Methodology for the design and comparison of optimal production configurations of first and first and second generation ethanol with power Rami Bechara a,⇑ , Adrien Gomez a , Valérie Saint-Antonin b , Jean-Marc Schweitzer a , François Maréchal c a Process Modeling and Design, IFPEN, Insitut Français du Pétrole et des Energies Nouvelles, Rond Point de l’Echangeur de Solaize, Lyon, France b Economics and Information Watch and Management, IFPEN, 1-4 Avenue du Bois Préau, 92852 Rueil-Malmaison, France c Industrial Process and Energy Systems Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL Valais Wallis, Rue de l’Industrie 17, CH-1951 Sion, Switzerland highlights  1st generation (1G) ethanol and power vs. 1G and 2G ethanol and power processes.  Application of simulation-optimiza tion-selection method for optimal process design.  Optimization results have efficiencies, costs and utilities better than literature.  2G ethanol competitive only for 2G ethanol prices 2–4 times higher than normal.  Similar design for two processes saves evaporation, utilities, hydrolysis and drying. graphical abstract article info Article history: Received 16 March 2016 Received in revised form 25 August 2016 Accepted 26 September 2016 Keywords: Optimal process design methodology Process modeling Second generation vs. power production Multi-objective optimization NPV maximization Minimum cellulosic ethanol selling price abstract This article applies a systematic methodology to the optimization and comparison of two sugarcane con- version processes of great potential: the production of first generation ethanol and electricity in an inte- grated distillery and cogeneration plant (1G+COGEN), and the production of first and second generation ethanol and electricity in an integrated distillery, hydrolysis and cogeneration plant (1G+2G+COGEN). The employed method consisted of rigorous process simulation, heat integration, thermo-economic eval- uation, bi-objective, exergy efficiency vs. capital cost, optimization and selection via profitability maxi- mization. The exergy efficiency of optimal 1G+COGEN and 1G+2G+COGEN configurations ranged from 37.5% to 41.7% and from 41.8% and 44.42% respectively. Fixed capital increased with exergy efficiency from USD 155 million to USD 209 million and from USD 252 million to USD 393 million respectively. Ethanol production rate averaged at 81.4 L/ton cane (TC) for 1G+COGEN configurations whereas it increased with exergy efficiency to 106 L/TC for 1G+2G+COGEN schemes. Electricity production increased for the first from 122 to 188 kW h/TC and decreased for the second from 180 kW h/TC to 92 kW h/TC. 1G +COGEN schemes presented higher NPV values with a minimum difference of $45 million than 1G+2G +COGEN schemes, with the maximum at an exergy efficiency of 40.65%. Equal profitability was obtained when second generation ethanol selling prices were set at values two to four times greater than the stan- dard, with the most profitable 1G+2G+COGEN configuration having the greater efficiency at 44.4%. A comparison of the two schemes displayed key similarities relating to vapor bleeding, heat integration, http://dx.doi.org/10.1016/j.apenergy.2016.09.100 0306-2619/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: rami.bechara@etu.univ-lyon1.fr (R. Bechara), adrien.gomez@ ifpen.fr (A. Gomez), valerie.saint-antonin@ifpen.fr (V. Saint-Antonin), jean-marc. schweitzer@ifpen.fr (J.-M. Schweitzer), francois.marechal@epfl.ch (F. Maréchal). Applied Energy 184 (2016) 247–265 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy