Einsatz von System Dynamics zur Modellierung der Szenarien-basierten Entwicklung des deutschen Biomethanmarktes

Biomethan aus lignin-reicher Biomasse (Holz, Stroh) wird durch thermochemische Vergasung hergestellt (Bio-SNG (biogenic synthetic natural gas)), während Biomethan aus lignin-armer (Energiepflanzen, tierische Exkremente, organischer Abfall,etc.) Biomasse durch anaerobe Vergärung hergestellt wird (Biomethan). Es kann zur Strom- und Wärmeversorgung beitragen, sowie als Kraftstoff im Verkehrssektor eingesetzt werden. In den genannten Sektoren kann Biomethan aufgrund der chemischen und physikalischen Äquivalenz zu fossilem Erdgas dieses substituieren und zum Klimaschutz beitragen. Die Anwendung von Erneuerbarem Methan als Option im Rahmen der Umgestaltung des auf fossilen Brennstoffen basierenden Energiesystems wird seit 2004 durch legislative Unterstützungsprogramme wie das Erneuerbare Energie Gesetz gefördert. Dies führte zur Entwicklung des weltweit größten Marktes für Biomethan. Bio-SNG ist bis heute nicht markt-relevant. Im Laufe des Überganges zu einem konsolidierten Markt für Erneuerbare-Energie-Produkte (bspw. Strom) wurden seit 2014 die Förderhöhen für diese reduziert. Als Folge stehen Produkte aus Erneuerbaren Energiequellen, wie bspw. Biomethan, in Deutschland vor einer ungewissen Zukunft, da die aktuellen Förderhöhen weder für einen weiteren Ausbau der Produktionskapazität ausreichen noch eine Erneuerung der Anlagen (nach Beendigung des Produktlebenszyklus) ermöglichen. Daher soll im Rahmen dieser Dissertation folgende Kernfrage beantwortet werden: • Unter welchen Randbedingungen kann sich Biomethan im Wettbewerb mit Erdgas auf dem deutschen Markt etablieren und welche Mengen an Biomethan werden dann produziert? Zur Beantwortung der Kernfrage wurde ein dynamisches Simulationsmodell anhand der Methode System Dynamics entwickelt. Auf Grundlage des Simulationsmodells wurden anschließend Szenarien definiert und simuliert. Als Untersuchungsraum wurde Deutschland im Zeitraum 2000 – 2035 gewählt. Die Simulationsergebnisse zeigen, dass eine Kombination aus Erhöhung des CO2-Preises des Europäischen Emissionshandelssystems und einer Förderung der Produktion von biogenem Flüssigerdgas potentiell in der Lage wäre, einen großen Anteil der aktuellen Biomethanproduktion unabhängig von staatlichen Fördersystemen aufrecht zu erhalten

An Illusional Nuclear Taboo: Mechanisms of Domestic Attitudinal Patterns for Extreme Methods of War

This dissertation studies public attitudes toward nuclear weapons. When do people become more willing to endorse a preemptive nuclear strike against a foreign country? Utilizing theoretical insights from international relations, comparative politics, and social psychology and original experimental survey data from Israel and the U.S., this dissertation aims to answer these questions. Influential strands of scholarship argue that both the public and political elites have internalized anti-nuclear norms. The critics, however, assert that the moral nuclear taboo lacks robustness. The dissertation joins this debate by offering a novel theoretical framework informed by terror management theory (TMT) and suggests that people are more likely to support extreme forms of warfare (e.g., nuclear strikes) when reminded of their own mortality. Thus, consequentialist factors, such as perceived utility, and psychological factors, such as moral foundations theory and TMT can be causal mechanism in the support for nuclear weapons. The findings support this argument as respondents who are treated with increased salience of their own mortality are more likely to support the use of nuclear weapons. Further, the results show that political ideology, threat perception, and religion are all significant factors in shaping individuals\u27 attitudes towards the use of nuclear weapons. Lastly, the work suggests that Israelis in particular tend to support hawkish national security options at the aggregate level. There is a positive effect of conflict events on Israelis\u27 support for hawkish policies. Overall, this dissertation makes a substantial contribution to our current understanding of public opinion on the use of nuclear weapons in a first strike and why nuclear weapons disarmament, elimination, and non-proliferation is deeply challenging

