Choosing the Right Generator Fuel: Pros and Cons of Diesel, Gasoline, Propane, and Natural Gas Generators

Generators are critical components for backup power in commercial, industrial, and residential settings. But choosing the right type means understanding the fuel options available, their advantages, and their limitations.

This article compares the most common generator fuels—diesel, gasoline, propane (LPG), and natural gas—to help you select the best fit for your application, budget, and operational needs.

1. Diesel Generators

Pros

• Durability & Longevity: Diesel engines are built ruggedly and often last longer than gasoline engines.

• Fuel Efficiency: Diesel fuel has a higher energy density, offering better fuel economy.

• Reliability: Diesel generators handle heavy loads and frequent startups well.

• Safety: Diesel fuel is less volatile and less prone to evaporation or explosion.

• Availability: Diesel is widely available and commonly used in commercial/industrial settings.

Cons

• Noise: Diesel generators tend to be louder than other types.

• Maintenance: Require regular maintenance to manage fuel quality and engine wear.

• Cold Weather Sensitivity: Diesel fuel can gel in cold climates without additives or heaters.

• Emissions: Higher NOx and particulate emissions unless equipped with advanced filters.

2. Gasoline Generators

Pros

• Lower Initial Cost: Gasoline generators typically cost less upfront than diesel units.

• Quieter Operation: Generally produce less noise than diesel engines.

• Readily Available Fuel: Gasoline is easy to obtain and store for short periods.

Cons

• Fuel Stability: Gasoline degrades faster, especially when stored over months.

• Lower Fuel Efficiency: Gasoline engines consume more fuel per kWh generated.

• Safety Concerns: Gasoline is highly flammable and volatile, requiring careful storage.

• Shorter Engine Life: Less durable compared to diesel engines in heavy-use scenarios.

3. Propane (LPG) Generators

Pros

• Clean Burning: Produces fewer emissions and particulates, making it environmentally friendlier.

• Long Fuel Shelf Life: Propane can be stored indefinitely without degradation.

• Quiet Operation: Propane generators tend to run quietly.

• Safe Storage: Propane tanks are sealed and less prone to spills.

Cons

• Lower Energy Density: Propane has less energy per volume, resulting in slightly lower run times.

• Fuel Availability: May be less accessible in some remote or emergency situations.

• Higher Operating Cost: Propane fuel often costs more than diesel or natural gas.

• Power Output: Typically less power density compared to diesel or gasoline for the same size.

4. Natural Gas Generators

Pros

• Unlimited Fuel Supply: If connected to a natural gas pipeline, fuel supply is continuous.

• Cleaner Emissions: Burns cleaner than diesel and gasoline with lower CO and NOx emissions.

• Convenient: No need to refuel tanks manually during outages.

• Lower Operating Cost: Natural gas is often cheaper than propane or gasoline.

Cons

• Dependence on Utility Supply: If the natural gas pipeline is disrupted, generator won’t run.

• Installation Cost: Requires pipeline hookup, which can be costly or unavailable in some areas.

• Lower Power Density: Natural gas engines are typically larger for the same power output.

• Less Portable: Generally fixed installations rather than portable units.

Conclusion

There’s no one-size-fits-all when it comes to generator fuels. Diesel generators dominate heavy industrial use for their durability, while propane and natural gas offer cleaner, quieter operation suitable for residential and commercial sites. Gasoline remains popular for portable or infrequent use but comes with storage challenges.

By weighing the pros and cons of each fuel type, you can select the generator that best fits your power reliability needs, budget, and environmental goals.

References

• NEC 2023 Article 445 – Generators

• EPA Emissions Standards

• Fuel Suppliers and Manufacturer Data Sheets

• Local Utility and Fire Code Guidelines

Disclaimer:
The information, tools, and resources provided on this website are for general informational purposes only. While Empower Engineering strives to ensure accuracy and relevance, no guarantee is made regarding the completeness or applicability of the content to specific projects. Users are responsible for verifying all calculations, code interpretations, and design decisions with licensed professionals and local authorities. Empower Engineering assumes no liability for any loss, damage, or code violation resulting from the use of this website’s content.

Empower Engineering | July 15, 2025