1,720,964 research outputs found
Do voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying their impact (Supplementary Material)
No full textThese files contain the supplementary material for: "Do voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying their impact".
The input data can be found here:
Partial C&I load
New hydrogen load
Riepin et al. 2022
Xu et al. 2022
Ricks et al. 2023
Zeyen et al. 2022
Data source
supplied by author
zenodo.6344910
zenodo.7442511
zenodo.745744
Does the purchase of voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying the impact
No full text<p>These files contain the supplementary material for: "Does the purchase of voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying the impact".</p>
<p>The input data can be found here:</p>
<table>
<tbody>
<tr>
<td>
<p> </p>
</td>
<td>
<p><strong>Partial C&I load</strong></p>
</td>
<td>
<p><strong>New hydrogen load</strong></p>
</td>
</tr>
<tr>
<td> </td>
<td>
<p><strong>Riepin et al. 2022</strong></p>
</td>
<td>
<p><strong>Xu et al. 2022</strong></p>
<p><strong>Xu et al. 2023</strong></p>
</td>
<td>
<p><strong>Ricks et al. 2023</strong></p>
</td>
<td>
<p><strong>Zeyen et al. 2022</strong></p>
</td>
</tr>
<tr>
<td>
<p><strong>Data source</strong></p>
</td>
<td>
<p>supplied by author</p>
</td>
<td>
<p>zenodo.6344910</p>
<p>zenodo.8302738</p>
</td>
<td>
<p>zenodo.7442511</p>
</td>
<td>
<p>zenodo.7457441</p>
</td>
</tr>
</tbody>
</table>
Does the purchase of voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying the impact
No full text<p>These files contain the supplementary material for: "Does the purchase of voluntary renewable energy certificates lead to emission reductions? A review of studies quantifying the impact".</p>
<p>The input data can be found here:</p>
<table>
<tbody>
<tr>
<td>
<p> </p>
</td>
<td>
<p><strong>Partial C&I load</strong></p>
</td>
<td>
<p><strong>New hydrogen load</strong></p>
</td>
</tr>
<tr>
<td> </td>
<td>
<p><strong>Riepin et al. 2022</strong></p>
</td>
<td>
<p><strong>Xu et al. 2022</strong></p>
<p><strong>Xu et al. 2023</strong></p>
</td>
<td>
<p><strong>Ricks et al. 2023</strong></p>
</td>
<td>
<p><strong>Zeyen et al. 2022</strong></p>
</td>
</tr>
<tr>
<td>
<p><strong>Data source</strong></p>
</td>
<td>
<p>supplied by author</p>
</td>
<td>
<p>zenodo.6344910</p>
<p>zenodo.8302738</p>
</td>
<td>
<p>zenodo.7442511</p>
</td>
<td>
<p>zenodo.7457441</p>
</td>
</tr>
</tbody>
</table>
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
An Optimal Peer-to-Peer Market Considering Modulating Heat Pumps and Photovoltaic Systems under the German Levy Regime
Full text linkThe European Commission calls for more small-scale renewable energy producers to actively participate in the energy value chain. In this study, we model an illustrative peer-to-peer (P2P) market with tariffs based on the reservation prices of market participants under the German levy regime. The study is conducted by modeling representative residential buildings with home energy management systems, modulating heat pumps, and photovoltaics, in combination with electrical and thermal storage systems. The resulting mixed-integer linear program is solved over the course of a year, using a rolling horizon approach with a time resolution of one hour. By analyzing the cost- and discomfort-minimizing behavior of the market participants, we evaluate the current levy regime and propose two additional designs. We find that in the current case, a P2P market is not economically viable. Based on feed-in tariffs (FiT) and levies no agreeable market price can be found. With no FiT or reduced levies, all participants benefit from the P2P market. The market split—where each household sources their energy from—is altered only little by the specific details of the market design when staying in the agreeable price range. As prosumagers do not consume on the P2P market, they benefit only marginally from the reduced levies—consumers are most affected. Adjusting the regime could be a measure to rebalance the distribution of renewable energy benefits towards consumers in order to foster social cohesion. Our input data and the model written in the Julia JuMP programming language are available in an open-source format.TU Berlin, Open-Access-Mittel – 202
Optimierung, Vorschriften und Regelungen, und Lernsysteme
No full textBuildings are one of the main drivers of global energy consumption and CO2 emissions. Efficient home energy management systems and residential sector coupling play a key role in supporting the energy transition in this sector. At the same time, the European Commission calls for more small-scale renewable energy producers to actively participate in the energy value chain.
