What Fuel does a Generator Run On?

One thing that makes a standby generator great is the fact it is connected into a fuel supply so that the power is uninterrupted. There are three common fuel types: natural gas, diesel, and liquid propane. The following is a breakdown of the fuel types for standby generator use:

Natural Gas

Natural gas has its advantages when it comes to generators. For instance, the generator can be tapped into your natural gas supply so that you do not have to worry about refueling. It burns clean, it has great availability during a power outage, the engine noise level is lower, and the missions are lower. The generator units also tend to be more budget priced.

The only downfalls are that natural gas may not be available during a natural disaster, the installation cost may be a little higher due to the needed fuel system plumbing, and the lifespan may be shorter than that of a diesel generator.


Diesel is a less flammable fuel and it is easily obtained. There are companies that can deliver diesel to you. With proper maintenance, diesel engines can have longer life spans than an engine fueled by natural gas. This is why diesel may be ideal if you live in an area of Minnesota, Wisconsin, or North Dakota that deals with a lot of outages. Diesel also works better in the very cold conditions that the northern states are known for in the winters. If you find yourself in a high use situation, then the long-term cost of operating the generator is going to be lower.

The downfalls is that diesel does have a shelf life that doesn’t exceed 24 months without any additives, you may have to have diesel storage tanks installed, engine noise is higher, and the emissions are higher than natural gas. There is also a phenomenon called “wet stacking” that can occur if the load is ultra light, which is 40% of the rated output and that can cause the unit to smoke due to carbonized injectors. Running a heavy load can clean that up.

Liquid Propane

Liquid propane burns clean, has a long shelf life, and is easily stored in tanks. When you have a tank installed, you can opt to have your propane delivered to you. The engine is quiet, units with air-cooled engines are budget priced, and “wet stacking’ is not a problem.

The downfalls are that the gas is flammable and the generator contains a more complicated fuel system, which increases its chances of failure. The installation cost does go up when fuel plumbing is involved and the fuel can be more expensive than diesel. If you have a large propane tank on your property, it may not be very aesthetically pleasing.

Knowing these different types of fuel and what their pros and cons are can help you choose the proper standby generator for you. You can review your options with your generator company in order to find what will work best for your home or business, your budget, and power outage frequency.