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Institute: search.filters.UBSInstitut.Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)Subject: search.filters.subject.333.7

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    Enhancement of the REMix energy system model : global renewable energy potentials, optimized power plant siting and scenario validation
    (2014) Stetter, Daniel; Müller-Steinhagen, Hans (Prof. Dr.-Ing. habil. DEng/Auckland)
    As electricity generation based on volatile renewable resources is subject to fluctuations, data with high temporal and spatial resolution on their availability is indispensable for integrating large shares of renewable capacities into energy infrastructures. The scope of the present doctoral thesis is to enhance the existing energy modelling environment REMix in terms of (i.) extending the geographic coverage of the potential assessment tool REMix-EnDaT from a European to a global scale, (ii.) adding a new plant siting optimization module REMix-PlaSMo, capable of assessing siting effects of renewable power plants on the portfolio output and (iii.) adding a new alternating current power transmission model between 30 European countries and CSP electricity imports from power plants located in North Africa and the Middle East via high voltage direct current links into the module REMix-OptiMo. With respect to the global potential assessment tool, a thorough investigation is carried out creating an hourly global inventory of the theoretical potentials of the major renewable resources solar irradiance, wind speed and river discharge at a spatial resolution of 0.45°x0.45°. A detailed global land use analysis determines eligible sites for the installation of renewable power plants. Detailed power plant models for PV, CSP, wind and hydro power allow for the assessment of power output, cost per kWh and respective full load hours taking into account the theoretical potentials, technological as well as economic data. The so-obtined tool REMix-EnDaT can be used as follows: First, as an assessment tool for arbitrary geographic locations, countries or world regions, deriving either site-specific or aggregated installable capacities, cost as well as full load hour potentials. Second, as a tool providing input data such as installable capacities and hourly renewable electricity generation for further assessments using the modules REMix-PlasMo and OptiMo. The plant siting tool REMix-PlaSMo yields results as to where the volatile power technologies photovoltaics and wind are to be located within a country in order to gain distinct effects on their aggregated power output. Three different modes are implemented: (a.) Optimized plant siting in order to obtain the cheapest generation cost, (b.) a minimization of the photovoltaic and wind portfolio output variance and (c.) a minimization of the residual load variance. The third fundamental addition to the REMix model is the amendment of the module REMix-OptiMo with a new power transmission model based on the DC load flow approximation. Moreover, electricity imports originating from concentrating solar power plants located in North Africa and the Middle East are now feasible. All of the new capabilities and extensions of REMix are employed in three case studies: In case study 1, using the module REMix-EnDaT, a global potential assessment is carried out for 10 OECD world regions, deriving installable capacities, cost and full load hours for PV, CSP, wind and hydro power. According to the latter, photovoltaics will represent the cheapest technology in 2050, an average of 1634 full load hours could lead to an electricity generation potential of some 5500 PWh. Although CSP also taps solar irradiance, restrictions in terms of suitable sites for erecting power plants are more severe. For that reason, the maximum potential amounts to some 1500 PWh. However, thermal energy storage can be used, which, according to this assessment, could lead to 5400 hours of full load operation. Onshore wind power could tap a potential of 717 PWh by 2050 with an average of 2200 full load hours while offshore, wind power plants could achieve a total power generation of 224 PWh with an average of 3000 full load hours. The electricity generation potential of hydro power exceeds 3 PWh, 4600 full load hours of operation are reached on average. In case study 2, using the module REMix-PlaSMo, an assessment for Morocco is carried out as to determine limits of volatile power generation in portfolios approaching full supply based on renewable power. The volatile generation technologies are strategically sited at specific locations to take advantage of available resources conditions. It could be shown that the cost optimal share of volatile power generation without considering storage or transmission grid extensions is one third. Moreover, the average power generation cost using a portfolio consisting of PV, CSP, wind and hydro power can be stabilized at about 10 €ct/kWh by the year 2050. In case study 3, using the module REMix-OptiMo, a validation of a TRANS-CSP scenario based upon high shares of renewable power generation is carried out. The optimization is conducted on an hourly basis using a least cost approach, thereby investigating if and how demand is met during each hour of the investigated year. It could be shown, that the assumed load can safely be met in all countries for each hour using the scenario's power plant portfolio. Furthermore, it was proven that dispatchable renewable power generation, in particular CSP imports to Europe, have a system stabilizing effect. Using the suggested concept, the utilization of the transfer capacities between countries would decrease until 2050.
