The New Green Technology - Part 2

A few weeks ago I published the first part of this column.  In it, I introduced you to two new technologies that could make our obscene use of ethanol unnecessary: natural gas engines—either conversions or replacement—and use of “pure” gasoline with no ethanol in it.

One of those ideas appealed to me, since I was preparing to go on a 6,000-mile road trip, so I decided to run a test and learn whether or not the pure gasoline would give me better mileage while reducing the cost of fueling.

Since I already knew that our 2005 Toyota Sienna averages 25 miles-per-gallon on road trips using the ethanol-laced gasoline, I went online and found gas stations along the route that provide the pure gas as an alternative.  I knew that is would probably be a little more expensive than the ethanol, but I was willing to pay extra to see how well it performed.

I started by using as much of the old gas as possible before I filled up with the pure gas. The tank was close to empty when I fueled up that first time just prior to the start of our trip. I continued to use only pure gas for about half of the trip, but I learned something else that caused me to alter my fuel choice.

It seemed that, regardless of my use or non-use of the ethanol gasoline, the only factor that changed my mileage was the level of octane in the gas.  Those pumps that gave me 85-octane caused mileage to dip below 25 mpg, while those in the 87-89 range provided a boost in mileage by 2-3 miles per gallon.

Most stations sell 87-octane as their regular gas and 89-octane as the mid-grade, while the premium is usually 91-octane.  The price difference per gallon averages about ten cents per gallon between grades.  Where I got the worst mileage, 23 mpg, was after I fueled up with 85-octane gasoline even if it was pure, unadulterated gas. With 87-octane pure gas, I got around 27 mpg, and 89-octane gave me over 28 mpg.

Since I was getting about 10-percent better mileage with the higher grades and I was only paying ten cents additional for each gallon, that worked out to a huge savings. My average of $3.50 versus $3.60 is only a difference of 3-percent. That means you get a three-fold advantage in using the higher grade of gasoline regardless of added ethanol.

Now let’s put that into a practical example.  Ten gallons of gas costing $35 will keep me on the road for 250 miles.  If I pay $36 and buy a higher grade I won’t have to refill for about 275 miles.  It is like getting an extra gallon of gas for $1. 

I don’t know how all this works out for the premium blend, because I never bought any of that, but if it has the same effect, it would mean paying $37 and driving around 300 miles before filling up again—another gallon for just a buck.

I invite you to try this out for yourself, although you probably won’t be able to buy the pure gas in any but the lowest octane. You’ll have to buy the ethanol if you want the higher octane grades.  It then becomes a case of which you prefer, better mileage or a cooler burning fuel, because the ethanol-added gasoline does burn a lot hotter and does cause more engine wear.

Now if we could just get the oil companies to quit mixing the ethanol in and sell all grades as pure gas, it would make a big difference in both mileage and engine wear to our advantage...  Well, I can dream.