Jauch, C. . (2021). Grid Services and Stress Reduction with a Flywheel in the Rotor of a Wind Turbine. Energies, 14. http://doi.org/10.3390/en14092556
Abstract
Wind power penetration increases in most grids and the sizes of wind turbines increase. This leads to increasingly tough requirements, which are imposed on wind turbines, both from the grid as well as from economics. Some of these partially contradictory requirements can only be satisfied with additional control mechanisms in the wind turbines. In this paper, such a mechanism, i.e., a hydraulic–pneumatic flywheel system in the rotor of a wind turbine, is discussed. This flywheel system supports a wind turbine in providing grid services such as steadying the power infeed, fast frequency response, continuous inertia provision, power system stabilization, and low voltage ride-through. In addition, it can help mitigate the stress on the mechanical structure of a wind turbine, which results from varying operating points, imbalances in the rotor, gravitation that acts on the blades, in-plane vibrations, and emergency braking. The study presented in this paper is based on simulations of a publicly available reference wind turbine. Both the rotor blade design as well as the design of the flywheel system are as previously published. It is discussed how the aforementioned grid services and the stress reduction mechanisms can be combined. Finally, it is concluded that such a flywheel system broadens the range of control mechanisms of a wind turbine substantially, which is beneficial for the grid as well as for the wind turbine itself.
Chirvi, M. ., Huber, H.-P. ., & Schneider, C. . (2021). Biased Preferences for Wealth Taxation: The Case of Misperceived Tax Burden Consequences. TRR 266 Working Paper Series.
Abstract
The individual capacity to form personal preferences constitutes an essential element of thedemocratic process. At the same time, policies with far-reaching consequences often require profound expertise. Taxation is such an example. Due to its complex character, bounded rationality might induce biases causing other outcomes than intended. This paper quantifies shifts in stated preferences for wealth taxation caused by misperceived burden consequences of commonly politically discussed tax parameters: tax allowances and tax rates. For this, we conducted a randomized survey experiment with over 1,200 respondents in Germany. In a 2 by 2 design, our respondents were randomly selected to indicate both their preferred tax allowance and tax rate for either a yearly or a one-time wealth tax. Our treatment group was provided with easy-to-understand information on the resulting effective lifetime tax burden for the respective instrument. We find the preferred effective tax rate to drop by almost 15 percentage points for a yearly wealth tax if our participants are fully informed, whereas we do not find this effect for the one-time wealth tax. In terms of informed preferences our respondents preferthe yearly wealth tax over a one time wealth tax if misperceptions are resolved: the preferred effective tax burden of a yearly wealth tax is about 25 percentage points higher (40.0% vs.15.2%). While not being able to fully explain the source of this difference, we argue that both the total burden as well as the reasonability of single payments might be factors that form preferences for tax parameters.
Boysen, C. ., Kaldemeyer, C. ., Sadat, F. ., Tuschy, I. ., Witte, F. ., Bauer, S. ., & Dahmke, A. . (2021). Integration unterirdischer Speichertechnologien in die Energiesystemtransformation am Beispiel des Modellgebietes Schleswig-Holstein - ANGUS II : Schlussbericht zum Verbundvorhaben Teilprojekt Simulation energietechnischer Einzelanlagen. Hochschule Flensburg. Abgerufen von https://www.tib.eu/de/suchen/id/TIBKAT%3A1798315475
Oelze, N. ., Simasiku, B. M., & Jackie, L. L. (2021). Namibian State of Logistics 2020 Report. Windhoek: Namibian-German Centre for Logistics. Abgerufen von https://www.giz.de/en/downloads/NGCL_Namibia-State-of-Logistics_Report2020-1.pdf
Abstract
This document has been prepared to summarise the findings of a study carried out by the Namibian-German Centre for Logistics into the current state of logistics in Namibia during the period from 2018 to 2020 and the impact of the Covid-19 pandemic on the industry. It updates studies carried into Namibian logistics in 2012 and 2018. The study has been undertaken by the research team on an wholly independent basis making use of contemporary data available in the public domain and surveys conducted by the team. It reflects the opinions of the authors based of review and analysis of the available evidence.
Zhang, J. ., Zeng, R. ., & Labes, A. . (2021). Marine microbial-derived molecules and their potential medical and cosmetic applications ). Frontiers in Microbiology, 12, 1965. http://doi.org/10.3389/FMICB.2021.706152
Chirvi, M. . (2021). Arbeiten Frauen aufgrund des Ehegattensplittings weniger? — Eine empirische Untersuchung für Deutschland. Steuer Und Wirtschaft, 98(2). http://doi.org/10.9785/stuw-2021-980207
Abstract
Der Beitrag soll zur Klärung der Frage beitragen, ob das Ehegattensplitting, wie vielfach behauptet wird, einen negativen Einfluss auf das Arbeitsverhalten verheirateter Frauen hat. Hierzu kommt für Deutschland erstmals ein von Quasi-Experimenten inspirierter Ansatz zum Einsatz, bei dem anhand des allgemeinen Effekts der Heirat auf das Erwerbsverhalten der heiratenden Frauen die Wirkung des Ehegattensplittings geschätzt wird. Die Veränderung des Arbeitsverhaltens heiratender Frauen wird dabei der Veränderung bei jenen Frauen gegenübergestellt, die im gleichen Zeitraum weiterhin mit ihrem festen Partner zusammenleben, ohne zu heiraten (Kontrollgruppe). Die Ergebnisse sprechen eindeutig gegen einen unmittelbaren negativen Effekt des Ehegattensplittings auf das Erwerbsverhalten von Frauen. Jedoch reduzieren heiratende und zeitgleich ein Kind bekommende Frauen ihre Erwerbstätigkeit stärker als gebärende Frauen in der Kontrollgruppe. In Folge einer lediglich teilweisen Abschaffung des Ehegattensplittings, die in den Entwürfen zu Parteiprogrammen zur Bundestagswahl 2021 teilweise gefordert wird, sind sogar noch geringere Effekte auf das Arbeitsverhalten zu erwarten.
Irshad, M. ., Britto, R. ., & Petersen, K. . (2021). Adapting Behavior Driven Development (BDD) for large-scale software systems. Journal of Systems and Software, 177, 110944.