Biogas Upgrading: A Review of National Biomethane Strategies and Support Policies in Selected Countries

Bioenergy contributes significantly towards the share of renewable energies, in Europe and worldwide. Besides solid and liquid biofuels, gaseous biofuels, such as biogas or upgraded biogas (biomethane), are an established renewable fuel in Europe. Although many studies consider biomethane technologies, feedstock potentials, or sustainability issues, the literature on the required legislative framework for market introduction is limited. Therefore, this research aims at identifying the market and legislative framework conditions in the three leading biomethane markets in Europe and compare them to the framework conditions of the top six non-European biomethane markets. This study shows the global status and national differences in promoting this renewable energy carrier. For the cross-country comparison, a systematic and iterative literature review is conducted. The results show the top three European biomethane markets (Germany, United Kingdom, Sweden) and the six non-European biomethane markets (Brazil, Canada, China, Japan, South Korea, and the United States of America), pursuing different promotion approaches and framework conditions. Noteworthy cross-national findings are the role of state-level incentives, the tendency to utilise biomethane as vehicular fuel and the focus on residues and waste as feedstock for biomethane production. Presenting a cross-country comparison, this study supports cross-country learning for the promotion of renewable energies like biomethane and gives a pertinent overview of the work

Confounding effects of heart rate, breathing rate, and frontal fNIRS on interoception

Recent studies have established that cardiac and respiratory phases can modulate perception and related neural dynamics. While heart rate and respiratory sinus arrhythmia possibly affect interoception biomarkers, such as heartbeat-evoked potentials, the relative changes in heart rate and cardiorespiratory dynamics in interoceptive processes have not yet been investigated. In this study, we investigated the variation in heart and breathing rates, as well as higher functional dynamics including cardiorespiratory correlation and frontal hemodynamics measured with fNIRS, during a heartbeat counting task. To further investigate the functional physiology linked to changes in vagal activity caused by specific breathing rates, we performed the heartbeat counting task together with a controlled breathing rate task. The results demonstrate that focusing on heartbeats decreases breathing and heart rates in comparison, which may be part of the physiological mechanisms related to “listening” to the heart, the focus of attention, and self-awareness. Focusing on heartbeats was also observed to increase frontal connectivity, supporting the role of frontal structures in the neural monitoring of visceral inputs. However, cardiorespiratory correlation is affected by both heartbeats counting and controlled breathing tasks. Based on these results, we concluded that variations in heart and breathing rates are confounding factors in the assessment of interoceptive abilities and relative fluctuations in breathing and heart rates should be considered to be a mode of covariate measurement of interoceptive processes

Oscillatory brain responses to emotional stimuli are effects related to events rather than states

Emotional cues draw attention, thereby enabling enhanced processing. Electrophysiological brain research in humans suggests that increased gamma band activity and decreased alpha band activity over posterior brain areas is associated with the allocation of attention. However, emotional events can alternate quickly, like rapidly changing news items and it remains unknown whether the modulation of brain oscillations happens in a stimulus induced manner, changing with each individual stimulus, or whether the events lead to prolonged, state-like changes. To investigate this, we measured the electroencephalogram (EEG) during a passive viewing task (N = 32) while emotional pictures International Affective Picture System (IAPS) were presented in blocks containing either pleasant and neutral or unpleasant and neutral pictures. As predicted, we found decreased alpha and increased gamma power over posterior areas in response to unpleasant compared to pleasant pictures (and also compared to neutral pictures for gamma power). When testing the neutral pictures of the unpleasant and pleasant block against each other, we found no significant difference, which speaks to a stimulus induced effect of alpha and gamma power rather than a state effect. In addition, the inter-trial interval (ITI) between the pictures did not differ between the unpleasant and pleasant block either, corroborating this conclusion. Since emotional pictures can at the same time elicit a freezing-like response and we were interested in whether this freezing-like response co-occurs with enhanced attention, we also collected postural sway data. However, within this EEG-setup, postural analyses indicated no stimulus-related effects nor a correlation with EEG-data. We interpret the alpha and gamma band results as reflecting event-related attention toward unpleasant compared to pleasant (and neutral) pictures and discuss this finding in light of previous EEG research and in combination with behavioral research on threat-induced reductions in body sway (freezing-like response)

