Giovanni Di Nicola1, Eleonora Santecchia1, Giulio Santori2 and Fabio Polonara1

1Dipartimento di Energetica, Universita Politecnica delle Marche, Ancona Universita degli Studi e-Campus, Via Isimbardi 10, Novedrate (Co)

Italy

1. Introduction

Henry Ford, father of the modern automobile, constructed his Model T in the early years of the 20th century, when he planned to fuel it with ethanol obtained from cereals. Ford promoted the use of this fuel with such conviction that, by 1938, plants in Kansas were already producing 18 million gallons of ethanol a year (about 54,000 t/year). But interest in ethanol declined after the Second World War because of the enormous availability of natural gas and oil.

At the end of the Seventies, following the first oil crisis, various oil companies began to sell a petrol containing 10% of ethanol, called gasohol, taking advantage of the tax deductions granted on ethanol. Bioethanol did not immediately meet with the success it deserved, however, because it already had competitors on the market, such as methyl tert-butyl ether (MTBE), which was better than ethyl tert-butyl ether (ETBE) in both economic terms and performance. In subsequent years, MTBE proved to be heavily polluting, so it was banned and bioethanol returned to become one of the most attractive prospective solutions for reducing CO2 emissions.

Another factor that helped to relaunch bioethanol was the growing awareness that we are nearing the so-called tipping point, i. e. the moment commonly indicated as the critical point of no return, when the curve of the demand for oil intersects the declining curve of its availability.

There is an ethical issue, however, that particularly concerns bioethanol, but also affects the other fuels of biological origin. Biofuels are obtained mainly from raw materials such as plants and cereals, that would otherwise be destined for the foodstuffs industry.

To deal with this problem, recent research has been concentrating on an inedible perennial herbaceous plant called Miscanthus giganteus that has a calorific value of approximately 4200 kcal/kg of dry matter. Using lignocellulose materials, municipal solid waste or the wheat wasted each year (around 5%, which would provide about 9.3 Gl of bioethanol) could also overcome the ethical obstacles.

Bioethanol can be used in various forms: added in proportions of 5-10% to the diesel oil in diesel engines; mixed in proportions of 10-85% in petrol for internal combustion engines, or to replace 0-100% of the petrol used in flexible fuel vehicles (FFV). The number of FFV on the roads is constantly increasing: in Brazil their sales now reach 400,000 vehicles/year and

there are approximately 1,500,000 of them (mainly public vehicles) circulating in the USA; in Europe, Sweden has around 15,000 vehicles of this type fueled with E85 (85% ethanol). Research is also underway on improved engines fueled with bioethanol, and on fuel cells that use the internal reforming of bioethanol to obtain hydrogen.