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    Storage technologies for the electricity transition : an analysis of actors, actor perspectives and transition pathways in Germany
    (2020) Frey, Ulrich J.; Wassermann, Sandra; Deissenroth-Uhrig, Marc
    This article analyses actors in the storage niche during the German electricity transition. Thus, we develop a more differentiated understanding of actors and their storage activities. For that, we employ the analytical multi-level-perspective (MLP) framework to focus on interactions between old and new storage technologies. Using data from expert interviews, we investigate whether the storage pathway resembles any of the four ideal types of transition pathways for interactions between niche and regime. Through our interviews, we identify five types of actor in the storage market: Big 4 (EnBW, RWE, E.ON, Vattenfall), project developers, innovative municipal utilities, small rural municipal utilities and independent green electricity providers. For each actor, we analyse four main aspects (1) previous orientation and motivation, (2) structural strategies, (3) institutional strategies, and (4) product-related strategies. Parallel to the classification of actors, we also classify available storage technologies according to their primary field of application. We conclude that interactions between regime and niche actors are cooperative, but weak, and no specific actor type currently dominates the niche activities. Hence, applications in the storage niche are not yet ready for a larger market. In sum, our results point to a future system that is characterized by reconfiguration, not substitution or transformation of current market actors.
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    To prevent or promote grid expansion? : analyzing the future role of power transmission in the European energy system
    (2021) Cao, Karl-Kiên; Pregger, Thomas; Haas, Jannik; Lens, Hendrik
    Future energy supply systems must become more flexible than they are today to accommodate the significant contributions expected from intermittent renewable power sources. Although numerous studies on planning flexibility options have emerged over the last few years, the uncertainties related to model-based studies have left the literature lacking a proper understanding of the investment strategy needed to ensure robust power grid expansion. To address this issue, we focus herein on two important aspects of these uncertainties: the first is the relevance of various social preferences for the use of certain technologies, and the second is how the available approaches affect the flexibility options for power transmission in energy system models. To address these uncertainties, we analyze a host of scenarios. We use an energy system optimization model to plan the transition of Europe’s energy system. In addition to interacting with the heating and transport sectors, the model integrates power flows in three different ways: as a transport model, as a direct current power flow model, and as a linearized alternating current power flow model based on profiles of power transfer distribution factors. The results show that deploying transmission systems contribute significantly to system adequacy. If investments in new power transmission infrastructure are restricted - for example, because of social opposition - additional power generation and storage technologies are an alternative option to reach the necessary level of adequacy at 2% greater system costs. The share of power transmission in total system costs remains widely stable around 1.5%, even if cost assumptions or the approaches for modeling power flows are varied. Thus, the results indicate the importance of promoting investments in infrastructure projects that support pan-European power transmission. However, a wide range of possibilities exists to put this strategy into practice.
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    Bridging granularity gaps to decarbonize large‐scale energy systems : the case of power system planning
    (2021) Cao, Karl‐Kiên; Haas, Jannik; Sperber, Evelyn; Sasanpour, Shima; Sarfarazi, Seyedfarzad; Pregger, Thomas; Alaya, Oussama; Lens, Hendrik; Drauz, Simon R.; Kneiske, Tanja M.