Gamma band directional interactions between basal forebrain and visual cortex during wake and sleep states

The basal forebrain (BF) is an important regulator of cortical excitability and responsivity to sensory stimuli, and plays a major role in wake-sleep regulation. While the impact of BF on cortical EEG or LFP signals has been extensively documented, surprisingly little is known about LFP activity within BF. Based on bilateral recordings from rats in their home cage, we describe endogenous LFP oscillations in the BF during quiet wakefulness, rapid eye movement (REM) and slow wave sleep (SWS) states. Using coherence and Granger causality methods, we characterize directional influences between BF and visual cortex (VC) during each of these states. We observed pronounced BF gamma activity particularly during wakefulness, as well as to a lesser extent during SWS and REM. During wakefulness, this BF gamma activity exerted a directional influence on VC that was associated with cortical excitation. During SWS but not REM, there was also a robust directional gamma band influence of BF on VC. In all three states, directional influence in the gamma band was only present in BF to VC direction and tended to be regulated specifically within each brain hemisphere. Locality of gamma band LFPs to the BF was confirmed by demonstration of phase locking of local spiking activity to the gamma cycle. We report novel aspects of endogenous BF LFP oscillations and their relationship to cortical LFP signals during sleep and wakefulness. We link our findings to known aspects of GABAergic BF networks that likely underlie gamma band LFP activations, and show that the Granger causality analyses can faithfully recapitulate many known attributes of these networks

Understanding the energy consumption and greenhouse gas emissions and the implication for achieving climate change mitigation targets

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Reasonable potential for GHG savings by anaerobic biomethane in Germany and UK derived from economic and ecological analyses

This study introduces a new approach to estimate biomethane market potential by analysing biogas markets and their relative environmental and economic advantages. This potential is then combined with greenhouse gas emission values for different feedstock shares (farm-fed and waste-fed systems) and different application share to determine the possible contribution of biomethane to national greenhouse gas emission saving goals. Markets that are considered are Germany and the UK being the biggest emitters of CO2eq in the European Union. The current use was compared with the scenarios (i) market projection, derived from literature study and (ii) reasonable potential, derived from environmental and economic calculations. The current market status is presented to show the past market development until the present date and associated greenhouse gas savings. Additionally the potential of biomethane to contribute to greenhouse gas emission savings is extensively described. Results indicate that the share of application in Germany is more environmental beneficial than the one in the UK achieving higher greenhouse gas savings at comparable feed-in level. In contrast, the UK has a higher share of waste-fed systems to produce biomethane. The use of biomethane in CHP plants achieves the highest GHG emission savings and if organic waste is used as feedstock the possible savings are even higher. With an increase of biomethane used in CHP plants and a decrease of biomethane used for direct heating the savings in the UK could increase up to 52%. Current savings of 2446 kt CO2eq (Germany) and 606 kt CO2eq (UK) can be extended to 4483 kt CO2eq (Germany) and 1443 kt CO2eq (UK) respectively. Scenario results were determined based on the environmental and economic advantageousness development of the existing biogas market. In this way positive future market development as well as improved shares of feedstock and application can contribute to further greenhouse gas emission savings of Germany and the UK

Autoregulation in resistance training : addressing the inconsistencies

Autoregulation is a process that is used to manipulate training based primarily on the measurement of an individual's performance or their perceived capability to perform. Despite being established as a training framework since the 1940s, there has been limited systematic research investigating its broad utility. Instead, researchers have focused on disparate practices that can be considered specific examples of the broader autoregulation training framework. A primary limitation of previous research includes inconsistent use of key terminology (e.g., adaptation, readiness, fatigue, and response) and associated ambiguity of how to implement different autoregulation strategies. Crucially, this ambiguity in terminology and failure to provide a holistic overview of autoregulation limits the synthesis of existing research findings and their dissemination to practitioners working in both performance and health contexts. Therefore, the purpose of the current review was threefold: first, we provide a broad overview of various autoregulation strategies and their development in both research and practice whilst highlighting the inconsistencies in definitions and terminology that currently exist. Second, we present an overarching conceptual framework that can be used to generate operational definitions and contextualise autoregulation within broader training theory. Finally, we show how previous definitions of autoregulation fit within the proposed framework and provide specific examples of how common practices may be viewed, highlighting their individual subtleties