Development of optimal energy management and sizing strategies for large-scale electrical storage systems supporting renewable energy sources.

284 p.El desarrollo e integración de las fuentes de energía renovable (RES) conducirá a un futuro energético más sostenible. Las plantas renovables deberán mejorar su participación y operación a través de los mercados de electricidad de una manera más controlada y segura. Además, el diseño actual del mercado está cambiando para permitir una participación inclusiva en mercados de flexibilidad. En este contexto, los sistemas de almacenamiento de energía (ESS) se consideran una de las tecnologías flexibles clave que pueden apoyar la operación de las energías renovables, mediante servicios como: 1) control de la potencia generada, 2) mejora de los errores de predicción, y 3) provisión de servicios auxiliares de regulación de frecuencia. Sin embargo, el desarrollo del almacenamiento ha sido frenado también por sus altos costos. Por lo tanto, esta tesis doctoral aborda el tema del ¿Desarrollo de estrategias óptimas de gestión y dimensionamiento de los sistemas de almacenamiento eléctrico a gran escala como apoyo a fuentes de energía renovable¿, con el objetivo de desarrollar una metodología con una perspectiva global, mediante una estrategia de gestión de energía avanzada (EMS) que aborda la gestión de activos (RES + ESS) a largo plazo y por otro lado, el cálculo del dimensionamiento y operación del almacenamiento a corto plazo (en la operación en tiempo real), para asegurar un marco adecuado que permita evaluar la rentabilidad de la integración del almacenamiento en aplicaciones conectadas a la red. La estrategia de gestión de energía propuesta es validada a través de dos casos de estudio: una planta renovable individual (eólica o solar) con almacenamiento, y un porfolio de renovables y almacenamiento

Battery Energy Storage Systems in the United Kingdom: A Review of Current State-of-the-Art and Future Applications

The number of battery energy storage systems (BESSs) installed in the United Kingdom and worldwide is growing rapidly due to a variety of factors, including technological improvements, reduced costs and the ability to provide various ancillary services. The aim of this paper is to carry out a comprehensive literature review on this technology, its applications in power systems and to identify potential future developments. At first, the main BESSs projects in the UK are presented and classified. The parameters provided for each project include rated power, battery technology and ancillary services provided, if any. In the next section, the most commonly deployed ancillary services are classified and described. At the same time, the nomenclature found in the literature is explained and harmonised. The second part of the paper focuses on future developments and research gaps: ancillary services that currently are not common but that are likely to be deployed more widely in the future will be described, and more general research topics related to the development of BESSs for power system applications will be outlined

Development of Multiport Single Stage Bidirectional Converter for Photovoltaic and Energy Storage Integration

The energy market is on the verge of a paradigm shift as the emergence of renewable energy sources over traditional fossil fuel based energy supply has started to become cost competitive and viable. Unfortunately, most of the attractive renewable sources come with inherent challenges such as: intermittency and unreliability. This is problematic for today\u27s stable, day ahead market based power system. Fortunately, it is well established that energy storage devices can compensate for renewable sources shortcomings. This makes the integration of energy storage with the renewable energy sources, one of the biggest challenges of modern distributed generation solution. This work discusses, the current state of the art of power conversion systems that integrate photovoltaic and battery energy storage systems. It is established that the control of bidirectional power flow to the energy storage device can be improved by optimizing its modulation and control. Traditional multistage conversion systems offers the required power delivery options, but suffers from a rigid power management system, reduced efficiency and increased cost. To solve this problem, a novel three port converter was developed which allows bidirectional power flow between the battery and the load, and unidirectional power flow from the photovoltaic port. The individual two-port portions of the three port converter were optimized in terms of modulation scheme. This leads to optimization of the proposed converter, for all possible power flow modes. In the second stage of the project, the three port converter was improved both in terms of cost and efficiency by proposing an improved topology. The improved three port converter has reduced functionality but is a perfect fit for the targeted microinverter application. The overall control system was designed to achieve improved reference tracking for power management and output AC voltage control. The bidirectional converter and both the proposed three port converters were analyzed theoretically. Finally, experimental prototypes were built to verify their performance

Strategy of management of storage systems integrated with photovoltaic systems for mitigating the impact on LV distribution network

