The XIX International Symposium on Alcohol Fuels (ISAF) has taken place on October 2011 in Verona (Italy). ISAF gathers together specialists, technologists, executives, and technical experts from alcohol, alcohol fuels, methanol, ethers, and biofuel industries, under the scientific coordination of the ISAF International and National Organising Committees. The topic of XIX ISAF has been the “Development and utilization of alcohol fuels, to promote sustainability”. A number of papers presented at this conference have been selected based on scientific excellence and invited to submit a full article. The papers accepted after passing the peer-review process are presented within this issue.

Two articles investigated issues related to the feedstock.

  • Wetterlund et al. address the optimal use of forest residues. They concentrate on comparing more traditional heat and power generation applications with second generation biofuel production. A model is developed and applied to carry out this analysis, focusing on the influence of different economic policies (like carbon tax or biofuel support). In order to achieve a 3 % s generation (2G) biofuel market penetration a biofuel support equal to today’s tax exemption is needed, while a carbon tax policy would drive the feedstock towards CHP generation potentially replacing 15 % of current fossil heating within the EU. Considering a maximum forest residue use, biofuel support would generate a reduction of 80–150 MtCO2/year, while a reduction of more than 200 MtCO2/year could be reached from the same biomass utilization if a carbon tax is adopted. The area around the Baltic Sea (Sweden, Finland and Baltic Countries) could be the major EU contributor of forest residues for second generation biofuel production, with a potential of more than a third of the total EU second generation biofuel demand assuming adequate biofuel support policies throughout the EU. On the other hand, Italy would be the largest importer.

  • Leal et al. investigate sugarcane as an energy feedstock showing among others that a significant amount of surplus electricity is generated today in modern sugar mills of Brazil, Mauritius and Reunion Islands, Guatemala, and India. Thus, not only the sugar content of the cane matters, but the whole energy content of the feedstock should be valorized either as energy or fuel. This is not state of technology yet; currently less than 30 % of the cane energy content (7,400 MJ/t) is converted into useful products. The analysis show that huge improvement potentials exist, especially through the integration of first and second generation (lignocellulosic) ethanol technologies. This will also considerably influence the sustainability of bioethanol. Even due the fact that first-generation sugarcane ethanol is already classified as advanced biofuel by the International Energy Agency the integration with second-generation processes will further improve the performance of this crop. The ethanol yield per area is the key element for sustainability: today, more than 90 % of the fossil energy consumption and greenhouse gas emissions (without land use change/indirect land use change emissions) in the ethanol’s lifecycle results from the agricultural area, and around two thirds of the ethanol production costs is allocated to the feedstock. Energy cane ethanol could save 36 % of land compared to conventional ethanol. Due to sustainability aspects by implementing such concepts great attention should be given to the estimation of the optimal amount of biomass to be left on the field.

Three articles concentrated on fuels and chemicals production.

  • Casa et al. study the synthesis of C10 o C16 linear ethers from 1-alkanols over acidic ion-exchange resins. The linear ethers above nine-carbon-atoms (like ethyl octyl ether, di-n-pentyl-ether, di-n-hexyl ether, di-n-octyl ether) can be blended to diesel to improve the environmental performance of the fuel. Ethanol is usually blended with gasoline. However, 1-alkanols can be potentially produced from ethanol, and etherification of such alcohols and co-etherification with ethanol can be two different ways of introducing bioethanol-derived additives into diesel fuels. Gel-type and macroreticular poly(styrene/divinyl benzene) resins were investigated in this work.

  • Lavoie et al. examine the thermal conversion of nonhomogeneous residual biomass from urban wastes as well as from forest and agricultural operations into an ultrapure syngas used for the thermocatalytic synthesis of methanol, a major building block for fuels and chemicals synthesis. The process concept here described is composed by staged gasification, syngas conditioning, methanol production from syngas and conversion of methanol into ethanol. Technology was upscaled in 2009 to 2011 and production of biomethanol feeding 1.5 t/h is ongoing in a demonstration plant in Westbury (Québec), while the conversion of methanol to ethanol was proven at bench scale level.

  • Carotenuto et al. evaluate the production of chemicals, such as acetaldehyde, ethyl acetate, and hydrogen, from ethanol, testing reactions in a packed bed reactor operated in a wide range of temperature, pressure, and space–time. The scope of this work is to demonstrate that by varying properly the operative range of residence time and pressure, it is possible to obtain with high selectivity acetaldehyde or ethyl acetate from ethanol in a single reaction step using commercial catalysts.

Finally, one paper focuses on end use.

  • Nylund et al. benchmark heavy-duty ethanol vehicles against diesel and compressed natural gas vehicles. Addressing the use of alcohol fuels in modified heavy-duty vehicles is important to promote the penetration of ethanol in diesel-dominated markets. The investigated ethanol technologies demonstrate fuel efficiency almost as good as conventional diesel engines. Particulate emissions were reduced compared to Diesel without particulate filter, as well as NOx emissions. No major vehicle or fuel-related problems were reported so far.

All over the papers show clearly that even due the long history of bioethanol and thus the significant developments and scientific achievements so far there is still a wide field of improvements and additional developments. Thus the bioethanol story is after more the 100 years not at an end. The bioethanol development is just at the beginning and will show new and unexpected results in the years to come.