In my first study, I analyze the structural properties associated with the optimal control of a home energy management system and the effects of common technological configurations and modeling objectives. I model a smart home energy management system (SHEMS) using a model predictive control (MPC) approach formulated as a mixed-integer linear program (MILP). I determine the value of information evaluating different forecast horizons.
In my second study, I model an illustrative peer-to-peer (P2P) market with tariff s based on the reservation prices of market participants under the current German levy regime. By analyzing the cost- and discomfort-minimizing behavior of the market participants, I evaluate the current levy regime and propose two additional market designs.
In my third study, I analyze the potential of deep reinforcement learning (DRL) to control SHEMS. The algorithm is model-free, it does not know the physical building model, and only considers information currently available. The algorithm learns autonomously based on the feedback signal generated by a SHEMS DRL environment.
I conduct all studies by modeling a representative residential building with a modulating air-sourced heat pump, a photovoltaic (PV) system, a battery energy storage system (BESS), and thermal storage systems for floor heating and hot water supply. In addition, I allow grid feed-in with a fixed compensation and consider user comfort.
In my first numerical analysis, I find that the BESS is the essential building block for improving self-sufficiency. However, in order to use the PV surplus efficiently grid feed-in is necessary. Based on optimal control and considering seasonal effects, the dominant order of demand fulfillment and the target states of charge for the storage systems are derived.
I find that the solution time can be significantly reduced, losing an acceptable amount of profit, by optimizing for self-sufficiency instead of profit maximization, or by using a rolling horizon approach.
In my second numerical analysis, I find that using the current levy regime in Germany, a P2P market is not economically viable. Based on feed-in tariff s (FiTs) and high levies no agreeable market price can be found. With no FiT or reduced levies, all participants benefit from the P2P market. As prosumagers do not consume on the P2P market, they are only marginally affected by the reduced levies—consumers benefit most. Adjusting the regime towards consumers could result in a fairer allocation of the profits of the energy transition.
In my third numerical analysis, I benchmark my results based on the deep deterministic policy gradient (DDPG) algorithm with the optimal MPC result under full information and a practice-oriented rule-based approach. I describe a structured solution path to transform a MILP into a DRL implementation. I show that the proposed DRL algorithm outperforms the rule-based approach and achieves a high level of self-sufficiency with only limited comfort violations and less cost. Analyzing different DRL formulations, I conclude that domain knowledge is essential to formalizing an efficient decision problem with stable results.
Our input data and models developed using the Julia programming language, are available open source.Der Gebäudesektor ist einer der Hauptverursacher des weltweiten Energieverbrauchs und der CO2-Emissionen. Effiziente Energiemanagementsysteme und Sektorenkopplung spielen eine Schlüsselrolle bei der erfolgreichen Umsetzung der Energiewende im Gebäudesektor. Darüber hinaus fordert die Europäische Kommission, dass sich mehr kleine Erzeuger erneuerbarer Energien aktiv in die Energiewertschöpfungskette einbringen können sollen.
In meiner ersten Studie analysiere ich die strukturellen Eigenschaften, die mit der optimalen Steuerung eines Gebäudeenergiemanagementsystems verbunden sind, sowie die Auswirkungen gängiger technologischer Konfigurationen und Zielfunktionen. Ich formuliere ein intelligentes Gebäudeenergiemanagementsystem (SHEMS) mit dem Ansatz der modellprädiktiven Steuerung (MPC) als gemischt-ganzzahliges lineares Problem (MILP). Zusätzlich analysiere ich den Einfluss verschiedener Prognosehorizonte auf die Modellgüte.
