ETHANOL IN GASOLINE?

 

In the process of becoming a mechanical engineer I was required to take a course called “fuels and lubricants”. I know that you are probably thinking that a course with a title like that must have been fun and exciting, right. For the record it was neither but I did learn things that have been useful to me for thirty five years in my career. I can read a report by the EPA, American Petroleum Institute or the ethanol producers association and understand when actual science is being used to explain an issue and when it is being used to cloud the issue.

THE MILEAGE/FUEL EFFICIENCY DEBATE

The idea of biofuels is not new, Rudolf Diesel invented his engine in 1894 in part to allow farmers to burn biodiesel that they could make themselves. Fords first cars were alcohol fueled before turning to the cheap and available gasoline. The principle argument that was made in favor of adding ethanol to gasoline before the Congress mandated it in 2007 was that it would reduce our dependence on foreign oil. Chemical giant Archer Daniel Midland lobbied in favor of the mandate and congressional members from corn growing states pushed for passage of the mandate. Here however science gets in the way of their argument. Ethanol only produces 2/3 of the energy per gallon that regular gasoline does. Cars operated on 10% ethanol blended fuel get 13% fewer miles per gallon. The darned arithmetic just doesn’t work out. You cannot come out ahead by saving 10% when it costs you 13% more fuel to go the same distance. Compounding the problem for the folks preaching the energy savings is that it takes a lot of energy to make a gallon of ethanol. The energy available in the average gallon of ethanol is 76,330 BTU while the total energy required to produce it is 81,090 BTU. Again the darned math just doesn’t work out in favor of putting ethanol in our fuel.

THE ENVIRONMENTAL DEBATE

The argument in favor of including ethanol in automobile fuel from the environmental perspective is that ethanol produces 20% less carbon monoxide and 2% less carbon dioxide for each gallon burned than for the same volume of  gasoline. The nitrous oxide produced by burning ethanol is higher than it is for gasoline so environmentalists tend not to use it in their arguments. The statistics above showing reductions in the CO and CO2 emissions makes it sound like there is a real advantage to adding the ethanol to our fuel. The darned science gets in the way again though. If you read the top of this paragraph again note that the figures are given as amounts of pollutant/gallon. Once you take into account the extra fuel that you must burn to drive the same distance it turns out that you actually make more pollutants per mile traveled.

WHAT ABOUT OVERALL ECONOMY

The old adage about being able to learn all you need to know about something by following the money is useful in this discussion. Ethanol costs about 57 cents more per gallon than the average gasoline at the pump. The petroleum companies that refine oil for gasoline and blend the fuel we pump into our tanks have petitioned Congress to remove the Ethanol mandate stating the same arguments I have repeated above. EPA regulations enforcing the congressional mandate required fuel blenders to mix 13.8 billion gallons of ethanol with their gasoline in 2013 based on a 2005 study that predicted that this volume would yield about a 10% mix. The slow economy coupled with higher mileage vehicles have reduced the fuel consumed so much that the blenders are unable to use 13.8 billion gallons of ethanol when using a 10% mix. Newly proposed EPA regulations to requiring 15% ethanol blends have prompted auto makers to state that burning such blends will void engine warrantees. The solution for the blenders comes in the form of credits that they can buy to avoid blending fuels with the higher ethanol content. We are finally getting to the real driving force behind the regulations. Credits that cost 7 cents per gallon in January 2013 before the proposal of new blends cost over a dollar a gallon by early March once the text of the new regulations was known. Blenders are forced to add the higher cost less efficient and dirtier ethanol to our fuel and pass along the cost to consumers. It now appears likely that the cost of purchasing the credits will need to be passed along also as another hidden tax. The cost of corn for animal feed has skyrocketed, making retail food costs soar.

WHY ARE WE DOING THIS

From the engineering prospective it makes no sense to blend ethanol into our fuel. It is less efficient and because it absorbs water out of the air it cannot be stored long before it goes bad. The only reason to continue this failed program is because ethanol producers make big campaign contributions and Congressmen from corn growing states garner votes with it. The government has no incentive to stop it because it gets a windfall of money out of the credits purchased. The only thing eternal is a failed government program so it appears that this farce is going to be expanded. Is there any wonder why we have seen the price of fuel more than double in the last five years.

Before sending comments to me about how much better the efficiency numbers are once you increase the compression ratio of the engine. I know this and that the higher octane of the ethanol allows for this increase in compression ratio. The problem with this argument is that the existing engines in our cars are not built to produce the higher ratios.