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Increasingly restrictive environmental regulations for the maritime sector have led shipping companies to look for technological alternatives to reduce emissions. This article introduces a methodology to analyse emission reductions of ships in port by incorporating batteries into the ships or using an onshore power supply system. These have not yet been considered together for comparison or with a focus on ship operation. The aim is to avoid the use of auxiliary engines in ports. First, the cost calculation method to be used is specified; then, the engine's behaviour and the established basic navigation criteria are analysed; and finally, different alternatives are considered. A methodology is afterwards defined for selecting alternatives, comparing their costs with those of using auxiliary engines in port. As an example, it is applied to a Ro-Ro route between the ports of Montoir (France) and Vigo (Spain). The results indicate that incorporating batteries into the ship produces greater savings in annual costs than onshore power supply. The cost savings from onshore power supply depend on the range of prices in each port. However, the greatest emission savings are obtained by using the onshore power supply. This methodology can be extrapolated to other routes and vessels by incorporating real operating data. [ABSTRACT FROM AUTHOR]

This paper presents a methodology that allows for the detection of the state of a sheet-metal-forming press, the parts being produced, their cadence, and the energy demand for each unit produced. For this purpose, only electrical measurements are used. The proposed analysis is conducted at the level of the press subsystems: main motor, transfer module, cushion, and auxiliary systems, and is intended to count, classify, and monitor the production of pressed parts. The power data are collected every 20 ms and show cyclic behavior, which is the basis for the presented methodology. A neural network (NN) based on heuristic rules is developed to estimate the press states. Then, the production period is determined from the power data using a least squares method to obtain normalized harmonic coefficients. These are the basis for a second NN dedicated to identifying the parts in production. The global error in estimating the parts being produced is under 1%. The resulting information could be handy in determining relevant information regarding the press behavior, such as energy per part, which is necessary in order to evaluate the energy performance of the press under different production conditions. [ABSTRACT FROM AUTHOR]

Despite most atmospheric emissions being produced by vessels when navigating at sea, they are also important when in port because of their proximity to urban areas and their harmful effects on climate change and health. First, we carried out a bibliographical review of the nine most relevant methods to estimate the emission of ships in ports. These methods have been used to estimate the emissions of the sixteen most representatives Ro–Ro (roll-on–roll-off) ships calling at the Port of Vigo. From the results obtained, a new simplified method for estimation is proposed, which is based on linear regression curves and takes into account the number of ships and the average number of hours they remain in port annually. This simplification could be a useful tool when making preliminary assessments of the emissions from ships in port, which can also be extrapolated to other ports or types of ships. [ABSTRACT FROM AUTHOR]

In this study, the behaviour of a full‐size prototype of a platform for tidal energy was analysed. The turbine of this platform is formed by two counter‐rotating rotors aligned with the tidal current, such that one rotor is always under the wake of the upstream rotor. The platform was tested under real working conditions; the tidal current was emulated by towing. The results of these tests were used to develop and parameterize a turbine model, which is presented in this paper. The turbine was modelled in terms of power, torque, and thrust coefficients. This model was used to estimate the power curve of the platform and design control strategies that, in addition to maximizing energy production, contribute to the stability of the platform. [ABSTRACT FROM AUTHOR]

Fixed-speed wind generator (FSWG) technology has an important presence in countries where wind energy started to be developed more than a decade ago. This type of technology cannot be directly adapted to the grid codes, for example those requirements related to the immunity level under voltage dips. That behavior is typically referred as low-voltage ride through (LVRT), and it usually implies certain reactive and active power injection requirements, both during a voltage dip and during the voltage recovery. In this context, a review is presented of the LVRT exigencies present in some of the countries with the most advanced grid codes (Denmark, Germany, Spain and the United Kingdom). In this paper, the capabilities of STATCOM-based devices for fulfilling the LVRT requirements in FSWGs are analyzed. For this purpose, two technologies are considered: a STATCOM with a supercapacitor, which improves its energy storage features; and a STATCOM with a supercapacitor and a DC-DC converter, to achieve higher discharge levels. [ABSTRACT FROM AUTHOR]

The Weibull probability density function (PDF) has mostly been used to fit wind speed distributions for wind energy applications. The goodness of fit of the results depends on the estimation method that was used and the wind type of the analyzed area. In this paper, a study on a particular area (Galicia) was performed to test the performance of several fitting methods. The goodness of fit was evaluated by well-known indicators that use the wind speed or the available wind power density. However, energy production must be a critical parameter in wind energy applications. Hence, a fitting method that accounts for the power density distribution is proposed. To highlight the usefulness of this method, indicators that use energy production values are also presented. [ABSTRACT FROM AUTHOR]

This paper presents a method based on dynamic programming optimization to design distribution and industrial networks with unbalanced customers. Low-voltage and medium-voltage network customers can be three-phase (i.e., industrial and commercial) and single-phase (e.g,. residential and rural areas). Moreover, American medium-voltage distribution networks have single-phase lines (rural areas) and three-phase lines (urban and primary feeders). Optimization of an unbalanced network implies optimal assignation of single-phase customers to each phase. This works considers different conductor types, tapering, power losses in lines, capacity and voltage drop constraints and deterministic loads, all employing single-phase and three-phase lines. The necessary modifications to apply it by single-win earth return systems is presented. [ABSTRACT FROM AUTHOR]