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2018 | Buch

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Off-Grid Electrical Systems in Developing Countries

verfasst von: Henry Louie

Verlag: Springer International Publishing

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

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Über dieses Buch

This book provides students and practicing engineers with a comprehensive guide to off-grid electrification: from microgrids and energy kiosks to solar home systems and solar lanterns. As the off-grid electrification industry grows, universities are starting and expanding courses and programs in humanitarian engineering and appropriate technology. However, there is no textbook that serves this growing market. This book fills that gap by providing a technical foundation of off-grid electrical systems, putting into context the technical aspects for developing countries, and discussing best practices by utilizing real-world data.

Chapters expertly integrate the technical aspects of off-grid systems with lessons learned from industry-practitioners taking a pragmatic, data-driven perspective. A variety of off-grid systems and technologies are discussed, including solar, wind, hydro, generator sets, biomass systems, battery storage and converters. Realistic examples, case studies and practical considerations from actual systems highlight the interaction of off-grid systems with the economic, environmental, social and broader development aspects of rural electrification. Whole chapters are dedicated to the operation and control of mini-grids, load and resource estimation, and design of off-grid systems.

Special topics focused on electricity access in developing countries are included, such as energy use in rural communities, technical and economic considerations of grid extension, electricity theft, metering, and best practices devoted to common problems.

Each chapter is instructor friendly and contains illustrative examples and problems that reinforce key concepts. Complex, open-ended design problems throughout the book challenge the reader to think critically and deeply. The book is appropriate for use in advanced undergraduate and graduate courses related to electrical and energy engineering, humanitarian engineering, and appropriate technology.

Provides a technical foundation of off-grid electrical systems;

Contextualizes the technical aspects for developing countries;

Captures the current and state-of-the art in this rapidly developing field.

Inhaltsverzeichnis

Frontmatter

Electricity Access

Frontmatter

Chapter 1. Energy and Development

Abstract

Human development, as measured by health, income, and education, is closely linked with access to energy. This chapter describes the state and trends of global energy and electricity consumption with a particular focus on Sub-Saharan Africa and developing countries. Different off-grid electrification approaches are described, including grid extension, mini-grids, micro-grids, energy kiosks, solar home systems, and solar lanterns.

Henry Louie

Chapter 2. Energy Poverty

Abstract

This chapter introduces the concept of energy poverty: the lack of access to modern fuels such as electricity. Design of an appropriate off-grid system requires knowing the energy uses and needs of the local community. In this chapter the typical energy consumption of houses, schools, health-care facilities, and businesses in rural off-grid communities in developing countries is discussed. Characteristics of traditional fuels such as charcoal, fuel wood, animal dung, and crop residue are provided. The role of off-grid systems such as mini-grids, micro-grids, energy kiosks, solar home systems, and solar lanterns in alleviating energy poverty is described. Methods of measuring electricity access and through the Multi-Tier Framework are presented.

Henry Louie

Chapter 3. Grid Extension and Enhancement

Abstract

In most scenarios, the fastest and most cost-effective approach to providing high-tier electricity access is by extending or enhancing the existing grid. For this reason, grid extension is the default approach to increasing electricity access. However, in situations where an off-grid community is remote, sparsely populated, and whose electricity consumption is anticipated to be low, off-grid solutions can be preferable. This chapter describes grid extension as a method for providing access to electricity. The design and operation of medium-voltage distribution lines are discussed. An economic model considering substation, medium- and low-voltage lines, transformers, and user metering and wiring is developed. The model allows the grid extension approach to be compared to off-grid approaches. The role of Rural Electrification Authorities in grid extension is detailed.

Henry Louie

Chapter 4. Off-Grid System Architectures

Abstract

The architecture of an off-grid system refers to how the various energy sources, energy storage, controllers, converters, and load are connected together. This chapter defines and describes off-grid system architectures. Examples of mini-grid architectures using conventional generators, solar power, wind power, hydropower, and hybrid combinations thereof are presented. Definitions of basic off-grid components are given.

Henry Louie

Energy Conversion Technologies

Frontmatter

Chapter 5. Off-Grid Generators, Gen Sets, and Biomass Systems

Abstract

With the exception of solar-powered systems, the electricity produced in off-grid systems is provided by a rotating generator. The operating principles, frequency, and voltage control aspects, circuit model, and efficiency of synchronous generators are described in this chapter. The mechanical power provided to the generator can come from several sources, including wind turbines, hydro turbines, and internal combustion engines. Internal combustion engines are especially common. The operating principles, efficiency, and fuel consumption of internal combustion engine-coupled generators are described in this chapter. Biomass systems are also covered as they produce biogas and syngas that can be used as fuel for internal combustion engines. In particular, anaerobic and gasification processes are detailed.

Henry Louie

Chapter 6. Off-Grid Wind and Hydro Power Systems

Abstract

This chapter continues our discussion on energy conversion technologies. The on-going cost and difficulty in maintaining a reliable supply of fossil or biomass fuel make gen sets impractical for some off-grid applications. Wind turbines, hydro turbines, and photovoltaic arrays have no fuel costs. Instead, they make use of locally available and replenishable energy sources. This chapter describes the principle of operation, modeling, analysis, and practical considerations of wind energy conversion systems and micro hydro power systems. Particular attention is given to the use of wind energy conversion systems for battery charging. The design and analysis of Pelton turbines are discussed.