    The comprehensive evaluation of strategies for decarbonizing large‐scale energy systems requires insights from many different perspectives. In energy systems analysis, optimization models are widely used for this purpose. However, they are limited in incorporating all crucial aspects of such a complex system to be sustainably transformed. Hence, they differ in terms of their spatial, temporal, technological, and economic perspective and either have a narrow focus with high resolution or a broad scope with little detail. Against this background, we introduce the so‐called granularity gaps and discuss two possibilities to address them: increasing the resolutions of the established optimization models, and the different kinds of model coupling. After laying out open challenges, we propose a novel framework to design power systems in particular. Our exemplary concept exploits the capabilities of power system optimization, transmission network simulation, distribution grid planning, and agent‐based simulation. This integrated framework can serve to study the energy transition with greater comprehensibility and may be a blueprint for similar multimodel analyses.
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    Regionale Energie- und Umweltanalyse für die Region Hochrhein-Bodensee : Kurzfassung
    (Waldshut-Tiengen : Regionalverband Hochrhein-Bodensee, 1989) Müller, Thomas; Boysen, Barbara; Fahl, Ulrich; Friedrich, Rainer; Kaltschmitt, Martin; Kuntze, Richard; Voß, Alfred; Giesecke, Jürgen; Jorde, Klaus; Voigt, C.
    In dem Gutachten wird auf der Grundlage der Erfassung des Energieverbrauchs und der Emissionen in der Region Hochrhein-Bodensee im Jahre 1986 ein Referenzszenario aufgebaut, in dem Annahmen über die Entwicklung des Energieverbrauchs und der Emissionen bis zum Jahre 2000 berechnet werden. Das Gutachten untersucht die Ausschöpfung weiterer Möglichkeiten der Energieeinsparung und die Nutzung weiterer Möglichkeiten zur Emissionsminderung in der Region. Eine umfangreiche und eingehende Untersuchung ist den Möglichkeiten der Verwendung regenerativer Energiequellen in der Region gewidmet. Insbesondere wird auch ein verstärkter Ausbau der Kraft-Wärme-Kopplung untersucht. Die wichtigsten Ergebnisse der Analyse liegen auch auf Gemeindebasis vor, so daß den Gemeinden in der Region wertvolle Handlungshinweise für ihre zukünftige Energiepolitik angeboten werden können. Der Regionalverband wird die Regionale Energie- und Umweltanalyse- in vollem Umfang veröffentlichen. Er schickt in dem vorliegenden Heft eine Zusammenfassung voraus, um erste Ergebnisse möglichst rasch zu veröffentlichen.
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    Integrative scenario assessment as a tool to support decisions in energy transition
    (2021) Kopfmüller, Jürgen; Weimer-Jehle, Wolfgang; Naegler, Tobias; Buchgeister, Jens; Bräutigam, Klaus-Rainer; Stelzer, Volker
    Energy scenarios represent a prominent tool to support energy system transitions towards sustainability. In order to better fulfil this role, two elements are widely missing in previous work on designing, analyzing, and using scenarios: First, a more systematic integration of social and socio-technical characteristics of energy systems in scenario design, and, second, a method to apply an accordingly enhanced set of indicators in scenario assessment. In this article, an integrative scenario assessment methodology is introduced that combines these two requirements. It consists of: (i) A model-based scenario analysis using techno-economic and ecological indicators; (ii) a non-model-based analysis using socio-technical indicators; (iii) an assessment of scenario performances with respect to pre-determined indicator targets; (iv) a normalization method to make the two types of results (model-based and non-model-based) comparable; (v) an approach to classify results to facilitate structured interpretation. The combination of these elements represents the added-value of this methodology. It is illustrated for selected indicators, and exemplary results are presented. Methodological challenges and remaining questions, e.g., regarding the analysis of non-model-based indicators, resource requirements, or the robustness of the methodology are pointed out and discussed. We consider this integrative methodology being a substantial improvement of previous scenario assessment methodologies.