This article presents an integrated storage management strategy with photovoltaic systems connected to the grid, to provide voltage regulation and losses reduction in the low voltage feeder, minimising the power supplied by the network upstream of the main transformer. A new control algorithm for battery energy storage systems (BESS) is presented embedding as a battery management algorithm for charging and discharging process. The charging of the storage system is defined by the optimization of the αk coefficient to establish the value of charging threshold power, in a distributed manner, to maximise the use of photovoltaic systems. The discharging process occurs by a given σ coefficient. A standard network model from CIGRE was used for the validation of the management strategy. It was modified with real profiles of load and irradiance with a minute resolution to adapt it to the using of the quasi-static load flow in MATLAB/Simulink. As a result, by integrating 67% of PV along with 442 kWh of BESS with its management algorithm, power import from the grid decreases up to 49.3%.The authors would like to thank the University of the BasqueCountry and TECNALIA for supporting the work done at the Universityof the Basque Country under research grant by the Carolina Foundation

Economic and technical study of integration for an energy storage system with photovoltaic plant as a power curtailment solution

Questa tesi presenta una revisione e una classificazione dei sistemi di stoccaggio esistenti e della loro applicazione, inoltre fornisce una struttura di pianificazione dell'aspetto tecnico-economico dell'integrazione di sistemi di stoccaggio con la riduzione degli impianti fotovoltaici in modo che la produzione e l'utilizzo dell'energia rinnovabile possa gradualmente spostarsi ad utilizzare questa tipologia di sistemi

Development of optimal energy management and sizing strategies for large-scale electrical storage systems supporting renewable energy sources.

284 p.El desarrollo e integración de las fuentes de energía renovable (RES) conducirá a un futuro energético más sostenible. Las plantas renovables deberán mejorar su participación y operación a través de los mercados de electricidad de una manera más controlada y segura. Además, el diseño actual del mercado está cambiando para permitir una participación inclusiva en mercados de flexibilidad. En este contexto, los sistemas de almacenamiento de energía (ESS) se consideran una de las tecnologías flexibles clave que pueden apoyar la operación de las energías renovables, mediante servicios como: 1) control de la potencia generada, 2) mejora de los errores de predicción, y 3) provisión de servicios auxiliares de regulación de frecuencia. Sin embargo, el desarrollo del almacenamiento ha sido frenado también por sus altos costos. Por lo tanto, esta tesis doctoral aborda el tema del ¿Desarrollo de estrategias óptimas de gestión y dimensionamiento de los sistemas de almacenamiento eléctrico a gran escala como apoyo a fuentes de energía renovable¿, con el objetivo de desarrollar una metodología con una perspectiva global, mediante una estrategia de gestión de energía avanzada (EMS) que aborda la gestión de activos (RES + ESS) a largo plazo y por otro lado, el cálculo del dimensionamiento y operación del almacenamiento a corto plazo (en la operación en tiempo real), para asegurar un marco adecuado que permita evaluar la rentabilidad de la integración del almacenamiento en aplicaciones conectadas a la red. La estrategia de gestión de energía propuesta es validada a través de dos casos de estudio: una planta renovable individual (eólica o solar) con almacenamiento, y un porfolio de renovables y almacenamiento

Analysis of high dc/ac ratios for pv plants with bess integration on the dc side

A integração do sistema de energia fotovoltaica e de bateria (PV-BESS) absorveu muitas atenções nos últimos anos nas comunidades de energia renovável. A indústria solar demonstrou interesse significativo em combinar armazenamento com instalações solares, pois os benefícios da integração à rede aumentaram e, ao mesmo tempo, o custo do sistema de armazenamento diminuiu. Impulsionadas pelos melhores retornos, variabilidade de recursos, degradação de módulos solares e o melhor uso de inversores e sistemas de média tensão e subestação de subida, as unidades de conversão de energia, conjunto de inversores e transformadores de baixa e média tensão, geralmente são classificadas para energia CA valores inferiores aos instalados no lado CC para usinas solares em escala de utilidade. Esta dissertação demonstra que, ao aumentar a relação CC / CA da usina fotovoltaica, seria possível melhorar a controlabilidade da geração solar e a economia do projeto com a integração do tamanho BESS adequado no sistema. A análise de dados sobre a razão CC / CA para usina fotovoltaica com integração BESS no lado DC será fornecida para demonstrar a quebra de preço típica com as análises de custo-benefício baseadas em métricas de avaliação financeira, para a avaliação econômica de usinas fotovoltaicas sujeitas a forte variação quando aplicada à avaliação do BESS. Outra vantagem do sistema proposto é aumentar a quantidade de energia disponível na planta híbrida, apenas aumentando sua relação CC / CA, mantendo todo o sistema CA (ou seja, cabos, principais transformadores de energia, linhas de transmissão) essencialmente o mesmo. Isso apenas pode apresentar uma boa vantagem sobre as aplicações típicas do BESS, que essencialmente apenas arbitram a energia CA já disponível no sistema. Além disso, os benefícios econômicos que podem ser obtidos a partir de um BESS dependem da aplicação, do tamanho do sistema fotovoltaico, da sofisticação do equipamento de controle do sistema, da estrutura de taxas do cliente e dos custos operacionais. Este trabalho abrange a revisão de literatura necessária para estabelecer as bases do raciocínio para o desenvolvimento de uma metodologia para determinar o fluxo de energia entre os módulos solares e o sistema de bateria, bem como a análise do indicador financeiro que serve para medir a viabilidade de um investimento

