Universität Stuttgart
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Item Open Access Die Auswirkungen einer Staustufe auf den Grundwasserhaushalt : Untersuchungen an einem numerischen Modell(1977) Mehlhorn, Hans; Kobus, Helmut; Lühr, Hans-PeterEs wird in zwei Teilen über die Auswirkungen einer Staustufe auf den Grundwasserhaushalt am Beispiel der geplanten Staustufe Neuburgweier berichtet. Teil I "Hydrologische und hydrogeologische Untersuchungen" (J. Armbruster, O. Huppmann und G. Strayle) ist in gwf-wasser/abwasser 118 (1977), H. 11, erschienen. Der vorliegende Beitrag ist der dazugehörige Teil II.Item Open Access Global potentials and costs of synfuels via Fischer-Tropsch process(2023) Buchenberg, Patrick; Addanki, Thushara; Franzmann, David; Winkler, Christoph; Lippkau, Felix; Hamacher, Thomas; Kuhn, Philipp; Heinrichs, Heidi; Blesl, MarkusThis paper presents the potentials and costs of synthetic fuels (synfuels) produced by renewable energy via PEM water electrolysis and the subsequent Fischer-Tropsch process for the years 2020, 2030, 2040, and 2050 in selected countries across the globe. The renewable energy potential was determined by the open-source tool pyGRETA and includes photovoltaic, onshore wind, and biomass. Carbon dioxide is obtained from biomass and the atmosphere by direct air capture. The potentials and costs were determined by aggregating minimal cost energy systems for each location on a state level. Each linear energy system was modelled and optimised by the optimisation framework urbs. The analysis focused on decentralised and off-grid synthetic fuels’ production. The transportation costs were roughly estimated based on the distance to the nearest maritime port for export. The distribution infrastructure was not considered since the already-existing infrastructure for fossil fuels can be easily adopted. The results showed that large amounts of synthetic fuels are available for EUR 110/MWh (USD 203/bbl) mainly in Africa, Central and South America, as well as Australia for 2050. This corresponds to a cost reduction of more than half compared to EUR 250/MWh (USD 461/bbl) in 2020. The synfuels’ potentials follow the photovoltaic potentials because of the corresponding low levelised cost of electricity. Batteries are in particular used for photovoltaic-dominant locations, and transportation costs are low compared to production costs.Item Open Access Energie und Klima: ist eine klimaverträgliche Energieversorgung erreichbar?(1991) Voß, AlfredUnter den Wissenschaftlern besteht weltweit Übereinstimmung, daß durch menschliche Tätigkeit freigesetzte Spurengase das Klima verändern. Unter diesen Spurengasen nimmt CO2 eine herausragende Rolle ein. Es gilt also, den CO2-Ausstoß zu verringern. Der Autor stellt die durch Energieumwandlungen entstehenden CO2-Emissionen vor und beschreibt mehrere Möglichkeiten einer CO2-Minderung. Hierbei geht er insbesondere auf die CO2-Reduktionsstrategien ein, wie sie für die Bundesrepublik Deutschland im Rahmen der Enquete-Kommission "Vorsorge zum Schutz der Erdatmosphäre" erarbeitet wurden.Item Open Access Energie bedeutet Lebensqualität : aus dem Vollen können wir nicht mehr schöpfen. T. 2(1980) Schmitz, Kurt; Voß, AlfredIn der ersten Folge dieses Berichtes schilderten die Autoren, wie Geschichte und Entwicklung der Menschheit mit der Möglichkeit der Energienutzung eng verknüpft sind und sich die heutige Weltenergiesituation darstellt. Nach einem Überblick über Energieverbrauch in der Bundesrepublik Deutschland wurden die Energievorräte und unsere Abhängigkeit von ihnen erläutert.Item Open Access Optimal design of experiments to improve the characterisation of atrazine degradation pathways in soil(2021) Chavez Rodriguez, Luciana; González‐Nicolás, Ana; Ingalls, Brian; Streck, Thilo; Nowak, Wolfgang; Xiao, Sinan; Pagel, HolgerContamination of soils with pesticides and their metabolites is a global environmental threat. Deciphering the complex process chains involved in pesticide degradation is a prerequisite for finding effective solution strategies. This study applies prospective optimal design (OD) of experiments to identify laboratory sampling strategies that allow model‐based discrimination of atrazine (AT) degradation pathways. We simulated virtual AT degradation experiments with a first‐order model that reflects a simple reaction chain of complete AT degradation. We added a set of Monod‐based model variants that consider more complex AT degradation pathways. Then, we applied an extended constraint‐based parameter search algorithm that produces Monte‐Carlo ensembles of realistic model outputs, in line with published experimental data. Differences between‐model ensembles were quantified with Bayesian model analysis using an energy distance metric. AT degradation pathways following first‐order reaction chains could be clearly distinguished from those predicted with Monod‐based models. As expected, including measurements of specific bacterial guilds improved