04 Fakultät Energie-, Verfahrens- und Biotechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/5
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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 Findings from measurements of the electric power demand of air compressors(2021) Hummel, Ulf; Radgen, Peter; Ülker, Sercan; Schelle, RalphThe compressed air electric ratio (CAER) describes the ratio of the real electric power demand to the nominal mechanical power of an air compressor. The CAER is an important indicator as the electric power demand of air compressors varies throughout its operation dependent on compressor technology, pressure ratio, and free air delivery. The nameplate power of the compressor drive motor is not sufficient for evaluating the electric power demand; therefore, the CAER plays an important role in assessing the electric operating power demand. In this paper, results from measurements of fixed speed and variable speed (VFD) compressors are presented with the analysis of key influencing factors of the CAER. The data show that the pressure ratio of operating pressure to the maximum design outlet pressure has the largest impact on the CAER. For VFD compressors, the CAER is represented as a linear function dependent on the respective load. Fixed and variable speed compressors’ CAERs are always dependent on the load condition. In idle condition, the CAER was measured to be 0.2. In full load condition with a pressure ratio of 0.6, the CAER averages at a value of 0.87, meaning a 90 kW compressor at 0.6 pressure ratio draws 78.3 kW electric power.Item Open Access Multi-criteria comparison of energy and environmental assessment approaches for the example of cooling towers(2022) Wenzel, Paula M.; Radgen, PeterCooling towers remove economically or technically unusable heat using considerable amounts of electricity and, in many cases, water. Several approaches, which vary in methodology, scope, and level of detail, are used for environmental evaluations of these cooling systems. Although the chosen approach has a significant impact on decisions made at the plant level, no methodology has yet been standardized for selecting the approach that best serves the objectives of the evaluation. Thus, this paper provides comparison criteria for the systematic selection of suitable evaluation methods for cooling towers and classifies how the methods score in this respect. These criteria, such as ‘life cycle thinking’, ‘inventoried physical quantities’, ‘temporal resolution’, ‘formalization’, and ‘data availability’, are grouped by overall evaluation objectives such as ‘thoroughness’, ‘scientific soundness’, and ‘usability’. Subsequently, these criteria were used to compare material flow analysis, energy analysis, environmental network analysis, life cycle inventory, life cycle assessment, environmental footprint methods, emergy analysis, exergy analysis, and the physical optimum method. In conclusion, material flow analysis is best suited for the analysis of cooling towers when impact assessment is not required; otherwise, life cycle assessment meets most of the defined criteria. Moreover, only exergy-based methods allow for the inclusion of volatile ambient conditions.Item Open Access Möglichkeiten der CO2-Emissionsminderung in der Elektrizitätsversorgung Baden-Württembergs(1992) Fahl, Ulrich; Fischedick, Manfred; Kaltschmitt, Martin; Voß, AlfredIn den aktuellen energiewirtschaftlichen Diskussionen werden die Möglichkeiten einer Verminderung der CO2-Emissionen insbesondere bei der Stromerzeugung sehr kontrovers diskutiert. Vor diesem Hintergrund ist es das Ziel dieses Beitrags, am Beispiel Baden-Württembergs die Möglichkeiten einer Reduktion der CO2-Emissionen unter Berücksichtigung der energiewirtschaftlichen und -politischen Rahmenbedingungen aufzuzeigen und das Minderungspotential sowie die Minderungskosten der Reduktionsmaßnahmen zu quantifizieren.Item Open Access Discussing the actual impact of optimizing cost and GHG emission minimal charging of electric vehicles in distributed energy systems(2021) Schulz, Maximilian; Hufendiek, KaiElectric vehicles represent a promising opportunity to achieve greenhouse gas (GHG) reduction targets in the transport sector. Integrating them comprehensively into the energy System requires smart control strategies for the charging processes. In this paper we concentrate on charging processes at the end users home. From the perspective of an end user, optimizing of charging electric vehicles might strive for different targets: cost minimization of power purchase for the individual household or - as proposed more often recently - minimization of GHG emissions. These targets are sometimes competing and cannot generally be achieved at the same time as the results show. In this paper, we present approaches of considering these targets by controlling charging processes at the end users home. We investigate the influence of differently designed optimizing charging strategies for this purpose, considering the electrical purchase cost as well as the GHG emissions and compare them with the conventional uncontrolled charging strategy using the example of a representative household of a single family. Therefore, we assumed a detailed trip profile of such a household equipped with a local generation and storage system at the same time. We implemented the mentioned strategies and compare the results concerning effects on annual GHG emissions and annual energy purchase costs of the household. Regarding GHG emissions we apply a recently proposed approach by other authors based on hourly emission factors. We discuss the effectivity of this approach and derive, that there is hardly no real impact on actual GHG emissions in the overall system. As incorporating this GHG target into the objective function increases cost, we appraise such theoretical GHG target therefore