Ethanol: an alternative source of energy

By Roberto Salomón

From CUBASOLAR’s quarterly Energía y Tú, No. 29, January-March 2005
 

Ethanol, one of sugar cane’s best known by-products, is in full swing in Cuba today since, in addition to its usefulness in the production of beverages, its qualities as an alternative fuel are under study.
 

Indeed, as tens of thousands of liters are used to produce alcohol and spirits, the Ministries of Sugar (MINAZ) and Transportation (MITRANS) are conducting joint research into its possibilities to propel vehicles.
 

The most recent studies –under way since 1997– resulted in certain combinations of regular gasoline and ethanol setting in motion 114 vehicles of the two branches which traveled an overall distance of a million and a half kilometers, as confirmed by specialists from CETRA (Transportation Research and Development Center) and the sugar cane institutions.
 

Both entities are working together to tackle the lack of sufficient fossil fuels, a critical problem which made them think about renewable energy sources.


Begun at CETRA, the first stage of this study led to the initial conclusion that, under the existing circumstances in Cuba, a stable, efficient mixture could be reached by adding 20-25% of ethanol to regular gasoline, as was evidenced by benchmarking and laboratory tests.
 

That such proportion increases gasoline’s octane number was proved in experiments performed at Habana province’s sugar mill ‘Camilo Cienfuegos’ that yielded more positive than negative results. Work was thus extended to other mills, like the nearby ‘Héctor Molina’, ‘Manuel Martínez Prieto’ in the capital city, and ‘Antonio Guiteras’ in Las Tunas province.
 

Experts from both fields agree that these ethanol and gasoline mixtures will be marketed depending on the economic situation. In the meantime, the country continues its preparation in this sphere, taking into account that fossil fuels tend to run out.
 

CETRA manages research and MITRANS controls the transportation policies, whereas the sugar cane industry provides both the ethanol and the vehicles needed for experimenting, which also includes the effects of mixing ethanol and diesel.
 

A combination of ethanol and gasoline –called mofuco– was employed in Cuba during World War II owing to the wartime-related fuel shortage, and a few times afterward, but its use never became widespread.
 

There are references of further studies made in Cuban laboratories in 1951, and 10 years after that, on a combination of ethanol and gasoline with different tetraethyl lead contents. Five years later, the then Empresa Consolidada del Petróleo researched into and made experiments with stabilizers for mixtures of hydrated alcohol and gasoline.
 

Another 10 years passed by before the Centro de Desarrollo de la Industria del Petróleo tested various types of gasoline base and a number of mixtures. One of them consisted of 15% ethanol for cases with octane numbers below 83.
 

Similarly, the Instituto Cubano del Petróleo studied the possibilities of mixtures with a 30% sugar cane alcohol component.
 

As is evidenced by the above research works and those currently in progress at CETRA and some MINAZ’s institutions, these mixtures not only increase the octane numbers and reduce toxic gas emission and environmental pollution, they make it possible as well to import less oil and gasoline and have more fuel for motor vehicles.     
 

Nor is it by accident that the German Peter Baron, executive director of the International Sugar Organization, said in a recent visit to Cuba that ethanol –and other derivatives– will allow worldwide sugar workers to survive this produce’s current low prices.
 

With more than four million cars operating with either this mixture or only ethanol, Brazil is at this moment where the greatest advance has been made in this regard, what with its production of over 15 billion liters for that purpose, a figure expected to increase noticeably this year.
 

Plans have been developed as well in the United States to extend the use of ethanol, and other countries like Germany, Kenya, Zimbabwe, Canada, Mexico, Sweden, Italy, Spain, India, Ukraine, Australia, South Africa and Cuba, among others, are also working on it for economic or ecological ends.

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What’s ethanol?

A.k.a. vinic alcohol or ethyl alcohol, ethanol (C2H5OH) is a clear, colorless liquid with a characteristic odor and a burnt taste, widely used to produce beer, wine, brandy and other spirits. It’s typically found in dissolved solutions, mainly with a 95% ethanol and 5% water volume.

Ethanol is obtained by fermentation of sugars from potato starch, sugar cane, corn and other cereals through a process practiced since ancient times all the way up to the present-day production of a large part of industrial ethanol. Its fermentation reaction (C6H12O6  2C2H5OH + 2CO2) produces some additional substances as a result of yeast impurity. The liquid thus fermented contains between 7 and 12% ethanol, so some distillation is required to achieve higher concentrations, which is made possible by its boiling point (78.5 °C), lower than water’s.