Studies on the Integration of 1.5<sup>th</sup> and 2<sup>nd</sup> Generation Fuel Ethanol Production from Sweet Sorghum Stalks: Economic Performance, Energy Consumption and Carbon Emissions

Abstract

The paper investigates the feasibility of integrating 1.5th and 2nd generation (G) conversion technology for ethanol production from sweet sorghum stalks, in terms of economic performance, energy consumption and greenhouse gas emissions (3E). To that end, discriminants were developed for economic analysis to determine the conditions under which the transition from pure 1.5thG to the integration technology takes place. The paper also developed equations to calculate energy output/input ratio and carbon emissions during ethanol production processes. The results indicate that the main barrier of the development of integration technology is the high cost of 2ndG ethanol production. The residues from 2ndG production should be burned to supply energy for the ethanol plant, which is important to enhance the energy output/input ratio and to cut down carbon emissions. Compared with 1.5thG technology, the integration pathway brings about higher energy output/input ratio, but with slightly less amount of carbon emission reduction. However, the absolute amount of carbon emission reduction is still considerable. The estimation shows that the integration technology is promising in long term but infeasible under current conditions.