Recently I was asked the following question by someone who wants to install a 5000-watt generator to run their home in case of a power failure:
What is the best choice for fuel, propane, gasoline or diesel?
This reader is leaning towards getting a propane-powered generator. The choices are confusing, and a guide like this one can help the newcomer to the world of generators make the best choice.
I have been doing some research on the subject and here are some of the advantages and disadvantages of all three fuels for generators: gasoline, diesel, and propane.
|Propane:**See propane notes below.||
Propane produces 92,000 BTU’s per gallon, gasoline is capable of producing 114,000 BTU’s per gallon, and diesel is capable of producing 129,500 BTU’s per gallon. This means that it will take more propane per hour that either gasoline or diesel to run a generator.
How much propane will my generator burn per hour?
- It requires 2 horsepower to produce 1000 watts of energy per hour under load
- Under load each horsepower consumes 10000 BTU per hour
- Propane contains 92,000 BTU per gallon
- Propane weights 4.2 pounds per gallon
Using these factors how long can a 5000-watt generator run on a 500 gallon propane tank at 50 capacity.
- 10 horse power at 50% would use 5 HP to generate 2500 watts of electricity
- 5HP X 10,000 BTU would consume 50,000 BTU per hour
- 500 gallons X 92,000 = 46,000,000 BTU of energy in a full 500 gallon tank
- 46,000,000 BTU divided by 50,000 BTU = 920
- A 500-gallon tank that is full would run a 500-watt generator at ½ capacity for 920 hours.
After comparing the various fuels, I would probably go with propane for a large generator in a fixed setting. I would want a minimum of a 1000 gallon tank. For small generators I would go with a tri-fuel generator. Tri-fuel generators burn propane, gasoline and natural gas.
If you choose to purchase a large generator you need to weight the cost versus the benefits. Is running a generator worth the cost? Another consideration is how much fuel you are able to store. Propane tanks store indefinitely, which is another reason the propane generator is a good choice.