183,384 research outputs found

    Planning long-term maintenance for electric vehicle charging infrastructure using the Reliability Centered Maintenance (RCM) method

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    Electric vehicles (EVs) are mainly known for their advantages as emission free, energy efficient and noiseless transport, but electric mobility has never matured in the automotive market and it remains in the shadow of the internal combustion engine (ICE) vehicles. The EV penetration depends so much on the availability of the charging facilities. The availability and the performances of the charging infrastructure will have a major impact on the satisfaction of electric vehicle drivers and therefore on the future viability and successful of the technology. In this context, maintenance will play a key role to ensure appropriate levels of availability and reliability and also to keep the expensive infrastructure in good conditions for a long time: it will need to have a long and trouble free life, if it is to persuade the typical car user to change his behavior and choices. This paper will provide a long-term maintenance plan, in which the preventive maintenance tasks will be defined based on the Reliability Centered Maintenance (RCM) approach, starting from the definition of the electric vehicle charging infrastructure and explaining how it works and by which components it is constituted

    Power quality and electromagnetic compatibility: special report, session 2

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    The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

    Failure mode identification and end of life scenarios of offshore wind turbines: a review

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    In 2007, the EU established challenging goals for all Member States with the aim of obtaining 20% of their energy consumption from renewables, and offshore wind is expected to be among the renewable energy sources contributing highly towards achieving this target. Currently wind turbines are designed for a 25-year service life with the possibility of operational extension. Extending their efficient operation and increasing the overall electricity production will significantly increase the return on investment (ROI) and decrease the levelized cost of electricity (LCOE), considering that Capital Expenditure (CAPEX) will be distributed over a larger production output. The aim of this paper is to perform a detailed failure mode identification throughout the service life of offshore wind turbines and review the three most relevant end of life (EOL) scenarios: life extension, repowering and decommissioning. Life extension is considered the most desirable EOL scenario due to its profitability. It is believed that combining good inspection, operations and maintenance (O&M) strategies with the most up to date structural health monitoring and condition monitoring systems for detecting previously identified failure modes, will make life extension feasible. Nevertheless, for the cases where it is not feasible, other options such as repowering or decommissioning must be explored

    Evaluation of the spatial impacts of improved connectivity from urban transport investments. A GIS (Geographic Information System) application of the ICON indicator for urban areas.

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    A well-designed urban public transport policy provides significant benefits: reduces congestion and costs, and decreases the number of accidents and environment impacts. Accessibility indicators are used by planners to assess the spatial effects of their proposals and to identify those areas requiring actions to ensure minimum conditions of service. They are also used in decision making on the implementation of new infrastructure projects or improvement of the existing ones. The paper first reviews the ICON indicator, which evaluates the connectivity of a location to the transport networks as a function of the minimum time required to reach the connection nodes of each network and the utility provided in these nodes. In the interurban ICON these networks include roads, railways, ports and airports. ICON is being used in planning and in project appraisal in interurban contexts to quantify in an understandable way the relationship between transport infrastructure and services endowment and variables that are spatially defined. But it has been seldom used in the urban environment context because its particularities introduce important methodological difficulties. The paper presents the adaptation of the ICON indicator to the public transport endowment of urban areas. It includes (a) the definition of a suitable URBan Indicator of CONnectivity (URBICON) providing a quantified spatial measure of connectivity to the transport networks and (b) an analysis of the possible uses of URBICON in regional, urban and transport planning and in project appraisal, through its integration with other spatial information (population, economic activity) and GIS tools. An application to the case of the city of Barcelona is presented, considering the public transport endowment in the year 2004. The URBICON provides an easy way to detect the areas that were poorly covered by the public transport system in 2004. Some of them are already covered by new or improved infrastructures and services and others should be served by 2014. This possibly shows that the zones detected by the URBICON correspond to those where planners have somehow decided to improve public transport services. URBICON thus appears as a powerful quantitative indicator to support urban planning.

    Costs of Interchange: A Review of the Literature.

