Indirect GHG emissions in hydropower plants: a review focused on the uncertainty factors in LCA studies

Although Life Cycle Assessment (LCA) is standardized, there is a wide range of approaches and discussions of the methodology evaluating of environmental impacts in different contexts in energy production. This review aims to present some findings, and highlight and discuss factors that influence the Life cycle Assessments (LCAs) of Hydropower Plants (HPPs) such as: indirect emissions; different stages of HPPs (construction, operation and decommissioning), the scale/productivity of HPPs; types of projects (reservoir and run-of-river), and land use. This study presents the comparison of different energy sources through the LCA and the comparison between several HPP with their different characteristics. Most of the results obtained by HPP LCAs indicate that the construction phase is the most influential phase for indirect emissions due to the use of steel and concrete. There is an important relationship between impact and production, since plants with higher productivity will have their impacts diluted during their lifetime. The comparison of the LCA results of HPPs with the LCA of other energy sources indicates that, for the category analyzed (Global Warming Potential- GWP), HPPs have a good environmental performance considering the emissions quantified. The object of this study is indirect emissions and not direct emissions, which are important, but require another approach.  This review also indicates some uncertainties related to the LCA of the HPPs and the need to conduct future studies on the environmental impacts of UHEs. We also present suggestions that should contribute to improve the use of the LCA methodology

Proteção de estações de carregamento de veículos elétricos contra descargas atmosféricas: estudo de caso no CEAMAZON / Lightning protection of electric vehicle charging station: a case study at CEAMAZON

O vertiginoso crescimento do uso de veículos elétricos e da instalação de eletropostos cria a necessidade de se pesquisar formas de proteger essas estruturas contra danos provenientes de descargas atmosféricas, principalmente em regiões do planeta onde a ocorrência de descargas atmosféricas é abundante, como na Amazônia. Tais estruturas apresentam inúmeros componentes eletrônicos sensíveis, que podem ser facilmente danificados. Neste trabalho, avalia-se se duas estações de carregamento de veículos elétricos do Centro de Excelência em Eficiência Energética da Amazônia – CEAMAZON – estão adequadamente protegidas contra descargas atmosféricas. Para isso, tomou-se como base os estudos realizados na Ásia, Europa, além da norma brasileira. Constatou-se que, apesar do prédio do CEAMAZON possuir um SPDA adequado, os eletropostos encontram-se vulneráveis, principalmente contra os efeitos indiretos causados pela ocorrência de descargas atmosféricas nas suas proximidades

Effects of Distributed Generation on the Bidirectional Operation of Cascaded Step Voltage Regulators: Case Study of a Real 34.5 kV Distribution Feeder

This work investigates the impact of feeder bidirectional active power flow on the operation of two cascaded step voltage regulators (SVRs) located at a 34.5 kV rural distribution feeder. It shows that, when active power flow reversal is possible both by network reconfiguration and by high penetration levels of distributed generation (DG), typical SVR control mode settings are unable to prevent the occurrence of runaway condition, a phenomenon characterized by loss of SVR voltage control capabilities. Such developments are the basis for a DG pre-dispatch control strategy that aims to avoid the adverse effects of the described power flow reversal scenarios, as well as to ensure reliable operation of the utility distribution network.Comment: 8 pages, 11 figures, submitted to XXV SNPTEE 201

Full-Observable Three-Phase State Estimation Algorithm Applied to Electric Distribution Grids

This paper proposes the development of a three-phase state estimation algorithm, which ensures complete observability for the electric network and a low investment cost for application in typical electric power distribution systems, which usually exhibit low levels of supervision facilities and measurement redundancy. Using the customers´ energy bills to calculate average demands, a three-phase load flow algorithm is run to generate pseudo-measurements of voltage magnitudes, active and reactive power injections, as well as current injections which are used to ensure the electrical network is full-observable, even with measurements available at only one point, the substation-feeder coupling point. The estimation process begins with a load flow solution for the customers´ average demand and uses an adjustment mechanism to track the real-time operating state to calculate the pseudo-measurements successively. Besides estimating the real-time operation state the proposed methodology also generates nontechnical losses estimation for each operation state. The effectiveness of the state estimation procedure is demonstrated by simulation results obtained for the IEEE 13-bus test network and for a real urban feeder

Computational simulation of a diesel generator consuming vegetable oil "in nature" and air enriched with hydrogen

A diesel generator was simulated operating with palm oil as fuel and hydrogen doping the inlet air. The objective was to investigate how the addition of hydrogen can accelerate the end of vegetable oil combustion, and consequently improve the electrical efficiency of the generator set up, for the same mass flow rate of fuel. The simulations were performed using AVL BOOST software and validated with experimental data. The generator was simulated operating with 75%, 80% and 100% of the nominal load using palm oil in nature, and hydrogen being injected at the intake manifold in parcels of 5% to a maximum of 20% in energy content by replacing the main fuel. The simulations showed increase in electrical power, reduction in specific fuel consumption, improving the overall efficiency of the generator set with 100% load. Good results were obtained with operation at 75% of the nominal load

Computational simulation of a diesel generator consuming vegetable oil "in nature" and air enriched with hydrogen

Simulamos un generador diesel para operar con aceite de palma e hidrógeno como combustibles. El objetivo era investigar cómo la adición de hidrógeno puede acelerar el final de la combustión de aceite vegetal, y en consecuencia mejorar la eficiencia eléctrica del generador, para la misma tasa de flujo de masa de combustible. Las simulaciones fueron realizadas utilizando el software AVL BOOST y validadas con datos experimentales. El generador fue simulado para operar con 75%, 80% y 100% de la carga utilizando aceite de palma natural, y el hidrógeno comenzó a ser inyectado en el colector de admisión en porciones de 5% a 20% que substituían el combustible principal. Las simulaciones mostraron aumento de la potencia eléctrica, reducción en el consumo específico de combustible y mejora de la eficiencia global de la operación del conjunto generador a una carga de 100%. Resultados satisfactorios de funcionamiento se obtuvieron con carga del 75%

An automatic methodology for obtaining optimum shape factors for the radial point interpolation method

In this letter, a methodology is proposed for automatically (and locally) obtaining the shape factor c for the Gaussian basis functions, for each support domain, in order to increase numerical precision and mainly to avoid matrix inversion impossibilities. The concept of calibration function is introduced, which is used for obtaining c. The methodology developed was applied for a 2-D numerical experiment, which results are compared to analytical solution. This comparison revels that the results associated to the developed methodology are very close to the analytical solution for the entire bandwidth of the excitation pulse. The proposed methodology is called in this work Local Shape Factor Calibration Method (LSFCM)

Virtual Modeling and Experimental Validation of the Line-Start Permanent Magnet Motor in the Presence of Harmonics

The world is experiencing an accelerated energy transition that is driven by the climate goals to be met and that has driven the growth of different potential sectors such as electric mobility powered by electric motors, which continue to be the largest load globally. However, new needs in relation to power density, weight, and efficiency have led manufacturers to experiment with new technologies, such as rare earth elements (REEs). The permanent magnet motor is a candidate to be the substitute for the conventional induction motor considering the new editions of the IEC 60034-30-1, for which study and evaluation continue to be focused on identifying the weaknesses and benefits of its application on a large scale in industry and electric mobility. This work presents a FEM model to assess the line-start permanent magnet motor (LSPMM), aiming to simulate the behavior of the LSPMM under supply conditions with distorted voltages (harmonic content) and evaluate its thermal and magnetic performance. The model created in the FEM software is then validated by bench tests in order to constitute an alternative analysis tool that can be used for studies in previous project phases and even to implement predictive maintenance schemes in industries