Inputs
-
Miles per year per truck: 40,000
-
Diesel MPG: 10.5
-
CNG MPG: 10
-
Diesel price: $3.90/gal
-
CNG utility price: $1.40/GGE
-
Compressor: 2.8 GGE/hr
-
Electricity: $0.12/kWh
-
Energy required: 2 kWh/GGE
https://truckranch.com/blog/the-real-cost-of-owning-a-diesel-vs-gas-truck-in-2025
Diesel Fuel Calculations
Diesel Fuel Cost Calculation
Step 1 – Annual gallons used
Annual gallons used = Miles per year ÷ Diesel MPG
Example: 40,000 miles/year ÷ 10.5 MPG = 3,809.52 gallons/year
Step 2 – Annual fuel cost
Annual diesel fuel cost = Annual gallons × Diesel price per gallon
Example: 3,809.52 gallons × $3.90/gal = $14,857.14
Rounded annual diesel fuel cost per truck: $14,857
Step 3 – 5-year fuel cost
5-year diesel fuel cost per truck = Annual diesel fuel cost × 5
Example: $14,857.14 × 5 ≈ $74,285.71
Rounded 5-year diesel fuel cost per truck: ≈ $74,286
CNG Fuel Calculations
CNG Fuel Cost Calculation
CNG cost has three components:
• Utility gas price
• Electricity for compression
• Compressor capital cost
Step 1 – Annual GGE required
Annual GGE required = Miles per year ÷ CNG MPG
Example: 40,000 miles/year ÷ 10 MPG = 4,000 GGE/year
Step 2 – Utility gas cost
Annual utility gas cost = Annual GGE × Gas price per GGE
Example: 4,000 GGE × $1.40/GGE = $5,600 per year
5-year utility gas cost: $5,600 × 5 = $28,000
Step 3 – Electricity cost
Energy per GGE = 2 kWh
Electricity price = $0.12/kWh
Electricity cost per GGE = 2 × $0.12 = $0.24/GGE
Annual electricity cost: 4,000 GGE × $0.24/GGE = $960
5-year electricity cost: $960 × 5 = $4,800
Step 4 – Compressor capital cost
Compressor price = $35,000
Federal refueling credit = 30% → $35,000 × 0.30 = $10,500
Residual value after 5 years = 40% → $35,000 × 0.40 = $14,000
Net compressor cost over 5 years:
($35,000 − $10,500) − $14,000 = $10,500
Fleet CNG usage over 5 years (4 trucks): 4,000 GGE/year × 5 years × 4 trucks = 80,000 GGE
Compressor cost per GGE: $10,500 ÷ 80,000 GGE = $0.13125/GGE
Annual compressor cost per truck: 4,000 GGE × $0.13125/GGE = $525
5-year compressor cost per truck: $525 × 5 = $2,625
Total CNG Fuel Cost per Truck (5 Years)
Utility gas (5 years): $28,000
Electricity (5 years): $4,800
Compressor (5 years): $2,625
Total 5-year CNG fuel cost per truck: $35,425