Determination of the renewable energy content of chemically modified biofuels G. Toscano*, G. Riva, E. Foppa Pedretti, D. Duca Dipartimento di Scienze Alimentari, AgroIngegneristiche, Fisiche, Economiche e del Territorio, Universita ` Politecnica delle Marche. Via Brecce Bianche, 60131 Ancona (AN), Italy article info Article history: Received 24 November 2009 Received in revised form 4 April 2011 Accepted 15 April 2011 Available online 25 May 2011 Keywords: Biofuel Renewable energy content FAME ETBE MTBE abstract The recent EU directive on renewable energy sources (Directive 2009/28/EC) promotes the use of biofuel and bioliquids that could be produced through chemical processes. These biofuels consist of a biogenic (renewable) part and a non-renewable (fossil or non-biogenic) part. A method to evaluate the renewable and non-renewable energy fractions released during combustion is presented. The method is based on thermochemical criteria of bond dissociation energies and on the knowledge of the molecular structure of reagents and products. Its application to MTBE and ETBE analysis provided results that are close to those published in the directive. In particular, application of the method on these products points out a renewable fractions of 23.7% and 35.9% compared with the 22% and 37% listed by the RED. Moreover, the application of the method to products of the process production of FAME with use of fossil methanol, shows a fraction of non-renewable energy very low. For glycerol this value is 1.6% and for the methyl ester fraction of non-renewable energy depends on the type of molecule but always less than 2.4%. These findings could be used to devise correction criteria for the fiscal mechanisms being applied to these biofuels. ª 2011 Elsevier Ltd. All rights reserved. 1. Introduction The recent Directive 2009/28/EC, Renewable Energy Directive (RED), gives fresh impulse to the EU’s energy policy by further promoting the use of renewable energy sources. Biomass 1 is deemed critical to meet the directive’s targets. As in other directives, 2 biofuels 3 and bioliquids 4 are among the most prominent products, especially where electricity production and automotive applications are concerned. Among other provisions, the RED sets general sustainability criteria and defines the energy content of transport fuels (annex III). One of the best known biofuels is fatty acid methyl ester (FAME), or biodiesel. FAME is a methyl ester (ME) mixture produced from the reaction of vegetable oil glycerides with methanol, which derives from a fossil source. A by-product of the reaction, glycerol (GL), is also used for energy applications. Both molecules contain atoms from the methanol in the reagent and are therefore considered non-renewable. Other * Corresponding author. Tel.: þ39 071 2204297; fax: þ39 071 2204167. E-mail addresses: g.toscano@univpm.it (G. Toscano), g.riva@univpm.it (G. Riva), e.foppa@univpm.it (E. Foppa Pedretti), d.duca@univpm.it (D. Duca). 1 “The biodegradable fraction of products, waste and residues from agriculture (including vegetal and animal substances), forestry and related industries, as well as the biodegradable fraction of industrial and municipal waste” e Directive 2001/77/EC. 2 2001/77/EC, 2003/30/EC and 2003/96/EC. 3 Biofuels: liquid or gaseous fuel for transport produced from biomass. 4 Bioliquid: liquid fuel for energy purposes other than for transport, including electricity and heating and cooling, produced from biomass. Available at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 35 (2011) 3139 e3146 0961-9534/$ e see front matter ª 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.biombioe.2011.04.010