Henry Louie

Chapter 7. Photovoltaic Arrays

Abstract

Photovoltaic (PV) arrays are commonly used in off-grid systems and are becoming the default choice of energy conversion technology in such applications. This is primarily driven by falling costs, and the above average sunlight in Sub-Saharan Africa and South Asia, where electrification rates are the lowest. Whereas relatively few energy-impoverished communities are in locations whose climate and terrain can support wind-, hydro-, or biomass-based generation, most have enough sunlight for PV-based generation to be practical. This chapter describes the basic operating principles of PV-arrays. Circuit models are presented, and methods for estimating the power output under different irradiance and temperature scenarios are described. Practical considerations such as the effects of shading and array design are covered.

Henry Louie

Energy Storage and Converters

Frontmatter

Chapter 8. Battery Storage for Off-Grid Systems

Abstract

Many off-grid electrical systems in developing countries use energy storage to increase their reliability and operational flexibility. The primary goals of this chapter are to provide nonspecialists with an understanding of the basic electrochemistry occurring in chemical batteries and to describe the operation and performance of batteries from an electrical viewpoint. Particular attention is given to interpreting specifications provided by battery manufacturers. A circuit model of a chemical battery is developed which is used in subsequent chapters to analyze the operation of off-grid systems. The chapter considers flooded, absorbed glass mat (AGM), gel, and various lithium–ion batteries. Safety and maintenance aspects are covered.

Henry Louie

Chapter 9. Off-Grid System Converters and Controllers

Abstract

Off-grid systems make use of a variety of converters and controllers to condition and facilitate the flow of power from source to load. This chapter begins with an introduction to the fundamentals of power electronics that are important to understanding converters and controllers: solid-state switches, pulse width modulation, and harmonics and distortion. The operating principles, applications, and practical considerations of several converters particularly relevant to off-grid systems are presented, including DC–DC converters, maximum power point trackers, solar and AC battery chargers, rectifiers, automatic voltage regulators, electronic load controllers, and inverters.

Henry Louie

Off-Grid Systems

Frontmatter

Chapter 10. Operation and Control of Off-Grid Systems

Abstract

This chapter is concerned with the operation and control of off-grid systems in rural communities in developing countries. An important consideration is the charging and discharging of the battery bank. This chapter describes the three-stage battery charging process, consisting of bulk, absorption, and float stages. Battery discharge control based on low-voltage disconnection is detailed. Methods and models for analyzing the current and power flow in off-grid systems with multiple sources, charge controllers, diversion load controllers, and loads are presented. The frequency and voltage control of synchronized generator sets is presented. The chapter concludes by describing the algorithms used in maximum power point trackers for solar photovoltaic systems.

Henry Louie

Chapter 11. Load and Resource Estimation of Off-Grid Systems

Abstract

Appropriate design of off-grid systems in developing countries requires accurate, detailed characterization of the expected load and energy resources. This chapter begins by presenting the methods commonly used to characterize the load in off-grid systems, including peak load, demand factor, load factor, and coincidence factor. Load estimation methods are the presented, including survey and data-driven methods. The data requirements for energy resource estimation are described. Methods for estimating the capacity factor of solar, wind, hydro and biomass are presented.

Henry Louie

Chapter 12. Design and Implementation of Off-Grid Systems

Abstract

This chapter considers the design and implementation of off-grid electrical systems in developing countries. The life cycle of a mini-grid is presented, from the initial decision to develop a mini-grid to site assessment and the final decommissioning or expansion. Considerations when selecting whether to use conventional or biomass-fueled generator sets, solar arrays, wind turbines, or micro hydro power are discussed. A realistic in-depth design example is provided. Design of the distribution system is discussed. The chapter concludes with economic considerations and case studies of off-grid systems in Haiti, Tanzania, and Zambia.

Henry Louie

Chapter 13. Solar Lanterns and Solar Home Systems

Abstract

Solar lanterns and solar home systems are consumer products that provide lower-tier access to electricity. Their sales have grown rapidly, exceeding 20 million units per year worldwide. Solar lanterns, also known as “pico solar,” use small solar cells or panels and batteries to provide several hours of LED-based lighting each night. Some can charge mobile phones. Solar home systems can power several lights and even small appliances. This chapter describes the basic features and design of solar lanterns and solar home systems, as well as the business models that have allowed them to rapidly proliferate in recent years.

Henry Louie

Chapter 14. Other Considerations

Abstract

We have focused so far on the technical and some economic aspects of off-grid electrification. However, there are a host of other considerations that a practitioner should be mindful of. In this chapter, we discuss several of these considerations, drawing largely upon firsthand experiences. Topics include electricity theft, use of donated equipment, counterfeit and substandard components, and human-powered electricity generation.

Henry Louie

Backmatter

Titel: Off-Grid Electrical Systems in Developing Countries
verfasst von: Henry Louie
Verlag: Springer International Publishing
Electronic ISBN: 978-3-319-91890-7
Print ISBN: 978-3-319-91889-1
DOI: https://doi.org/10.1007/978-3-319-91890-7