counterproductive. In conclusion, we would thus like to appeal for dynamic electricity prices for decentralised energy systems, leading at the same time to cost efficient charging of electric vehicles unfolding clear incentives for end users, which is GHG friendly at the end.Item Open Access CO2-Minderungspotential der Kraft-Wärme-Kopplung : ein Rückblick auf die Arbeiten der Enquete-Kommission(1992) Fahl, Ulrich; Pfeifer, Thomas; Voß, AlfredVon einem verstärkten Ausbau der Kraft-Wärme-Kopplung (KWK) wird ein wesentlicher Beitrag zur Bewältigung gegenwärtiger bzw. in naher Zukunft drohender Umwelt- und Klimaprobleme erwartet. Dies äußert sich auch darin, daß die KWK einen der Eckpfeiler des CO2-Minderungsprogramms der Bundesregierung bildet. Wie die folgende Analyse der Arbeiten zur KWK im Rahmen des Studienprogramms der Enquete-Kommission "Vorsorge zum Schutz der Erdatmosphäre" des 11. Deutschen Bundestages zeigt, sind aber trotz erheblichen Forschungsaufwandes in diesem Bereich noch sehr viele Fragen offen geblieben. Derartige Lücken könnten geschlossen werden, wenn das Potential der KWK zur CO2-Minderung über die Erzeugungsmöglichkeiten von Fern- und Nahwärme sowie der industriellen Eigenerzeugung zusammen mit den Wärmeanwendungen und -einsparmöglichkeiten ermittelt wird.Item Open Access C02-Minderungsmöglichkeiten im Kraftwerkssektor(1991) Fahl, Ulrich; Schaumann, Peter; Voß, AlfredUnter Klimatologen besteht weitgehende Übereinstimmung, daß die durch menschliche Tätigkeit freigesetzten Spurengase das Klima verändern. Unter diesen Spurengasen nimmt Kohlendioxid eine herausragende Rolle ein. Es gilt also, den CO2-Ausstoß zu verringern. Vorgestellt werden die im Kraftwerkssektor entstehenden CO2-Emissionen und mehrere Möglichkeiten der CO2-Minderung. Dabei werden auch die CO2-Minderungspotentiale in den fünf neuen Bundesländern analysiert.Item Open Access Exposure of individuals in Europe to air pollution and related health effects(2022) Li, Naixin; Friedrich, Rainer; Schieberle, ChristianAir pollutants, especially PM2.5 and NO2, are associated with adverse health impacts, as shown by numerous epidemiological studies. In these studies, the observed health impacts have been correlated with ambient concentrations, mainly taken from air pollution monitoring stations. However, individuals are harmed by the pollutants in the inhaled air at the places where they stay, and thus, the concentration of pollutants in the inhaled air is obviously a better indicator for health impacts than the ambient concentration at a monitoring station. Furthermore, the current method for estimating the occurrence of chronic diseases uses annual average concentrations as indicator. However, according to current hypotheses, chronic diseases, especially chronic mortality, develop through the exposure to pollutants over many years, maybe up to a full lifetime. Thus in this study, a methodology and a computer-aided probabilistic model system are described for calculating the exposure of a person to PM2.5 and NO2 over the whole lifetime where the person is characterized by attributes such as age, gender, place of residence and work as well as socioeconomic status. The model system contains a “life course trajectory model”, which estimates the course of the education and professional development for the past lifetime of a person, whose present socioeconomic status is known. Furthermore, a “time-activity model” estimates at which places (so-called micro-environments) a person with a certain socioeconomic status stayed and how long he stayed there within a certain year. The concentrations of air pollutants in indoor environments are calculated with a “mass-balance model”, the outdoor concentrations with “atmospheric models”. Finally, the results of these models are combined to estimate the annual average exposure for the life years of individuals and population subgroups. The exposure is then used to estimate and monetize health impacts. The exposures and health impacts for a number of population subgroups in Europe are presented. For instance, a European citizen, who was 70 years old in 2015, has been exposed to around 25 μg/m3 of PM2.5 during his lifetime above the age of 30, which is associated with a reduction of life expectancy of 13.4 days per year of exposure above 30.Item Open Access Cost-optimized heat and power supply for residential buildings : the cost-reducing effect of forming smart energy neighborhoods(2021) Bahret, Christoph; Eltrop, LudgerThe Clean Energy for all Europeans Package by the EU aims, among other things, to enable collective self-consumption for various forms of energy. This step towards more prosumer-based and decentralized energy systems comes at a time when energy planning at a neighborhood scale is on the rise in many countries. It is widely assumed that - from a prosumer’s cost-perspective - shared conversion and storage technologies supplying more than a single building can be advantageous. However, it is not clear whether this is the case generally or only under certain conditions. By analyzing idealized building clusters at different degrees of urbanization (DOU), a linear-optimization approach is used to study the cost difference between shared energy infrastructure (smart energy neighborhoods, SENs) and individually planned buildings. This procedure is carried out for various emission reduction targets. The results show, that with higher emission reduction targets the advantage of SENs increases within rural environments and can reach up to 16%. Nevertheless, there are constellations in which the share of energetic infrastructure among buildings does not lead to any economic advantages. For example, in the case of building clusters with less than four buildings, almost no cost advantage is found. The result of this study underlines the importance of energy system planning within the process of urban planning.