Is ethanol a logical alternative fuel?

Is ethanol a logical alternative fuel?

I think all Americans can agree that it is important to reduce our dependence on foreign oil to fuel our industry and automobiles, or even our toys for that matter, but the question is what are logical alternatives?

Alcohol, of which ethanol is a form, has been used as a fuel for hundreds of years, and has been used as an internal combustion fuel on and off for the last century or so. There’s no real debate about those facts. Comparing ethanol to gasoline we find that the energy contained in a gallon of ethanol is about 51% of the energy found in a gallon of gasoline. Therefore it’s logical to assume that we will need more ethanol to do the same work when compared to gasoline. Keeping the comparison between the two fuels to that very narrow perspective gasoline obviously comes out way on top, but the arguing point is that alcohol is renewable and can be home grown. Those are again clear facts, but then we become bogged down in the debates over cost to produce, environmental impact, government subsidies, and seemingly endless other arguable facts.

There are two clearly defined sides in the debate. Pro-ethanol and anti-ethanol. Each side will present evidence to support their own agenda, of course, making the truth almost impossible to determine. After quite a bit of research I’m still not at all sure that I have the truth, or the whole truth but this is what I believe to be the unbiased truth with regard to ethanol.

Considering all energy required to produce ethanol including the fuel required to run the tractor to plant it and the fuel required to ferment and distill it; everything conceivably needed to produce ethanol related to energy we net about a 25% gain from the potential energy produced by burning it. Whether 25% is worth the effort is another debate but at least I’m satisfied that there is a gain. I’ve seen numerous claims otherwise. Let’s proceed with the notion that the 25% gain is worth while.

The obvious advantage of this fuel is that we got it primarily from renewable home grown corn, not from a potentially hostile foreign source. The money spent for the most part stayed within the United States. Mixing ethanol in gasoline at a 10% ratio raises the octane level of the mix and causes the fuel to burn with less of some emissions. What’s the down side?

In order to produce the ethanol a portion of the available food lots had to be dedicated to production of the raw material. It takes a bit more than 25 pounds of corn to produce a gallon of ethanol, for instance. It also takes a certain amount of fuel to plant, harvest, and produce ethanol and that fuel is primarily hydrocarbon, which is of course mostly oil based, which comes from those hostile foreigner; so did we really keep the money in the States? The corn requires a quantity of fertilizer to produce and the resulting nitrates pollute the drinking water supply and the run off pollutes the streams, rivers, and oceans. There’s a bigger dead zone in the Gulf of Mexico attributable to this nitrate run off than there is from the record oil spill. Of course most of that runoff can likely be attributed to food production rather than ethanol corn, but ethanol production is adding to it. Another issue with ethanol blended with gasoline is that as the level of ethanol is increased, energy output and fuel economy decrease, even though the octane level increases. And then there are the well recorded harmful affects of ethanol on the fuel system components because of the corrosive and high detergent nature of ethanol. It seems that engines and systems designed for gasoline aren’t necessarily compatible with ethanol even in small quantities. There may be more downsides to ethanol use but this is enough for now. We can see from this short discussion so far that the list of problems exceeds the list of advantages, which brings the question to my mind, is it logical to pursue ethanol as an alternative and renewable energy source?

Surprisingly the answer isn’t a clear and unequivocal no, and I support continued research and development. The need for alternative fuels is so clear and pressing that we as a nation would be foolish not to pursue every possible avenue of energy independence. In the last few years many alternative sources of ethanol have developed and the processing cycle has become more efficient. It is therefore entirely possible and probable that the 25% energy gain will be increased dramatically and the nitrate problem can be reduced considerably as well. Further good news is that the alternative sources of ethanol will not depend so heavily on traditional food sources, and consequently remove the pressure on food lots dedicated to fuel. What about the efficiency though? Remember it only has a fraction of the energy contained in an equal quantity of gasoline. The answer partially lies in the fact that it naturally has a much higher octane than gasoline, without the need for additives. Engines designed around the use of ethanol can be designed with much higher compression ratios and therein lays one of the biggest keys to literally squeezing more performance out of the fuel. With current technology we can obtain approximately the same fuel economy from ethanol as we can from pure gasoline if it is run in an engine specifically designed for ethanol fuel. Pure ethanol. Therefore the logical approach may be to pursue ever more efficient production of ethanol fuel, and engines designed to run on it, rather than trying to force feed ever increasing quantities of ethanol into gasoline engines.

There’s also some interesting research being done on vehicles equipped with dual fuel tanks; one for ethanol and another for gasoline. By injecting the needed fuel into the engine depending on operating conditions efficiency can be maximized, and the phase separation problem associated with the ethanol/gasoline blend can be more effectively controlled. It may work out but I’m betting on the pure ethanol approach mentioned above. It sounds simpler and simple usually equates to reliability.

Another topic of worthy discussion may be biodiesel. With current technology we already have an energy gain of 91% with biodiesel fuel. It’s renewable, home grown, and surprisingly the emissions from cutting edge diesel engines are already lower in most respects than the emissions possible from ethanol, the supposed green fuel. And the fuel economy can be unbelievable.