Fuel Types Compared: Gasoline, Propane, Dual-Fuel, Battery and Solar
The best fuel is the one you can reliably get and safely store when the power is out. Gasoline is the easiest to find but the hardest to keep fresh. Propane stores for years. Batteries need no fuel but have a fixed amount of energy.
Gasoline
Gasoline is available almost everywhere and gives the highest output from a given engine. The downside is shelf life. Untreated gasoline starts to degrade within a few months, and stale fuel can gum up the carburetor. A fuel stabilizer extends storage time. Gas stations also may be closed or out of fuel after a storm, and pumps need electricity.
Propane
Propane keeps almost indefinitely in a sealed tank, burns cleaner than gasoline and leaves less residue in the engine. Expect roughly 10 percent less output than the same engine on gasoline. A standard grill-size cylinder lasts only a few hours under heavy load, so plan on several cylinders or a larger tank.
Natural gas
A unit hooked to your home's gas line can run as long as the supply stays on. Output drops somewhat compared with gasoline, and the gas supply can be shut off in major disasters. Standby generators almost always use natural gas or propane.
Dual-fuel and tri-fuel
Dual-fuel generators run on gasoline or propane with a switch, which is the best flexibility for the money. Tri-fuel models add natural gas. If one fuel runs short, you switch to the other.
Diesel
Diesel engines are durable and efficient under load, but diesel generators are heavier and more expensive. They are more common in commercial settings than in home use.
Battery and solar
Power stations store energy in a battery and require no fuel at all. You recharge them from the wall, a car or solar panels. With enough panels, a power station can run indefinitely in daylight, but charging speed is limited by sunshine and panel size. Our guide to solar generators and recharging explains how it works.
Comparison
| Fuel | Storage life | Output vs. gasoline | Available in a long outage | Main drawback |
|---|---|---|---|---|
| Gasoline | Months (longer with stabilizer) | Baseline | Often scarce | Goes stale; fire risk |
| Propane | Years | About 10% lower | Depends on your tank stock | Cylinders empty quickly |
| Natural gas | Continuous supply | Lower | Usually, unless the line is shut off | Needs a fixed hookup |
| Diesel | About 6 to 12 months | Strong under load | Often scarce | Heavy and costly |
| Battery or solar | Stays charged for months | Limited by battery size | Sun-dependent | Finite energy per charge |
Storing fuel safely
- Use approved containers and keep them outside living spaces
- Check your local fire code for how much you may store
- Keep fuel away from heat sources, pilot lights and the generator itself
- Never refuel a running or hot generator; let it cool first
Browse Fuel Generators, including dual-fuel models, or Solar Panels.