Charging Electric Vehicles Using Regenerated Energy from Urban Railways
Nowadays transport system is one of the most important producers of air pollution in cities. Urban railways and electric vehicle will play a fundamental role to accomplish the sustainability of cities. Urban railways are right now an efficient mode of transport. However it is necessary to continue improving its energy efficiency in view of the demand growth. On the other hand, electric vehicles need a charging infrastructure to support their market penetration. In this context, the use of the railway electrical infrastructure to charge electric vehicles could bring several benefits. First of all, there is a cost reduction effect because of the use of an existing installation. Besides, part of the regenerated energy that cannot be accepted by other trains can be used to charge electric vehicles, improving the efficiency of the global system. In this paper, a new system for the global energy management between the railway infrastructure and the electric vehicles is proposed. Besides, the global energy savings that can be obtained using railway electrical infrastructure to charge electric vehicles has been assessed.
Energy Efficiency and Integration of Urban Electrical Transport Systems: EVs and Metro-Trains of Two Real European Lines
Transport is a main source of pollutants in cities, where air quality is a major concern. New transport technologies, such as electric vehicles, and public transport modalities, such as urban railways, have arisen as solutions to this important problem. One of the main difficulties for the adoption of electric vehicles by consumers is the scarcity of a suitable charging infrastructure. The use of the railway power supplies to charge electric vehicle batteries could facilitate the deployment of charging infrastructure in cities. It would reduce the cost because of the use of an existing installation. Furthermore, electric vehicles can use braking energy from trains that was previously wasted in rheostats. This paper presents the results of a collaboration between research teams from University of Rome Sapienza and Comillas Pontifical University. In this work, two real European cases are studied: an Italian metro line and a Spanish metro line. The energy performance of these metro lines and their capacity to charge electric vehicles have been studied by means of detailed simulation tools. Their results have shown that the use of regenerated energy is 98% for short interval of trains in both cases. However, the use of regenerated energy decreases as the train intervals grow. In a daily operation, an important amount of regenerated energy is wasted in the Italian and Spanish case. Using this energy, a significant number of electric vehicles could be charged every day.
Career Choice Inclination of the College Graduates——under the Analytic Framework on the Basis of LMS Theory
Employment difficulty of college graduates has become a social problem in China today.The research group has found that college graduates have a strong inclination in career choice considering units and regions.In terms of China's manpower market and the segmented labor market theory,it is found that their inclination is caused by the great income gap of different regions,the high cost of job transfer,and the sharp differences in social welfare.It is thus obvious that solution to the problem lies with the gradual breakdown of the institutional segment of labor market.