Diesel vs Gas Generator: Comprehensive Fuel Comparison

Choosing between a diesel generator and a gas (natural gas or LPG) generator depends on fuel availability, operating costs, emissions requirements, and application type.

How Each Fuel Type Works

Diesel Generators

• Fuel: Diesel (EN590, ASTM D975 or equivalent)
• Combustion: Compression ignition (no spark plugs)
• Efficiency: 35-42% electrical efficiency
• Power range: 1kW to 3000kW+

Natural Gas Generators

• Fuel: Pipeline natural gas or CNG
• Combustion: Spark-ignited (requires spark plugs)
• Efficiency: 30-40% electrical efficiency
• Power range: 10kW to 2000kW

LPG/Propane Generators

• Fuel: LPG stored in tanks (liquid or vapor withdrawal)
• Combustion: Spark-ignited
• Efficiency: 30-38% electrical efficiency
• Power range: 5kW to 500kW

Head-to-Head Comparison

Factor	Diesel	Natural Gas	LPG/Propane
Fuel cost per kWh	$$	$	$$
Engine lifespan	20,000-40,000 hrs	15,000-30,000 hrs	15,000-30,000 hrs
Maintenance cost	Moderate	Lower (cleaner fuel)	Lower
Emissions	Higher NOx, particulates	Cleanest	Clean
Fuel storage	On-site tank required	Pipeline (no storage)	Tank required
Fuel stability	6-12 months (with additive)	N/A (piped)	Indefinite
Cold start	Good	Good with gas regulator	Good down to -40°C
Noise	Slightly louder	Quieter	Quieter
Power density	Highest	Lower	Lower
Price per kW	Baseline	10-20% higher	15-25% higher

Fuel Cost Analysis

Assumptions

• 500kW generator running 2000 hours/year at 75% load
• Diesel: $0.80/liter
• Natural gas: $0.35/Nm³
• LPG: $0.60/liter

Annual Fuel Cost

Metric	Diesel	Natural Gas	LPG
Annual consumption	180,000 liters	540,000 Nm³	220,000 liters
Annual fuel cost	$144,000	$189,000	$132,000

Note: Fuel prices vary significantly by region. Natural gas is cheapest where pipeline infrastructure exists. LPG is often most economical off-grid.

Application Recommendations

Choose Diesel When:

• Prime power / continuous operation: Diesel engines last longer
• Remote locations: Diesel is available everywhere
• High power density needed: Diesel delivers more power per engine size
• Fuel storage flexibility: Diesel stores well for months
• Existing diesel fleet: Common in mining, construction, oil & gas

Choose Natural Gas When:

• Pipeline is available: Lowest cost fuel with no storage
• Emissions regulations are strict: Cleanest combustion
• CHP / cogeneration: Heat recovery for building heating
• Indoor installation: Cleaner exhaust, simpler ventilation
• Utility peak shaving: Quick start and stop capability

Choose LPG/Propane When:

• No pipeline gas available: But want cleaner fuel than diesel
• Cold climate operation: LPG vaporizes at very low temperatures
• Long-term standby: LPG stores indefinitely without degradation
• Temporary power: Easy tank setup and removal

Dual Fuel Option

For maximum flexibility, dual-fuel generator sets can operate on:

• Diesel + natural gas: Diesel pilot ignition with natural gas primary
• Automatic fuel switching: Switch between fuels based on availability
• Fuel flexibility: Run on diesel only if gas supply interrupted

Dual-fuel generators offer:

Advantage	Benefit
Fuel flexibility	Use cheapest available fuel
Extended runtime	Switch fuel sources without shutdown
Emissions reduction	Gas mode for normal, diesel for backup
Energy security	Not dependent on single fuel source

Which Generator Does Pauway Offer?

Pauway Power manufactures both diesel and gas generator sets:

• Diesel: Cummins, Perkins, Yuchai, Shangchai engines — 20kW to 2500kW
• Natural gas: Spark-ignited engines — 30kW to 1000kW
• Biogas/Landfill gas: Specialized gas treatment — 50kW to 500kW
• Dual-fuel: Diesel-gas combination — 100kW to 2000kW

Choose Your Fuel Type

Contact Pauway Power to discuss which fuel type is most cost-effective and practical for your specific project.

Discuss Fuel Options →