Is It Cheaper to Run a Generator on Propane or Gas?

row of red propane and gas tanks

The Benefits of Propane

Around the rural areas of Weatherford, Texas area, many homes and businesses are powered by propane tanks, and propane delivery service by truck is commonplace. Propane gas provides a source of power for many things, like our outdoor grills, and campers. For those uses, we can purchase small portable propane tanks at a local store. 

Another use of propane is for a power generator. Is a propane generator worth it? Power generators are not inexpensive, but they can make a difference when you live in areas where hurricanes and tornados are commonplace. A power generator can be essential for providing electricity for lights and the refrigerator, sometimes for days.  

Most generators in these cases are portable and use gasoline to power them. However, there are generators equipped and connect to a natural gas or propane gas tank. Homes in rural areas that have propane delivery services will typically have their generator set up to run from that same tank as the rest of the house. In homes that are powered with natural gas, the gas lines are buried underground.

How long will a generator run on propane?

The length of time a power generator will operate will depend on two factors: 

  • The size of the generator
  • The load it is supporting

An example based on 20kw of power load, a propane generator could up to three gallons of propane per hour. So, if you have a propane delivery fill a 500-gallon tank, which will only have 400 gallons delivered, you could have seven days use of running on a propane generator. 

You’re probably thinking “Wait a minute, why do you only get 400 gallons of propane delivery for a 500-gallon tank?!”.  Propane expands as much as 17 times, so to maintain the standard propane safety rule of 80/20, the propane delivery driver will deliver a maximum of 400 gallons. 

What is the most efficient propane generator?

A propane generator will provide convenience in the situation of a power outage, but efficiency does matter. In a power outage, you don’t need to worry about having propane delivery too, and you want to be as environmentally friendly as possible. 

Like anything else you purchase, there are better generators and then there are some that aren’t worth having. The following are six of the most popular choices in propane generators:

  1. Champion Power Equipment 200961 2500-Watt Dual Fuel Propane Generator: While it can be loud when running a heavy load, you can get 34 hours’ use from a propane delivery, or 11 hours on gasoline. 
  1. DuroMax XP10000EH Dual Fuel Portable Propane Generator: Runs on 140 or 240, with propane delivery you can get up to 8 hours of use. Also runs on gasoline.
  1. Westinghouse Outdoor Power Equipment WGen3600DF Dual Fuel Propane Generator: Twenty pounds of propane will give you up to 8 hours of service. 
  1. DuroMax XP4850EH Generator-4850-Watt Dual Fuel Propane Generator: Available with equipment to soften the noise level, you’ll get up to 10 hours from a gasoline-filled tank or propane delivery. 
  1. Champion Power Equipment 200914 4250-Watt Dual Fuel Propane Generator: Provides up to 22 hours on a tank of gasoline or propane.
  1. A-iPower SUA2000iD 2000-Watt Portable Inverter Generator Gas & Propane Powered: A low decibel level of 55 and runs on both gasoline or propane for approximately 7 hours depending on the load.

How long will a 100 lb propane tank run a generator?

A 100-pound tank of propane delivery can power a 7-kilowatt generator for up to 65 hours or power a 12-kilowatt generator for up to 35 hours. How long a propane tank lasts depends on the load they are supporting. 

The “load” is a reference to how much stuff is being powered by the propane delivery. 100-pound propane delivery is approximately 23 gallons. A propane-powered generator operates between 25% and 75% of capacity, it is possible the fuel supply could last longer, again, depending on the load it is supporting. 

Does natural gas burn slower than propane?

While a propane delivery will cost you more upfront, you’ll get more bang for your buck than you will with natural gas. Natural gas burns at a rate of 2:1, meaning you use two times the amount of natural gas as you will with propane gas. 

Can natural gas be stored in a tank?

Propane delivery arrives in a liquefied petroleum gas form that is compressed before delivery. It is colorless and odorless, like natural gas, and has a mercaptan added to give it that rotten egg odor for safety.  Natural gas must be at room temperature and under 32,000 kPa of pressure. Therefore, it cannot be stored due to the molecule and symmetry of its existence.

view from above of a propane tank

At The End Of The Day – Cost Matters

So, while we know that propane delivery is going to be more expensive than having natural gas running to your home, what is a good price for propane? Like the gasoline used in your car, the price fluctuates daily and can be cheaper in some areas, approximately $3/per gallon and as much as $5/per gallon.  

What month is the cheapest for propane? The early part of fall is a good time to have your propane delivery for refilling the household tank. The weather in Texas is stable most years, although that early cold snap could happen.