 – $18 for 20 LBS (average $15). Gas prices range from $2.13 – $3.29 (average $2.50). Based in these average prices, running costs are as follows:
- Gas: $0.47/KWH
- Propane: $0.83/KWH.
You’re spending (on average) 8.50 to fill the gas tank for the Champion 76533 and you’re getting 9-hours @ 50% rated load.
You’re spending (on average) $15.00 to refill a 20LBS propane tank and you’re getting 10.5-hours @ 50% load.
If we compare the cheapest propane price ($12.00) to the most expensive gas price ($3.29), the cost to fill the same gas tank would be $11.19 vs $12.00 for propane. Gas still works out to be a little cheaper: $0.65/KWH vs $0,67/KWH for propane. While gas will always cost less, the difference may not be too much. That would depend on your local prices for gas vs propane.
In some cases, propane can cost twice as much per kilowatt-hour of power generated.