I don’t normally post but I’m looking at a Ford truck which can be converted to a bi-fuel (runs on gas or CNG) and has a 22 gallon CNG tank in the bed.
Looking at the following estimates:
Gasoline mileage: 13 city – 18 hwy
CNG: 11 city – 15 hwy
Currently 86 octane gasoline in my area was at $3.45 yesterday and CNG was $1.14 gge. (CNG in OK is cheap right now. Gallon Gas Equivalent = gge)
City Gas mileage:
$10/$3.45 = 2.8985 gallons
2.8985 gallons x 13 mpg = 37.68 miles
City CNG mileage: $10/$1.14 = 8.7719 gge
8.7719 x 11 mpg = 96.491 miles
Does my math check?
I’m just starting to check into the whole CNG vehicle thing but I’ve noticed a few things:
1: CNG fueling pressures vary. A good fill is 3,000 to 3,400 psi. Many of the current CNG pumps don’t deliver a consistent psi fill rate.
2. CNG fuel has a higher octane than regular gas but you get 12% to 15% less mileage from an equivalent amount of fuel. (However, I’ve seen E85 mileage rates as being 30% to 35% less than gas = Advantage CNG)
3. CNG is only attractive if the price spread between gas and CNG makes it a “good” deal. It will only take the states so long until they tax CNG at gasoline levels thus eliminating the spread. Then we are back at square one again.