Challenges to the Integration of Renewable Resources at High System Penetration

Successfully integrating renewable resources into the electric grid at penetration levels to meet a 33 percent Renewables Portfolio Standard for California presents diverse technical and organizational challenges. This report characterizes these challenges by coordinating problems in time and space, balancing electric power on a range of scales from microseconds to decades and from individual homes to hundreds of miles. Crucial research needs were identified related to grid operation, standards and procedures, system design and analysis, and incentives, and public engagement in each scale of analysis. Performing this coordination on more refined scales of time and space independent of any particular technology, is defined as a “smart grid.” “Smart” coordination of the grid should mitigate technical difficulties associated with intermittent and distributed generation, support grid stability and reliability, and maximize benefits to California ratepayers by using the most economic technologies, design and operating approaches

A Probabilistic Forecast-Driven Strategy for a Risk-Aware Participation in the Capacity Firming Market: extended version

This paper addresses the energy management of a grid-connected renewable generation plant coupled with a battery energy storage device in the capacity firming market, designed to promote renewable power generation facilities in small non-interconnected grids. The core contribution is to propose a probabilistic forecast-driven strategy, modeled as a min-max-min robust optimization problem with recourse. It is solved using a Benders-dual cutting plane algorithm and a column and constraints generation algorithm in a tractable manner. A dynamic risk-averse parameters selection strategy based on the quantile forecasts distribution is proposed to improve the results. A secondary contribution is to use a recently developed deep learning model known as normalizing flows to generate quantile forecasts of renewable generation for the robust optimization problem. This technique provides a general mechanism for defining expressive probability distributions, only requiring the specification of a base distribution and a series of bijective transformations. Overall, the robust approach improves the results over a deterministic approach with nominal point forecasts by finding a trade-off between conservative and risk-seeking policies. The case study uses the photovoltaic generation monitored on-site at the University of Li\`ege (ULi\`ege), Belgium.Comment: Extended version of the paper accepted for publication in IEEE Transactions on Sustainable Energ

Grid-Connected Energy Storage Systems: State-of-the-Art and Emerging Technologies

High penetration of renewable energy resources in the power system results in various new challenges for power system operators. One of the promising solutions to sustain the quality and reliability of the power system is the integration of energy storage systems (ESSs). This article investigates the current and emerging trends and technologies for grid-connected ESSs. Different technologies of ESSs categorized as mechanical, electrical, electrochemical, chemical, and thermal are briefly explained. Especially, a detailed review of battery ESSs (BESSs) is provided as they are attracting much attention owing, in part, to the ongoing electrification of transportation. Then, the services that grid-connected ESSs provide to the grid are discussed. Grid connection of the BESSs requires power electronic converters. Therefore, a survey of popular power converter topologies, including transformer-based, transformerless with distributed or common dc-link, and hybrid systems, along with some discussions for implementing advanced grid support functionalities in the BESS control, is presented. Furthermore, the requirements of new standards and grid codes for grid-connected BESSs are reviewed for several countries around the globe. Finally, emerging technologies, including flexible power control of photovoltaic systems, hydrogen, and second-life batteries from electric vehicles, are discussed in this article.This work was supported in part by the Office of Naval Research Global under Grant N62909-19-1-2081, in part by the National Research Foundation of Singapore Investigatorship under Award NRFI2017-08, and in part by the I2001E0069 Industrial Alignment Funding. (Corresponding author: Josep Pou.