M. Gehrer, H. Seyfried, S. Staudacher

Possible processes to produce drop-in fuels focus on Fischer-Tropsch synthesis applied to oil-rich biomass (BtL), biocoal (CtL) and hydration of vegetable oil (HVO). Biofuels from microalgae are produced along four process lines: cultivation, harvest, extraction of raw material and conversion to fuel. This study deals with the life cycle assessment of the complete (partly theoretical) production chain of synthetic fuels (BtL, CtL and HVO) obtained from cultivation of a fresh water alga (Auxenochlorella protothecoides). Energy balance and environmental impact are analysed using GaBi software and data base. The main goal is to identify those factors, processes or production paths exerting the strongest impact, either environmentally or from the point of view of the energy balance. Using conventional sources of electric energy there is no economic competitive to conventional kerosene (NER = 1.2, CO2-equivalents per kg kerosene = 0.395 kg) among the different concepts of biofuel production from microalgae (Btl, CtL and HVO). However input from regenerative energy sources renders almost all CtL and HVO paths economic. Even under these conditions the BtL path remains energetically ineffective; its CO2-equivalents are better than those of kerosene only if hydroelectrically generated energy is used. In almost all cases the amount of primary energy demanded by laboratory cultivation is surprisingly high. We suspect that the high demand created by this initial production step might be an artefact of scaling when parameters of laboratory, pilot plant or theoretical processes are adapted to industrial dimensions.

Deutscher Luft- und Raumfahrtkongress 2014, Augsburg

Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2015

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

urn:nbn:de:101:1-2015020616246

Kraftstoffe, Ökobilanz

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06.02.2015