Ecological assessment of small-sized bio ethanol plants powered by renewable energy
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P2
Keywords: bioethanol, life cycle analysis, biofuels, value chain
Gwehenberger, G.*, Narodoslawsky M.*, Bauer, A.**, Amon T.**, , Liebmann, B.***, Pfeffer, M.***, Wukovits, W.***, Friedl, A.***
*Graz University of Technology, Inffeldgasse 21b, 8010 Graz, Austria
**University of Natural Resources and Applied Life Sciences, Peter-Jordan-Str. 82, 1090 Vienna, Austria
***Vienna University of Technology, Getreidemarkt 9/166, 1060 Vienna, Austria
Abstract
The trend towards biofuels as environmentally compatible alternatives is stipulated by the EU Biofuels Directive, and increases the importance of bioethanol. Bioethanol is a fermentation product of biomass containing glucose or starch, and is primarily produced in large-scale plants with capacities over 100.000 tons/year. Apart from large quantities of feedstock that cause considerable transportation costs and emissions, these conventional facilities are still powered by fossil fuels, hence challenging the sustainability of bioethanol production.
There is evidence that small-sized plants (1.000-10.000 t/y bioethanol) have more beneficial effect on regional ecologic as well as economic structures. Since small plants can be supplied with feedstock at local level, the position of farmers as energy producers is strengthened, while transportation efforts are abated. However, one crucial factor in facilities with low capacities is meeting its comparatively high specific energy requirements. In particular, the production of DDGS (Distillers’ Dried Grains with Solubles) by stillage drying accounts for a substantial amount of energy demand.
The alternative recycling of stillage in biogas fermenters doesn’t only save the energy of DDGS production, but also allows covering the heat and power demand of the bioethanol process by biogas instead of fossil fuels. Another possibility of supplying renewable thermal energy is the incineration of straw.
In this paper we compare the ecological impact of large scale conventional bioethanol plants with different combinations of small scale ethanol production processes with heat and power supplying facilities based on renewable resources. We show that these small scale plants have less ecological impact and are economical viable. The tool for these comparisons is the Sustainable Process Index (SPI), an ecological footprint method especially suited for the comparison of technical systems.
We gratefully acknowledge the support by “Energy Systems of Tomorrow”, a subprogram of the Federal Ministry of Transport, Innovation and Technology (BMVIT) in cooperation with the "Austrian Industrial Research Promotion Fund" (FFG).,
Presented Thursday 20, 13:30 to 14:40, in session EPIC-1: Poster Session (EPIC - Poster) - P2.
