Between the varieties of methods utilized to produce ethanol fuels and the different mixtures we find with ethanol fuel blends, there are a number of different types of ethanol we must consider in any discussion related to ethanol fuel alternatives. The differences in ethanol fuel, based on how they are made, what their application is, and the mixtures they are part of each play part to different factors.
Compared to fossil fuels, ethanol fuel has a relative low volatility. In applications such as typical gasoline engines, the ethanol fuel is usually E85 or lower. This means it’s a blend of 85% ethanol and 15% gasoline. This is used in standard consumer and light duty vehicles, or spark engine vehicles. The gasoline is used in these applications mainly to deal with cold start up and warming performance. Since ethanol has a difficult vaporizing at these low temperatures, the gasoline is needed. E95, or a 95% ethanol/5% gasoline mix is used in diesel or compression ignition engines. These vehicles don’t require as much a spark as most gasoline engines, but any less gasoline could provide for unacceptable start-up issues.
It’s also been shown that higher ethanol base fuels will lower the performance or mileage in most engines currently available. While tests have shown engines specifically designed for use with ethanol only would greatly enhance the performance, most engines today are known as dual-fuel engines, able to utilize either gasoline or ethanol, and most use a mixture of the two. Pending on regulations in your part of the world, ethanol may be required to be added. In some events, it is not ethanol that is required to be added to the fuel, but some type of additive that will otherwise lower the carbon dioxide output from a fossil fuel burning engine. In those events, with ethanol’s lower carbon dioxide output, it is a fast favorite as an additive.
Another thing to consider is the different ways ethanol fuel can be produced. There are both wet and dry mills, which are used to make ethanol. Dry mills take dry goods such as corn, grain seeds, sugar, etc., and have the ethanol extracted. This process is usually a little longer and more expensive, but a more pure ethanol is derived. The wet mills require soaking the grain or other natural product which the ethanol is to be extracted from, but this can lead to a higher water content within the ethanol or other issues, although it does typically prove to be faster. Different crops also produce different amounts of ethanol. Miscanthus, a low-input perennial grass, for example, produces a higher yield of ethanol than corn. So, when it comes time to consider how/where/when to produce ethanol, these factors must also be considered. Another factor that comes into play is a relatively new advancement, wherein companies that produce large amounts of a biological byproduct which ethanol can be extracted from. This is called cellulosic ethanol, and while there have been few if any drawbacks to utilizing these bio-mass byproducts, it is still a relatively new concept. This would be an ideal candidate to garner ethanol from, however, as it is essentially recycling waste.
