Life cycle assessment of Brassica carinata biomass conversion to bioenergy and platform chemicals

The extraction, supply and use of fossil energy carriers and chemicals is a day-by-day increasingly critical issue, linked as it is to severe damages to environment and human health, not to talk of the shrinking availability of fossil fuels worldwide. Therefore, research on suitable alternatives to the extensive use of fossil-based fuels and chemicals is crucial: the potential of Brassica carinata, a non-food oil crop, to grow on marginal lands in Campania Region was investigated, focusing on the production of biodiesel from seeds and platform chemicals from agricultural and extraction residues via an innovative conversion route (so-called Biofine process) in a local industry. The aim of this paper is to evaluate the performance of such an agro-industrial system for biodiesel and bio-chemicals. A comparison with an equivalent system only producing biodiesel and thermal energy is also carried out. A Life Cycle Assessment (LCA) is performed by means of commercial LCA software (Simapro 7.3.0), investigating energy requirements and environmental impacts (global warming, acidification, abiotic depletion, human toxicity, eutrophication and photochemical oxidation). Results show that, in spite of claims of biomass-based "greenness", both systems still rely on large fractions of nonrenewable energy sources (around 90% of the total use) and mostly affect the same impact categories (abiotic depletion and global warming). The agricultural phase contributes to the total impact more than the industrial extraction and conversion steps, being the nitrogen fertilizers responsible for most of impacts of both systems. However, the conversion of lignocellulosic residues into chemicals instead of heat, conserves the structural quality of natural polymers in the form of marketable value added products (ethyl levulinate and formic acid), also translating into large energy savings compared to traditional chemical routes. (C) 2013 Elsevier Ltd. All rights reserved.