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The techno-economic potential of large-scale hydrogen storage in Germany for a climate-neutral energy system
No full textThe seasonal storage of natural gas is a recognized and reliable technology in the energy industry. Salt caverns are particularly suitable for storing alternative gaseous fuels such as hydrogen. Germany has a great technical potential for expanding its cavern storage capacity, which exceeds the expected demand for hydrogen many times. Regarding the projected long-term decline in natural gas use, the question arises as to whether existing caverns can meet future storage requirements. To this end, a techno-economic model is presented to meet electricity and hydrogen demand in a cost-optimal solution. This analysis focused on the utilization of hydrogen storage in terms of energy throughput and maximum storage capacity. To link the outcome of economic dispatch to the literature, the fundamental assumptions are based on comprehensive capacity expansion models. This study advances the state of the art by evaluating key input parameters of the future energy system. By conducting 192 model runs, the analysis revealed the range of uncertainty in terms of storage use. This indicates a strong dependence of the systemic and economic value of hydrogen storage on boundary conditions such as a consideration of dark doldrums, a flexible hydrogen demand profile, hydrogen import restrictions and a larger electrolyzer capacity. The uncertainty ranged from 0 to 67 TWhH2 for the storage capacity, with an average of 36.6 TWhH2 across all scenarios, and from 0 to 190 TWhH2 for the annual energy throughput. These results are significant for gas storage operators who derive transformation strategies and policymakers evaluating financial funding requirements
Herausforderungen der Blitzstoßspannungsprüfung an Leistungstransformatoren - Überblick über die CIGRE Arbeitsgruppe A2.63
No full textA New Diffusive Representation for Fractional Derivatives, Part I: Construction, Implementation and Numerical Examples
No full textDiffusive representations of fractional derivatives have proven to be useful tools in the construction of fast and memory efficient numerical methods for solving fractional differential equations. A common challenge in many of the known variants of this approach is that they require the numerical approximation of some integrals over an unbounded integral whose integrand decays rather slowly, which implies that their numerical handling is difficult and costly. We present a novel variant of such a diffusive representation. This form also requires the numerical approximation of an integral over an unbounded domain, but the integrand decays much faster. This property allows to use well established quadrature rules with much better convergence properties
Remarks on Alajos Alois Unger’s The Recapture of Győr 1598 (1840, Hungarian National Gallery) on the occasion of the 425th anniversary of the landmark event
Get PDFThe oil painting The Recapture of Győr 1598 (1840) is one of the two works by Alajos Alois Unger (Győr 1814-1848) in the collection of the Hungarian National Gallery since the 1970s. It depicts a landmark event in the Ottoman Wars that had an immense impact on the whole of Christian Europe, but outside of Hungary it has been largely forgotten. In the past two decades, considerable insight was gained into the obscure painter Unger, his works, family and networks. Playing-card maker Mátyás Mathias Unger the Elder was his father and Alajos Unger must have been the designer behind the family’s prized playing-cards. Unger was trained at the Imperial Academy of Arts in Vienna between 1833 and 1842, particularly under Leopold Kupelwieser and Johann Ender. All this new insight enables a more detailed interpretation of this history painting frequently displayed and its religious and political meaning. It is part of an unusual cycle of patriotic Hungarian artwork glorifying the House of Habsburg
Effekte von Dosishöhe und Instruktionsplausibilität auf Plazeboreaktionen gesunder Probanden
No full textPerceptions of relative group size and group status
No full textThe positive–negative asymmetry in social discrimination proposes a threshold for ingroup favouritism within the negative domain: in contrast to comparable studies dealing with in- and outgroup evaluations on positive attributes, ingroup favouritism does not occur when negative attributes are used. The present study focuses on two aspects of this threshold: it investigates processes, which may influence the absence of ingroup favouritism in the negative domain, and it tests ‘aggravating’ variables, which seem to be suficient to elicit ingroup favouritism even in the negative domain.
Results show that ingroup favouritism occurred within the negative domain when several aggravating conditions were included, namely high salience of size- and status- similarity between groups and high ingroup identification. Furthermore, subjects under minimal conditions tended to overestimate relative size as well as relative status of their ingroup. The perception of group members to belong to a high status majority is interpreted as a sufficient condition counteracting tendencies towards ingroup favouritism within the negative domain
Diffusive Representations for the Numerical Evaluation of Fractional Integrals
No full textDiffusive representations of fractional differential and integral operators can provide a convenient means to construct efficient numerical algorithms for their approximate evaluation. In the current literature, many different variants of such representations have been proposed. Concentrating on Riemann-Liouville integrals whose order is in (0,1), we here present a general approach that comprises most of these variants as special cases and that allows a detailed investigation of the analytic properties of each variant. The availability of this information allows to choose concrete numerical methods for handling the representations that exploit the specific properties, thus allowing to construct very efficient overall methods