model discrimination further. However, experimental designs considering measurements of AT metabolites were most informative, highlighting that environmental fate studies should prioritise measuring metabolites for elucidating active AT degradation pathways in soils. Our results suggest that applying model‐based prospective OD will maximise knowledge gains on soil systems from laboratory and field experiments.Item Open Access Regenerative Energiequellen im Spannungsfeld zwischen öffentlichen Erwartungen und technisch-ökonomischer Realität(1987) Voß, AlfredDer Verfasser macht den Versuch, den Stand der Entwicklung, die Entwicklungsperspektiven sowie die noch bestehenden Probleme derjenigen Techniken zur Nutzung regenerativer Energiequellen aufzuzeigen, die für die Bundesrepublik Deutschland von Bedeutung sein könnten. In Anbetracht der niedrigen Energiepreise kann festgestellt werden, daß trotz großer technischer Fortschritte keine der neuen Techniken zur Nutzung regenerativer Energiequellen heute schon wirtschaftlich konkurrenzfähig ist. Allerdings weist der Verfasser darauf hin, daß viele Techniken noch ein erhebliches Entwicklungspotential aufweisen. Die Alternative "Kernenergie oder Sonnenenergie" stellt sich somit heute nicht.Item Open Access Roadmap to neutrality - what foundational questions need answering to determine one’s ideal decarbonisation strategy(2022) Buettner, Stefan M.Considering increasingly ambitious pledges by countries and various forms of pressure from current international constellations, society, investors, and clients further up the supply chain, the question for companies is not so much whether to take decarbonisation action, but what action and by when. However, determining an ideal mix of measures to apply ‘decarbonisation efficiency’ requires more than knowledge of technically feasible measures and how to combine them to achieve the most economic outcome: In this paper, working in a ‘backcasting’ manner, the author describes seven aspects which heavily influence the composition of an ‘ideal mix’ that executive leadership needs to take a (strategic) position on. Contrary to previous studies, these aspects consider underlying motivations and span across (socio-)economic, technical, regulatory, strategic, corporate culture, and environmental factors and further underline the necessity of clarity of definitions. How these decisions influence the determination of the decarbonisation-efficient ideal mix of measures is further explored by providing concrete examples. Insights into the choices taken by German manufacturers regarding several of these aspects stem from about 850 responses to the ‘Energy Efficiency Index of German Industry’. Knowledge of the status quo, and clarity in definitions, objectives, time frames, and scope are key.Item Open Access Lab-scale investigation of palm shell char as tar reforming catalyst(2020) Chen, Yen-Hau; Schmid, Max; Chang, Chia-Chi; Chang, Ching-Yuan; Scheffknecht, GünterThis research investigated the application of palm shell char as a catalyst for the catalytic steam reforming of tar after the sorption enhanced gasification (SEG) process. The catalytic activities of palm shell char and metal-supported palm shell char were tested in a simulated SEG derived syngas with tar model compounds (i.e., toluene and naphthalene) at a concentration of 10 g m-3 NTP. The results indicated that palm shell char had an experimentally excellent catalytic activity for tar reforming with toluene and naphthalene conversions of 0.8 in a short residence time of 0.17 s at 900 °C. A theoretical residence time to reach the complete naphthalene conversion was 1.2 s at 900 °C for palm shell char, demonstrating a promising activity similar to wood char and straw char, but better than CaO. It was also found that potassium and iron-loaded palm shell chars exhibited much better catalytic activity than palm shell char, while the parallel reaction of gasification of K-loaded palm shell char influenced the conversion with its drastic mass loss. Moreover, contrary to CaO, palm shell char presented relatively low selectivity to benzene, and its spontaneous gasification generated extra syngas. In summary, the present study demonstrated that the low-cost material, palm shell char, can successfully be used as the tar-reforming catalyst after SEG process.Item Open Access Hydrologische und hydraulische Entwurfsgrundlagen und Bemessungsrichtlinien : Vorwort zum Sonderheft(1988) Kobus, HelmutAm 21. Juli 1987 fand an der Universität Stuttgart eine Vortragsveranstaltung statt, die sich mit den hydrologischen und hydraulischen Aspekten der Sicherheit von Stauanlagen befaßte. Das Sonderheft der WASSERWIRTSCHAFT enthält die Beiträge dieser Veranstaltung, welche vom Ministerium für Umwelt Baden-Württemberg gemeinsam mit dem Institut für Wasserbau der Universität Stuttgart ausgerichtet und vom Lehrstuhl für Technische Hydromechanik und Wasserbauliches Versuchswesen organisatorisch betreut wurde.