Pay Back Calculation
FACTS AND ASSUMPTIONS
Fuel consumption @ 1000 kW: 70 gph (100% diesel)
Hours per year: 8000
Gas/Diesel ratio: 65%
Diesel cost ($/gal): $2.45 per gallon
Natural gas cost ($/mcf): $4.60 per mcf
hhv of #2 diesel: 140,000 btu/gal
hhv of natural gas: 1,000 btu/scf
Gas Equivalent Gallon (GEG): 140 scf/gal
100% DIESEL OPERATION
Diesel use per hour: 70 gallons
Diesel cost per hour: $171.50 (70 x $2.45)
Diesel cost per year: $1,372,000 ($171.50 x 8000)
BI-FUEL OPERATION
Diesel use per hour: 24.5 gph (70 x 0.35)
Diesel cost per hour: $60.03 (24.5 x $2.45)
Gas use per hour: 6370 scf (70 x 0.65 x 140)
Gas cost per hour: $29.30 (6370/1000 x $4.60)
Total fuel cost per hour: $89.33 ($60.03 + $29.30)
SAVINGS
Bi-Fuel Savings per Hour: $82.17 ($171.50 - $89.33)
Bi-Fuel Savings per 8000 hours: $657,360.00 ($82.17 x 8000)
*PAYBACK (FUEL ONLY)*-
Time it takes for the Bi -fuel system to pay for itself.
Payback (YEARS): 0.08
PAYBACK (WEEKS): 4
PAYBACK (DAYS): 29
The savings realized by running the GTI Bi-Fuel System is directly related to the cost of diesel fuel, cost of gas, and the number of hours of operation. The following is an example is a cost comparison between running a 1000 kW generator on 100% diesel and on Bi-Fuel with a 65% gas-to-diesel ratio in continuous operation. A number of assumptions are made in this example which are clearly stated in order to clarify the calculations.