1,721,009 research outputs found
Technological and legislative status point of stationary energy storages in the EU
No full textEuropean renewable generation has been supported through several policy instruments in the last decades, and this has caused a significant growth of the renewable energy sector, spurred by the ambitious climate and energy policy targets. Despite this impetuous growth, the electricity infrastructure is not yet ready to accept increasing shares of variable renewable energy sources (RES) generation, and this is causing grid balance challenges, due to the inherently variable nature of the PV and wind energy. In order to overcome this issue, allowing higher shares of renewable generation in the energy sector, energy storage (ES) systems are becoming increasingly competitive in the global energy landscape, thanks to the positive momentum in research and innovation, making European energy supply more secure, sustainable and affordable. Despite the unarguable benefits, storage technologies still see significant needs for more education among stakeholders, since they are not familiar with technology's benefits and management solutions. In order to fill this gap, this study provides an overview of storage technologies for stationary applications in the EU (plus Bosnia-Erzegovina, Norway and Switzerland), addressing the main trends in European policy legislation, also identifying advantages and barriers for their implementation. Furthermore, based on the analysis of the US Department of Energy (DOE) storage database, the main trends in ES installations within the EU markets are identified, with reference to storage technologies. The analysis carried out in this work could help stakeholders to assess the European storage market evolution in the stationary sector, identifying the main drivers and barriers for each storage technolog
Optimization of BESS Capacity Under a Peak Load Shaving Strategy
No full textBattery energy storage systems (BESSs) are becoming increasingly competitive in the global energy landscape, thanks to the strong cost reduction that has taken place in recent years and it is expected to continue in the next future. Among the many benefits BESSs can provide, time shifting can be exploited by electricity consumers to save on the electricity bill, charging the storage during the off-peak hours and discharging when the cost of electricity is high. This paper describes a simple procedure to optimize the BESS capacity under a peak load shaving strategy, in presence of a time-of-use (TOU) electricity rate, able to guarantee, at the same time, the flattest daily power diagram and the maximum benefit for the electricity consumers, reducing both the energy and the power component of the electricity bill. A case study is also presented and the modifications of the load diagram due to the BESS operation are shown
Flexibility of grid interactive water heaters: The situation in the US
No full textAmong different solutions to increase flexibility of electricity system, grid interactive water heaters (GIWHs) can make a large contribution, against a relatively low cost. They can advantageously be used within a single building, a local energy community or within an entire distribution grid, thanks to the very fast response time, low cost, highly distributed resource and widely demonstrated technology. In the near future, the flexibility potential of GIWHs will certainly increase, thanks to the advantageous flexibility programs that have been implementing in some area of the world, with the aim of coordinating several million of GIWHs with the electricity network. In this study, we assess the potential value that the flexibility of GIWHs can bring to the electrical power system, compared to the other sources of flexibility, focusing on the US market, specifically California, Oregon and Washington. The GIWH technology and the main GIWH control strategies are described, highlighting the flexibility behaviour of GIWHs. An overview of the GIWH pilot programs currently developed in the US market is provided, and current available technologies are shown, both for new and for retrofit GIWH installations. Most of the papers discussed in the literature focus on different aspects of demand response (DR), but very few of them focus specifically on GIWHs, and none of them offers a review of GIWHs in the US context. The present work thus constitutes a research gap, and could help stakeholders to assess the US GIWH market evolution, identifying the potential value of GIWH flexibility
Flexibility Services in a Mediterranean Small Island to Minimize Costs and Emissions Related to Electricity Production from Fossil Fuels
No full textIn last years, the energy efficiency in non-interconnected islands became an important topic, since the electricity production is often based on diesel generators, thus contributing to the global warming. Italian government recently emitted two decrees to promote the introduction of renewable energy technologies in 21 non-interconnected islands, both for electrical and thermal uses. In this paper, the economic and environmental feasibility of the introduction of renewable energies in the island of Pantelleria was assessed adopting an optimization approach. Furthermore, the flexibility provided from the local desalination plant and the domestic water heaters was evaluated. The final demands for electricity, air conditioning, domestic hot water and freshwater were analyzed, and the island was schematized as a multi-carrier energy hub and optimized through a mixed integer linear programming algorithm. Results prove that the renewable energies may provide a strong reduction of operating costs and greenhouse emissions of diesel generators in non-interconnected islands, although the optimal configurations differ according to the objective function of the optimization
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Realizzazione e prova di un sistema di controllo ed interfaccia per sistemi combinati accumulo-FER. Report 2 - Progettazione esecutiva, realizzazione del prototipo e prova
Get PDFIl presente Documento riferisce sui contenuti e sui risultati della seconda fase delle attività svolte nell’ambito della ricerca dal titolo: “Progettazione, realizzazione e test di un sistema di controllo ed interfaccia per sistemi combinati accumulo-FER”, oggetto di un Accordo di Collaborazione tra ENEA e DIEETCAM (Università degli Studi di Palermo) nel quadro delle attività relative al Piano Annuale di Realizzazione 2011 dell’Accordo di Programma MSE-ENEA sulla Ricerca di Sistema Elettrico. Nel corso della seconda fase delle attività, a partire dal lavoro di definizione delle specifiche tecniche di tutti i componenti, e dell’insieme delle funzionalità del dispositivo in progetto, si è proceduto alla progettazione esecutiva del dispositivo, nonché alla realizzazione di un prototipo.
E’ stata infine condotta una campagna di test e prove al fine di: applicare e validare in ambiente simulato l’algoritmo di gestione del sistema combinato per profili di variabilità della domanda tipici di alcune utenze di media taglia del settore terziario; verificare sperimentalmente (attraverso specifici test condotti in laboratorio) il regolare funzionamento dei singoli componenti di potenza del sistema, sotto diverse condizioni operative di funzionamento (in modalità stand-alone e grid-connected); verificare sperimentalmente (attraverso specifici test condotti in laboratorio) l’operatività delle funzioni di protezione e comunicazione (verso la rete) implementate. Le attività sono state condotte in sinergia con il personale tecnico di ENEA e con la collaborazione dell’azienda Layer Electronics s.r.l. di Erice (TP)
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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