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    Interchange within mode influences the demand for that mode through the effect it has on time spent waiting, time spent transferring between vehicles and the inconvenience and risks involved, whilst interchange between modes has additional implications in terms of information provision, through ticketing and co-ordination. The valuation and behavioural impact of each of these factors will vary with an individual’s socio-economic and trip characteristics as well as with the precise features of the interchange. A reduction in the costs of interchange brought about by an improvement to any of the above factors will lead to increasingly ‘seamless journeys’ and such benefits which must be quantified. Indeed, this issue has been identified as an area of key importance in the Government’s Transport White Paper (DETR, 1998a) which states: Quick and easy interchange is essential to compete with the convenience of car use. This message was reiterated by the draft guidance for Local Transport Plans (DETR, 1998b), which called for: more through-ticketing, better connections and co-ordination of services, wider availability of information and improved waiting facilities. Rather than being perceived simply as a barrier to travel, quality interchange is now also being regarded as an opportunity to create new journey opportunities. A recent report on the subject of interchange (Colin Buchanan and Partners, 1998) claimed that : It will become more sensible and economic to base public transport networks around the concept of interchange rather than the alternative of trying to avoid it. whilst in response to the diffuse travel patterns made possible by increased car availability, CIT (1998) commented: people should readily be able to complete a myriad of journeys by changing services (and modes) if a through facility is not available. Ease of interchange should be something we take for granted. Regardless of the precise direction in which transport policy and public transport provision develop, practical constraints and the fact that the most heavily trafficked routes tend to have through services places limitations on the extent to which the need to interchange can be reduced whilst no matter how fully integrated different modes of transport are the need to transfer between them cannot be removed. In contrast, the need to change would inevitably increase with the adoption of a practice of building networks around interchange to create new journey opportunities. However, there is considerable scope to improve existing interchange situations or to design new ones which impose minimum costs. Although previous empirical research has focused on the need to interchange or not, and this remains important, it is essential that research is also directed at improvements which facilitate interchange.The aims of this study, as set out in the terms of reference, are centred around the demand side response to interchange rather than the technical supply side issues relating to improving interchange and integration which have been covered in other studies (Colin Buchanan and Partners, 1998; CIT, 1998). The objectives are: to explore the extent to which the reality and perception of interchange deters public transport use, absolutely and in relation to other deterrents to investigate how public transport users perceive interchange; how they make choices and trade-offs in travel cost and time and the influence of interchange attributes (e.g. information, through ticketing) on those choices to assess which components of interchange act as the greatest deterrent to travel to investigate the extent to which interchange penalties vary according to journey purpose, distance and time of travel (or other factors)

    Ultracapacitors for port crane applications: Sizing and techno-economic analysis

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    The use of energy storage with high power density and fast response time at container terminals (CTs) with a power demand of tens of megawatts is one of the most critical factors for peak reduction and economic benefits. Peak shaving can balance the load demand and facilitate the participation of small power units in generation based on renewable energies. Therefore, in this paper, the economic efficiency of peak demand reduction in ship to shore (STS) cranes based on the ultracapacitor (UC) energy storage sizing has been investigated. The results show the UC energy storage significantly reduce the peak demand, increasing the load factor, load leveling, and most importantly, an outstanding reduction in power and energy cost. In fact, the suggested approach is the start point to improve reliability and reduce peak demand energy consumption

    How to monitor sustainable mobility in cities? Literature review in the frame of creating a set of sustainable mobility indicators

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    The role of sustainable mobility and its impact on society and the environment is evident and recognized worldwide. Nevertheless, although there is a growing number of measures and projects that deal with sustainable mobility issues, it is not so easy to compare their results and, so far, there is no globally applicable set of tools and indicators that ensure holistic evaluation and facilitate replicability of the best practices. In this paper, based on the extensive literature review, we give a systematic overview of relevant and scientifically sound indicators that cover different aspects of sustainable mobility that are applicable in different social and economic contexts around the world. Overall, 22 sustainable mobility indicators have been selected and an overview of the applied measures described across the literature review has been presented
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