The paper reports an overview of main issues related to hosting capacity and harmonic disturbances caused by EV penetration in a Smart Grid, taking into account renewable energy sources and energy storage systems as well as non-linear loads. A new mixed deterministic and probabilistic method based on algorithms and new control strategies, able to perform EVs charging controls, is presented. The methodology shows as it is possible to achieve high levels of power quality thanks to a pre-evaluation of harmonic disturbance. Studies on real networks are reported in order to carry out indices able to define a preliminary assessment of the network hosting capacity. Suggestions and guidelines about the management of EVs charging stations are proposed and discussed in order to properly integrate them in a smart grid concept.

The present paper is a review on efficiency issues related to three important sectors of the transportation systems: railways, electrical vehicles, and marine. For the three sectors, the authors, in reference of their knowledge and research area, show the results of a wide literature analysis, in order to highlight which are the measures, in terms of technological solutions and management techniques, which are recently investigated and implemented, for improving the three transportation systems, from the point of view of efficiency. In particular, for the railway transportation sector, a wide analysis is presented, detecting which are the main measures adopted for improving the efficiency, related to the power systems for supplying trains and to the train traffic control, with a focus on the storage system integration. For electric road vehicles the analysis is focused on the plug-in electrical vehicles and on the infrastructure for their recharge, with an emphasis on how these vehicles can support the grid, e.g., through Vehicle to Grid (V2G) applications. Finally, for the marine transport service the review is related to the propulsion systems and on how the different solutions can meet the objective of efficiency.

Auxiliary battery-based substations (ABSs) can enhance conventional railway feeder systems. In particular, ABSs make DC feeders located in areas far from the AC grid, able to power high-performance passenger and freight trains and store their braking energy. The paper proposes a techno-economic method to define size, position along the track, and control parameters of an ABS, with the goal to minimize the annual cost of energy (ACOE). Our approach takes into account the replacements of battery modules within the ABS expected lifetime in order to reduce costs. Numerical simulations are carried out assuming a new generation high-performance train on a real Italian 3 kV DC railway system equipped with one ABS. Although in some cases ABSs are already cheaper solutions compared to new traditional substations, the proposed sizing method allows obtaining a further reduction in the ABS cost.

The paper proposes an optimal siting and sizing methodology to design an energy storage system (ESS) for railway lines. The scope is to maximize the economic benefits. The problem of the optimal siting and sizing of an ESS is addressed and solved by a software developed by the authors using the particle swarm algorithm, whose objective function is based on the net present value (NPV). The railway line, using a standard working day timetable, has been simulated in order to estimate the power flow between the trains finding the siting and sizing of electrical substations and storage systems suitable for the railway network. Numerical simulations have been performed to test the methodology by assuming a new-generation of high-performance trains on a 3 kV direct current (d.c.) railway line. The solution found represents the best choice from an economic point of view and which allows less energy to be taken from the primary network.

Electrified guided vehicles are normally equipped with regenerative braking devices, while traction lines are supplied by non-reversible substation, thus allowing braking energy recovery only if nearby other vehicles are absorbing power. To enhance the effectiveness of regenerative braking, some energy storage can be installed along the line. Evaluation of its cost effectiveness requires time domain simulations, performed creating simulation models using general-purpose or specialized simulation languages. In this paper, two simulation tools are used. Their respective characteristics compared. The results obtained from both of them are also useful to evaluate the effectiveness of energy storage in a real-life urban case study.