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    Integrated multidimensional sustainability assessment of energy system transformation pathways
    (2021) Naegler, Tobias; Becker, Lisa; Buchgeister, Jens; Hauser, Wolfgang; Hottenroth, Heidi; Junne, Tobias; Lehr, Ulrike; Scheel, Oliver; Schmidt-Scheele, Ricarda; Simon, Sonja; Sutardhio, Claudia; Tietze, Ingela; Ulrich, Philip; Viere, Tobias; Weidlich, Anke
    Sustainable development embraces a broad spectrum of social, economic and ecological aspects. Thus, a sustainable transformation process of energy systems is inevitably multidimensional and needs to go beyond climate impact and cost considerations. An approach for an integrated and interdisciplinary sustainability assessment of energy system transformation pathways is presented here. It first integrates energy system modeling with a multidimensional impact assessment that focuses on life cycle-based environmental and macroeconomic impacts. Then, stakeholders’ preferences with respect to defined sustainability indicators are inquired, which are finally integrated into a comparative scenario evaluation through a multi-criteria decision analysis (MCDA), all in one consistent assessment framework. As an illustrative example, this holistic approach is applied to the sustainability assessment of ten different transformation strategies for Germany. Applying multi-criteria decision analysis reveals that both ambitious (80%) and highly ambitious (95%) carbon reduction scenarios can achieve top sustainability ranks, depending on the underlying energy transformation pathways and respective scores in other sustainability dimensions. Furthermore, this research highlights an increasingly dominant contribution of energy systems’ upstream chains on total environmental impacts, reveals rather small differences in macroeconomic effects between different scenarios and identifies the transition among societal segments and climate impact minimization as the most important stakeholder preferences.
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    Regionale Energie- und Umweltanalyse für die Region Hochrhein-Bodensee : Endbericht
    (1989) Müller, Thomas; Boysen, Barbara; Fahl, Ulrich; Friedrich, Rainer; Kaltschmitt, Martin; Kuntze, Richard; Voß, Alfred; Giesecke, Jürgen; Jorde, Klaus; Voigt, C.
    Ziel dieses Vorhabens ist es, für die Region Hochrhein-Bodensee eine fundierte Daten- und Informationsbasis sowie ein Analyseinstrumentarium zu erarbeiten, das rationale und effiziente Entscheidungen über die Verringerung der Luftschadstoffbelastung, den Ausbau der Energieversorgung und über Maßnahmen zur Energieeinsparung in diesem Gebiet ermöglicht.
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    Regionale Energie- und Umweltanalyse für die Region Hochrhein-Bodensee : Studie im Auftrag des Regionalverbandes Hochrhein-Bodensee
    (1990) Müller, Thomas; Boysen, Barbara; Fahl, Ulrich; Friedrich, Rainer; Kaltschmitt, Martin; Kuntze, Richard; Voß, Alfred; Giesecke, Jürgen; Jorde, Klaus; Voigt, C.
    Ziel dieses Vorhabens ist es, für die Region Hochrhein-Bodensee eine fundierte Daten- und Informationsbasis sowie ein Analyseinstrumentarium zu erarbeiten, das rationale und effiziente Entscheidungen über die Verringerung der Luftschadstoffbelastung, den Ausbau der Energieversorgung und über Maßnahmen zur Energieeinsparung in diesem Gebiet ermöglicht.