In meiner zweiten Studie modelliere ich einen illustrativen Peer-to-Peer-Markt (P2P) mit Marktpreisen, die auf den Reservationspreisen der Marktteilnehmer im aktuellen deutschen Umlagesystem basieren. Durch die Analyse des profit- und komfortmaximierenden Verhaltens der Marktteilnehmer:innen evaluiere ich das derzeitige Umlagesystem und schlagen zwei zusätzliche Marktdesigns vor.
In meiner dritten Studie analysiere ich das Potenzial von Deep Reinforcement Learning (DRL) zur Steuerung von SHEMS. Der Algorithmus ist modellfrei, kennt also das physikalische Gebäudemodell nicht und berücksichtigt nur aktuell verfügbare Informationen und keine Prognosen. Der Algorithmus lernt autonom auf Grundlage der von einer SHEMS-DRL-Umgebung erzeugten Feedbacksignale.
Ich führe alle Studien durch, indem ich ein repräsentatives Wohngebäude mit einer modulierenden Luftwärmepumpe, einer Photovoltaik-Anlage, einer Batterie und thermischen Speichersystemen für Fußbodenheizung und Warmwasserversorgung modelliere. Darüber hinaus erlaube ich die Netzeinspeisung mit einer festen Vergütung und berücksichtige den Nutzerkomfort der Bewohner.
In meiner ersten numerischen Analyse stelle ich fest, dass die Batterie der wesentliche Baustein zur Verbesserung der Autarkie ist. Um den PV-Überschuss effizient nutzen zu können, ist jedoch Netzeinspeisung erforderlich. Basierend auf der optimalen Steuerung und unter Berücksichtigung von saisonalen Effekten leite ich die dominante Reihenfolge der Nachfrageerfüllung und die Zielladezustände für die Speichersysteme her. Ich stelle fest, dass die Lösungszeit bei akzeptablen Gewinnverlusten deutlich reduziert werden kann, indem man die Autarkie statt des Gewinns maximiert oder zu einem rollierenden Plannungsansatz übergeht.
In meiner zweiten numerischen Analyse belege ich, dass ein P2P-Markt im derzeitigen Umlagesystem in Deutschland wirtschaftlich nicht tragfähig ist. Auf der Grundlage der Einspeisevergütung (FiT) und der hohen Abgaben kann kein akzeptabler Marktpreis gefunden werden. Ohne FiT oder mit reduzierten Umlagen profitieren alle Teilnehmer:innen vom P2P-Markt. Da die Produzent:innen mit Speicher auf dem P2P-Markt nicht konsumieren, sind sie von den ermäßigten Abgaben nur am Rande betroffen - am meisten profitieren die reinen Verbraucher:innen. Eine Anpassung der Regelung zugunsten der Verbraucher:innen könnte zu einer gerechteren Verteilung der Profite der Energiewende führen.
In meiner dritten numerischen Analyse vergleiche ich meine Ergebnisse, die auf dem Deep Deterministic Policy Gradient (DDPG) Algorithmus basieren, mit dem optimalen MPC-Ergebnis unter vollständiger Information und einem praxisorientierten regelbasierten Ansatz. Ich beschreibe einen strukturierten Lösungsweg, um ein MILP in eine DRL-Implementierung umzuwandeln. Ich zeige, dass der von mir vorgeschlagene DRL-Algorithmus besser abschneidet als der regelbasierte Ansatz und ein hohes Maß an Autarkie mit geringeren Kosten und nur begrenzten Komfortverletzungen erreicht. Bei der Analyse verschiedener DRL-Formulierungen komme ich zu dem Schluss, dass Expertenwissen der Schlüssel zur Formulierung eines effizienten Entscheidungsproblems mit stabilen Ergebnissen ist.
Meine Daten und Modelle, die mit der Programmiersprache Julia entwickelt wurden, sind quelloffen verfügbar
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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