1,720,965 research outputs found
A comprehensive multi-node multi-vector multi-sector modelling framework to investigate integrated energy systems and assess decarbonisation needs
Full text linkThe pathway towards decarbonised energy systems involves massive changes in adopted energy vectors, installed technologies, networks roles, and interaction capabilities. To investigate the combination of these effects, this work presents the OMNI-ES modelling framework (Optimisation Model for Network-Integrated Energy Systems), which offers a comprehensive approach to analyse multi-node, multi-vector, multi-sector energy systems. It adopts a detailed temporal and spatial resolution and implements multiple conversion options between energy vectors (electricity, hydrogen, natural gas, biomethane, biofuels, e-fuels, ...). The formulation solves the energy vector balances at each time step, taking into account sources, sinks, conversion processes, and storage systems. CO2 flows are also tracked, allowing the introduction of CO2 emission constraints that account for all contributions (fossil and biogenic, direct and indirect) and mitigation measures (capture, re-use, sequestration). In the article, OMNI-ES is applied to investigate an Italian scenario for 2050, adopting a regional (NUTS-2) resolution. The model output yields the cost-optimal energy system configuration that is capable to support the demand with net-zero CO2 emissions. Results show that the need for CO2 balance closure calls in several technologies, including massive renewable power generation (up to 20 times today’s capacities), storage systems (batteries, hydrogen, pumped hydro), biogenic sources (residual biomass and biomethane), and CO2 capture (both on fossil and biogenic sources). Networks emerge as critical elements, as the need to transport energy vectors saturates the expected capacities of grid infrastructures, especially in the case of hydrogen
The role of hydropower in decarbonisation scenarios
Full text linkAn increased penetration of renewable energy sources is essential for the energy transition. A major role will be played by wind and solar, as they are widely available. Hydropower is another crucial resource, currently covering large shares of power generation (e.g., Norway, Italy, Brazil). Despite little expected growth, in a context of increasing electrification, improved integration of hydropower can play a critical role thanks to programmable operation. This work addresses the modelling of hydropower flexibility in energy system models and analyses the impact of hydropower operation on CO2 emission-constrained scenarios. To implement the study, a detailed dataset of the Italian programmable hydroelectric plants is created, using open-source information, covering location, rated power, and storage capacity. Inflow timeseries are derived from historical operational data. These new sets of data are employed in OMNI-ES (a multi-node, multi-sector, and multi-vector energy system model) to study optimal configurations and operation of the Italian energy system in decarbonisation scenarios, such as net-zero-CO2 and Fit-for-55 targets. Considering different operational strategies and multiple historical reference years (impacting the inflow), results demonstrate significant changes in hydropower behaviour and highlight its relevance as zero-carbon resource in terms of both power and energy output, influencing the installation of other technologies
Impact of Detailed Hydropower Representation in National Energy System Modelling
No full textRenewables are becoming more and more important due to the ambitious decarbonization targets. In this scenario, the improved integration of hydropower can play a crucial role thanks to its programmable operation, which is a valuable feature. In some countries it is a primary alternative to fossil resources, for example Italy, where hydro currently covers roughly half of the renewable power generation. Hydropower flexibility poses considerable modelling challenges due to the scarce availability of data. This work aims at addressing this research gap, by analysing the impact of hydropower details on energy system models. Using open-source information, a detailed dataset of Italian hydroelectric programmable plants (pumped hydro and reservoirs) is created. For each plant, storage capacity, geographical location, and nominal power are available. The multiannual historical operational data are exploited to derive a precipitation inflow timeseries for each electricity market bidding zone, which is then distributed on power plants aggregated by administrative region. This new set of data is applied to a multi-node, multi-sector, and multi-vector energy system model, which optimises the design and operation of a carbon-neutral Italian energy system, looking at a 2050 framework with assigned energy vectors demand. Results are compared to those of a fixed-hydropower operation case, thus being able to assess how the modelled flexibility impacts the optimal solution. The analysis favours an improved understanding of future energy systems, helping to shape properly integrated systems with a great amount of non-programmable sources
The role of hydropower in decarbonisation scenarios
Full text linkAn increased penetration of renewable energy sources is essential for the energy transition. A major role will be played by wind and solar, as they are widely available. Hydropower is another crucial resource, currently covering large shares of power generation (e.g., Norway, Italy, Brazil). Despite little expected growth, in a context of increasing electrification, improved integration of hydropower can play a critical role thanks to programmable operation. This work addresses the modelling of hydropower flexibility in energy system models and analyses the impact of hydropower operation on CO2 emission-constrained scenarios. To implement the study, a detailed dataset of the Italian programmable hydroelectric plants is created, using open-source information, covering location, rated power, and storage capacity. Inflow timeseries are derived from historical operational data. These new sets of data are employed in OMNI-ES (a multi-node, multi-sector, and multi-vector energy system model) to study optimal configurations and operation of the Italian energy system in decarbonisation scenarios, such as net-zero-CO2 and Fit-for-55 targets. Considering different operational strategies and multiple historical reference years (impacting the inflow), results demonstrate significant changes in hydropower behaviour and highlight its relevance as zero-carbon resource in terms of both power and energy output, influencing the installation of other technologies
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
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