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    Projektabschlussbericht zum "Teilvorhaben Korrosionsverhalten" (FKZ 0325497B (MPA) + FKZ 0325497A (DLR)) des Verbundvorhabens "MS-Store - Flüssigsalzspeicher-Testanlage und neue Fluide"
    (2018) Kaesche, Stefanie; Rückle, Dagmar; Bauer, Thomas; Bonk, Alexander
    Ziel des Teilvorhabens „Korrosionsverhalten“ im Verbundprojekt MS-Store - Flüssigsalzspeicher-Testanlage und neue Fluide war es, Anforderungen an die zu verwendenden Werkstoffe, die durch hohe Temperaturen bei Energiespeichern in solarthermischen Kraftwerken auftreten, hinsichtlich des Korrosionsverhaltens zu untersuchen, um die Lebensdauer solcher Kraftwerke zu erhöhen, sowie substantielle wissenschaftliche Ergebnisse in diesem Anwendungsgebiet zu erhalten. Mittels Auslagerungsversuchen bei 560°C wurden die Abtragsraten für verschiedene Stähle in unterschiedlichen Nitratsalzmischungen in Abhängigkeit von der Auslagerungsdauer isotherm und zyklisch bestimmt. Im Anschluss wurden mittels diverser elektronenmikroskopischer und röntgenografischer Untersuchungsmethoden (FIB, REM, EDX; TEM; XRD) die Oxidschichtentwicklung und -beschaffenheit, die Phasenzusammensetzung der Oxidschicht, die Gefügestruktur des Grundwerkstoffs, sowie der erfolgte korrosive Angriff analysiert. Mittels elektrochemischer Prüfmethoden (OCP, IE, EIS) wurde das Korrosionsverhalten der Stähle in-situ bei Temperaturen zwischen 410 und 560°C und in Abhängigkeit der Reinheit der Salzschmelze analysiert, sowie die Stabilität der Oxidschichten evaluiert. Es zeigte sich eine eindeutige Überlegenheit der Korrosionsbeständigkeit der untersuchten Cr,Ni-Stähle gegenüber des hochwarmfesten Cr-Stahls, speziell in Salzschmelzen die Chloridgehalte ab 0,5 Gew.-% aufweisen. Weiterhin ließ sich eine eindeutige Abhängigkeit des Korrosionsverhaltens von der gewählten Temperatur nachweisen; die Beständigkeit ist bei 410°C deutlich höher, als bei 560°C. Die mehrlagigen Oxidschichten bestehen aus Cr,Fe-Mischoxiden, sowie reinen Cr-/Fe-Oxiden. Sie weisen eine hohe Porosität, sowie eine schlechte Haftung auf dem Grundmaterial auf. Nach langer Auslagerung entstehen zusätzlich Na,Fe-reiche Oxide. Im Grundmaterial bildeten sich durch Stickstoffeintrag aus der Salzschmelze an den Korngrenzen oder auch im kompletten Gefüge Gefügeveränderungen, in Form von Cr-Nitriden. Neuartige elektrochemische Untersuchungen in Nitratsalzschmelzen bei hohen Temperaturen wurden mittels elektrochemischer Impedanzspektroskopie (EIS) durchgeführt. Dabei wurde die Abhängigkeit des Korrosionsverhaltens von Temperatur, Salzreinheit und Beschaffenheit und Stabilität der Oxidschichten ermittelt. EIS eignet sich sehr gut, um schnell fundierte Aussagen über ein vorliegendes Korrosionssystem zu treffen und kann auch in anderen Schmelzen, sowie anderen Werkstoffen oder Parametern eingesetzt werden. Die quantitative Auswertung dieser Messmethode ist sehr komplex und benötigt anwendungsbasierte Weiterentwicklung. Dennoch konnte das Auftreten des Breakaway-Effektes mittels dieser Methodik bestätigt werden. Außerdem wurde die Tendenz von Chrom zur Lösung in der Salzschmelze festgestellt, sowie Änderungen im Nitrat/Nitrit-Verhältnis, bedingt durch Zersetzungsreaktionen der Salzschmelze beobachtet. Diese Effekte können zu veränderten Eigenschaften der Schmelze hinsichtlich ihrer Wärmespeicherkapazität, ihrer generellen Stabilität und ihrer Korrosivität führen. Die im Verlauf des Teilvorhabens gewonnenen Erkenntnisse erweitern den bisher in der Fachliteratur präsentierten Kenntnisstand des Korrosionsverhaltens von anwendungsrelevanten Stählen in Nitratsalzschmelzen deutlich. Sie ermöglichen eine gezielte Materialauswahl für Planer und Konstrukteure von solarthermischen Kraftwerken.