Alternative Fuel Credit. You can claim a credit against your income tax liability for the cost of converting your motor vehicle to operate on an alternative fuel. Your credit is equal to 50% of the cost to convert your motor vehicle for a maximum credit of up to $1,000. In order to qualify for this credit, your motor vehicle has to be licensed in Montana and the conversion has to be from gasoline to an alternative fuel, such as natural gas, liquefied petroleum gas, liquefied natural gas, hydrogen, electricity, or other combinations. This credit should not be confused with the federal deduction for the purchase of a qualified clean-air vehicle.