1,721,063 research outputs found
Decarbonization potential of on-road fuels and powertrains in the European Union and the United States: a well-to-wheels assessment
Full text linkTransportation is fundamental for any modern economy, but its growing energy demand and the related climate impact call for urgent action. Life-cycle analysis (LCA) is a suitable approach to assessing the greenhouse gas (GHG) performance and decarbonization potential of transportation fuels and vehicle powertrains. Here, we assessed well-to-wheels (WTW) GHG emission reductions for a wide set of light-duty vehicle fuel and powertrain technologies used in the European Union (EU) and the United States (U.S.) for their decarbonization potential. We focused on the similarities and differences of the results and the underlying methodologies and data of the two analyses. We evaluated the decarbonization potential of new fuel–vehicle systems in Europe and the United States in comparison to the baseline petroleum gasoline and diesel vehicles in each market. For the transportation fuels examined in both regions, waste-to-fuel technologies and drop-in renewable diesel fuels (biofuels) produced from residues offer the biggest opportunities for reducing per-energy-unit GHG emissions, but may be limited in scale-up potentials given feedstock availabilities, qualities, and logistics challenges. The potential benefits of electricity and hydrogen as fuels span a wide range, determined by the primary energy source and the potential deployment of carbon capture and sequestration technologies. From a tank-to-wheels perspective, electric powertrains, with higher energy efficiency than internal combustion engines, provide incontrovertible evidence of GHG savings. For vehicle–fuel combined systems, the per km WTW results from GREET are generally higher than the JEC estimates, owing to greater vehicle fuel consumption attributable to larger vehicle sizes and more aggressive driving cycles in the U.S. This paper highlights key drivers of WTW fuel–vehicle system GHG emissions as well as opportunities and limitations to decarbonize light-duty transportation in Europe and the United States with promising alternative fuel production and vehicle powertrain technologies. Results show that major solutions in both regions are aligned, despite certain differences in the methodologies and results of the WTW analyses. As well as informing optimal selection of fuel and powertrain technologies for future vehicles, these findings are also useful in informing how existing vehicles can best be decarbonized through the use of renewable fuels and advanced powertrain technologies
Can Lower Carbon Aviation Fuels (LCAF) Really Complement Sustainable Aviation Fuel (SAF) towards EU Aviation Decarbonization?
Full text linkThe present work provides an analysis of the potential impact of fossil-based Low Carbon Aviation Fuels (LCAF) for the European aviation sector, with a time horizon to 2050. LCAF are a crude-derived alternative to kerosene, offering some Green House Gas (GHG) savings, and have been defined by ICAO as eligible fuels for mitigating the environmental impact of aviation. A methodological framework to evaluate the EU technical potential for LCAF production is developed, based on data on crude utilization for jet fuel production in EU refineries, relevant carbon intensity reduction technologies, market prices, and aviation fuel volumes. Two different baselines for fossil-derived kerosene carbon intensity (CI) are considered: a global figure of 89 gCO2e/MJ and an EU-27-specific one of 93.1 gCO2eq/MJ. Three scenarios considering increasing levels of CI reduction are then defined, taking into account the current and potential commercial availability of some of the most relevant carbon intensity reduction technologies. The analysis demonstrates that, even if LCAF could offer GHG saving opportunities, their possible impact, especially when compared to the ambition level set in the most recent European legislative proposals, is very limited in most of the analysed scenarios, with the exception of the most ambitious ones. At 2030, a non-zero technical potential is projected only in the higher CI reduction scenario, ranging between 1.8% and 14.2% of LCAF market share in the EU-27 (equal to 0.6 to 4.75 Mtoe), depending on the considered Baseline for CI. At 2050, almost all considered scenarios project a larger technical potential, ranging between 6.9% and 22.2% for the global Baseline (2.21 to 7.13 Mtoe), and between 1.8% and 16.2% for the EU-27 Baseline (0.58 to 5.2 Mtoe). LCAF additional costs to current production costs are also discussed, given their relevance in large-scale deployment of these technologies, and are projected to range between 39 and 46.8 USD/toe
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
Heat and Power from Biomass: Technology Market Report
No full textThis Heat and Power from Biomass Technology Market Report 2018 presents an assessment of the state of the art, development trends, targets and needs, technological barriers, as well as techno-economic projections until 2050. Particular attention is paid to how EC funded projects contributed to technology advancements. It includes an overview of Member States' activities based on information from the relevant SET Plan Temporary Working Groups as well as the objectives and main outcomes of the most relevant international programmes.JRC.C.2 - Energy Efficiency and Renewable
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
The challenge of forecasting the role of biofuel in EU transport decarbonisation at 2050: A meta-analysis review of published scenarios
No full textThe European New Green Deal and the REDII set ambitious targets, aiming to achieve a climate-neutral Europe by 2050. The transport sector is the most critical area to decarbonize, given the rigidity of both infrastructure and end-use technologies, as well as the challenge of reaching cost-effective production of sustainable advanced renewable fuels. Several researchers, stakeholders and groups of interest, such as international and governmental organisations, NGOs, business analysists, scientists and other actors elaborated scenarios on biofuels market penetration by 2050. These studies are largely used by policy makers, even if not necessarily were subject to a rigid peer review and verification process. This work presents an extensive literature review of the main published investigations, to assess and quantify the authors' different visions. These forecasts intend to evaluate the possible future development of the sector based on current and foreseeable policies, as well as industry and investors' business plans; at the same time, these estimates should also provide policy makers with a sound base for policy development towards achieving climate goals. Through preliminary screening, based on a methodology of a set of ex-ante conditions, this work identified the most relevant publications and structured the analysis of the collected data. A total of 18 publications were selected from the literature review, resulting in 56 scenarios to be examined. This work allowed to achieve a comprehensive summary and quantification of the selected scenarios, all of which focus on biofuel contribution to transport decarbonisation in the period 2030-2050. Given the occurrence of several factors, as the ongoing and future technological development, the adoption of more efficient mobility models, the hybridization and electrification of transports, the Total Fuel Consumption for the transport sector is expected to reduce in Europe: averaged projections from the analyzed scenarios account for 312.8 Mtoe in 2030 and 274.2 Mtoe in 2050. Biofuels are expected to significantly contribute to achieve the EU targets, with a progressive shift towards advanced feedstock: on average, their total contribution is expected to account for 24.5 Mtoe in 2030, and for 48.3 Mtoe in 2050, while advanced biofuels are projected for an average contribution of 8.7 Mtoe in 2030 and 36.5 Mtoe in 2050.This work analysed pre-pandemic published scenarios: the effects that the COVID-19 pandemic is having on the global as well as EU economies are uncertain, but there is a serious risk of hampering and postponing investment decisions in the whole energy area, making the achievement of RED and EU Green Deal targets even more challenging in this historical moment
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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