2,496 research outputs found
Braucht Europa Atomkraft?
Im Energiemix, den die Bundesregierung in ihrem Energiekonzept vorsieht, sollen in Zukunft die erneuerbaren Energien den Hauptanteil übernehmen. Wie muss eine langfristige Strategie für die zukünftige Energieversorgung aussehen, und welche Rolle spielt dabei die Atomkraft? Nach Ansicht von Franz Mayinger, Technische Universität München, ist ein Verzicht auf Kernenergie weder ökologisch sinnvoll noch wirtschaftlich vertretbar. Europa stehe in Wettbewerb mit den aufstrebenden asiatischen Ländern und in zunehmendem Maße auch mit Südamerika und brauche, insbesondere für moderne effiziente Produktionsprozesse, eine zuverlässige und auf Dauer bezahlbare Stromversorgung. Wirtschaftliche Zwänge, aber auch ein angemessener Wohlstand der Bevölkerung erforderten für Europa den Erhalt und den weiteren Ausbau der Kernenergie, insbesondere dann, wenn man den Klimawandel ernst nehme und die CO2-Emissionen vermindern müsse. Für Thomas Hamacher, Technische Universität München, lautet die eigentliche Frage nicht, ob man im Jahr 2050 noch Kernenergie brauchen wird, sondern wie eine Kernenergie aussehen muss, die im Jahr 2050 als wesentlicher Baustein einer nachhaltigen Energiewirtschaft gelten kann, und was heute an Forschungsvorhaben angestoßen werden muss, damit dies in 40–50 Jahren realisiert werden kann. Seiner Meinung nach solle durch weitere intensive Forschung versucht werden, die Kernenergie so weiterzuentwickeln, dass sie mit strengen Kriterien der Nachhaltigkeit vereinbar ist. Fusionskraftwerke versprechen dabei eine Überwindung der oben genannten Nachhaltigkeitsdefizite. Die Brennstoffe stehen in ausreichender Menge zur Verfügung. Die Sicherheit während des Betriebs ist durch die prinzipiellen Eigenschaften – nicht zuletzt die niedrige Leistungsdichte – gewährleistet. Langelebige radioaktive Abfälle entstehen nicht.Kernenergie, Energieversorgung, Regenerative Energie, Klimaschutz, Elektrizitätswirtschaft, Deutschland, EU-Staaten
Perspectives for Electricity Generation from Renewable Energy Sources in the South Caucasus Region
Renewable energy sources are sustainable, domestic and allow for diversification of resources. Given their availability and economic feasibility, they could contribute toward a reliable electricity supply for the South Caucasus region. Based on annual generation time series derived from weather data for the period 2000-2012, we analyse the availability and economic feasibility of wind power and solar photovoltaics in Armenia, Azerbaijan and Georgia. Our analysis demonstrates that electricity generation from wind and solar power is currently not economically feasible in any of the three countries. However, we demonstrate that the attractiveness of renewable energy sources improves significantly in the future if investment costs and the cost of capital can be reduced. We conclude by discussing possible benefits of an early introduction of renewable energy sources in the electricity supply of the South Caucasus region
Optimization-based framework for low-voltage grid reinforcement assessment under various levels of flexibility and coordination
The rapid electrification of residential heating and mobility sectors is
expected to drive the existing distribution grid assets beyond their planned
operating conditions. This change will also reveal new potentials through
sector coupling, flexibilities, and the local exchange of decentralized
generation. This paper thus presents an optimization framework for multi-modal
energy systems at the low voltage (LV) distribution grid level. In this, we
focus on the reinforcement requirements of the grid and the techno-economic
assessment of flexibility components and coordination between agents. By
employing a multi-level approach, computational complexity is reduced, and
various levels of coordination and flexibilities are implemented. We conclude
the work with a case study for a representative rural grid in Germany, in which
we observe high economic potential in the flexible operation of buildings,
majorly thanks to better integration of photovoltaics. Across all paradigms
barring a best-case benchmark, grid reinforcement based on a mix of passive and
active measures was necessary. A synergy effect is observed between
flexibilities and coordination, as their combination reduces the peaks to the
extent of completely avoiding grid reinforcement. The presented framework can
be applied with a wide range of grid and component types to outline the broad
landscape of future LV distribution grids
SPIKE: Secure and Private Investigation of the Kidney Exchange problem
Background: The kidney exchange problem (KEP) addresses the matching of
patients in need for a replacement organ with compatible living donors. Ideally
many medical institutions should participate in a matching program to increase
the chance for successful matches. However, to fulfill legal requirements
current systems use complicated policy-based data protection mechanisms that
effectively exclude smaller medical facilities to participate. Employing secure
multi-party computation (MPC) techniques provides a technical way to satisfy
data protection requirements for highly sensitive personal health information
while simultaneously reducing the regulatory burdens.
