Generator Running Costs: Natural Gas vs Propane vs Diesel (2026 Fuel Prices)
Exact per-hour and per-day running costs at 50% and 100% load for each generator size and fuel type. Not vague ranges. Real numbers with a calculator.
Updated 11 April 2026
Running Cost Comparison
Costs at 50% load (typical during an outage) and 100% load (all circuits running simultaneously). Most generators run at 30-60% load during a real outage.
| Size | Fuel | $/hr (50%) | $/hr (100%) | $/day (50%) | $/day (100%) |
|---|---|---|---|---|---|
| 10 kW | Natural gas | $0.80 | $1.60 | $9.60 | $19.20 |
| 10 kW | Propane | $2.10 | $4.20 | $25.20 | $50.40 |
| 16 kW | Natural gas | $1.20 | $2.50 | $14.40 | $30.00 |
| 16 kW | Propane | $3.20 | $6.50 | $38.40 | $78.00 |
| 22 kW | Natural gas | $1.80 | $3.50 | $21.60 | $42.00 |
| 22 kW | Propane | $4.50 | $9.00 | $54.00 | $108.00 |
| 48 kW | Natural gas | $3.50 | $7.00 | $42.00 | $84.00 |
| 48 kW | Propane | $9.00 | $18.00 | $108.00 | $216.00 |
Based on 2026 average fuel prices: natural gas $1.20/therm, propane $2.80/gallon. Actual costs vary by region and supplier.
Running Cost Calculator
Estimate your fuel cost during an outage.
Estimated Daily Fuel Cost
$21.60
$1.80/hour at 50% load
Fuel Consumption Rates
| Size | Natural Gas (50%) | Natural Gas (100%) | Propane (50%) | Propane (100%) |
|---|---|---|---|---|
| 10 kW | 65 cu ft/hr | 130 cu ft/hr | 0.75 gal/hr | 1.5 gal/hr |
| 16 kW | 100 cu ft/hr | 200 cu ft/hr | 1.15 gal/hr | 2.3 gal/hr |
| 22 kW | 140 cu ft/hr | 280 cu ft/hr | 1.6 gal/hr | 3.2 gal/hr |
| 48 kW | 275 cu ft/hr | 550 cu ft/hr | 3.2 gal/hr | 6.4 gal/hr |
Natural Gas vs Propane: 10-Year Cost Comparison
Natural Gas
Connected to utility line. Never runs out. Cheapest per hour to operate.
Propane
Works anywhere. Requires on-site tank. Higher operating cost per hour.
10-year fuel savings with natural gas: approximately $1,940. However, if you do not have natural gas service, running a new line ($3,000-$5,000) may offset the savings. Check current propane prices at PropaneCostPerGallon.com.
Propane Tank Sizing
| Tank Size | Install Cost | Refill Cost | Runtime at 22kW (50%) | Runtime at 22kW (100%) |
|---|---|---|---|---|
| 250 gallon | $800 - $1,200 | $550 - $700 | 130 hours (5.4 days) | 65 hours (2.7 days) |
| 500 gallon | $1,200 - $2,000 | $1,100 - $1,400 | 260 hours (10.8 days) | 130 hours (5.4 days) |
Usable capacity is approximately 80% of tank size (tanks are not filled to 100% for safety). Runtime calculated on usable capacity. Propane tanks filled before hurricane season are cheaper; prices spike during and after storms.