Results: We have designed, implemented, and benchmarked SPIKE, a secure
MPC-based privacy-preserving KEP which computes a solution by finding matching
donor-recipient pairs in a graph structure. SPIKE matches 40 pairs in cycles of
length 2 in less than 4 minutes and outperforms the previous state-of-the-art
protocol by a factor of 400x in runtime while providing medically more robust
solutions.
Conclusions: We show how to solve the KEP in a robust and privacy-preserving
manner achieving practical performance. The usage of MPC techniques fulfills
many data protection requirements on a technical level, allowing smaller health
care providers to directly participate in a kidney exchange with reduced legal
processes.Comment: 26 pages, 6 figure
Evaluation of Hierarchical, Multi-Agent, Community-Based, Local Energy Markets Based on Key Performance Indicators
In recent years, local energy markets (LEMs) have been introduced to empower end-customers within energy communities at the distribution level of the power system, in order to be able to trade their energy locally in a competitive and fair environment. However, there is still some challenge with regard to the most efficient approach in organising the LEMs for the electricity exchange between consumers and prosumers while ensuring that they are responsible for their electricity-related choices, and concerning which LEM model is suitable for which prosumer or consumer type. This paper presents a hierarchical model for the organisation of agent-based local energy markets. According to the proposed model, prosumers and consumers are enabled to transact electricity within the local energy community and with the grid in a coordinated manner to ensure technical and economic benefits for the LEM’s agents. The model is implemented in a software tool called Grid Singularity Exchange (GSyE), and it is verified in a real German energy community case study. The simulation results demonstrate that trading electricity within the LEM offers economic and technical benefits compared to transacting with the up-stream grid. This can further lead to the decarbonization of the power system sector. Furthermore, we propose two models for LEMs consisting of multi-layer and single-layer hierarchical agent-based structures. According to our study, the multi-layer hierarchical model is more profitable for household prosumers as compared to trading within the single-layer hierarchical LEM. However, the single-layer LEM is more be beneficial for industrial prosumers.© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed
Multifacility Location Problems with Tree Structure and Finite Dominating Sets
Multifacility location problems arise in many real world applications. Often, the facilities can only be placed in feasible regions such as development or industrial areas. In this paper we show the existence of a finite dominating set (FDS) for the planar multifacility location problem with polyhedral gauges as distance functions, and polyhedral feasible regions, if the interacting facilities form a tree. As application we show how to solve the planar 2-hub location problem in polynomial time. This approach will yield an ε-approximation for the euclidean norm case polynomial in the input data and 1/ε
Stereoscopic space map – semi-immersive configuration of 3Dstereoscopic tours in multi-display environments
Although large-scale stereoscopic 3D environments like CAVEs are a favorable location for group presentations, the perspective projection and stereoscopic optimization usually follows a navigator-centric approach. Therefore, these presentations are usually accompanied by strong side-effects, such as motion sickness which is often caused by a disturbed stereoscopic vision. The reason is that the stereoscopic visualization is usually optimized for the only head-tracked person in the CAVE – the navigator – ignoring the needs of the real target group – the audience.
To overcome this misconception, this work proposes an alternative to the head tracking-based stereoscopic effect optimization. By using an interactive virtual overview map in 3D, the pre-tour and on-tour configuration of the stereoscopic effect is provided, partly utilizing our previously published interactive projection plane approach. This Stereoscopic Space Map is visualized by the zSpace 200®, whereas the virtual world is shown on a panoramic 330° CAVE2TM.
A pilot expert study with eight participants was conducted using pre-configured tours through 3D models. The comparison of the manual and automatic stereoscopic adjustment showed that the proposed approach is an appropriate alternative to the nowadays commonly used head tracking-based stereoscopic adjustment
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