The only book available on fuel cell modeling and control with distributed power generation applications

The emerging fuel cell (FC) technology is growing rapidly in its applications from small-scale portable electronics to large-scale power generation. This book gives students, engineers, and scientists a solid understanding of the FC dynamic modeling and controller design to adapt FCs to particular applications in distributed power generation.

The book begins with a fascinating introduction to the subject, including a brief history of the U.S. electric utility formation and restructuring. Next, it provides coverage of power deregulation and distributed generation (DG), DG types, fuel cell DGs, and the hydrogen economy. Building on that foundation, it covers:

• Principle operations of fuel cells

• Dynamic modeling and simulation of PEM and solid-oxide fuel cells

• Principle operations and modeling of electrolyzers

• Power electronic interfacing circuits for fuel cell applications

• Control of grid-connected and stand-alone fuel cell power generation systems

• Hybrid fuel cell–based energy system case studies

• Present challenges and the future of fuel cells

MATLAB/SIMULINK-based models and their applications are available via a companion Web site. Modeling and Control of Fuel Cells is an excellent reference book for students and professionals in electrical, chemical, and mechanical engineering and scientists working in the FC area.

M. HASHEM NEHRIR, PhD, is a Professor of Electrical and Computer Engineering at Montana State University-Bozeman. His primary areas of interest include modeling and control of power systems, alternative energy power generation systems, and applications of intelligent controls to power systems. In addition to this book, he is the author of two textbooks and the author or coauthor of numerous technical papers. He is a member of the IEEE PES Energy Development and Power Generation Committee and currently is Vice Chair of the IEEE PES Energy Development Subcommittee.

CAISHENG WANG, PhD, is Assistant Professor at Wayne State University in Detroit, Michigan. He has worked in the areas of both large power systems and distributed generation systems, including alternative energy sources. As a part of his doctoral research, during 2002–2006, Dr. Wang was involved in fuel cell modeling and control and design of hybrid alternative energy power generation sources, including fuel cells.

Modeling and Control of Fuel Cells

Distributed Generation ApplicationsBy M. Hashem Nehrir Caisheng Wang

John Wiley & Sons

Copyright © 2009 The Institute of Electrical and Electronics Engineers, Inc.
All right reserved.
ISBN: 978-0-470-23328-3

Chapter One

INTRODUCTION

Global environmental concerns and the ever-increasing need for electrical power generation, steady progress in power deregulation, and tight constraints over the construction of new transmission lines for long distance power transmission have created increased interest in distributed generation (DG). Of particular interest are renewable DGs with free energy resources, such as wind and solar photovoltaic (PV), and alternative energy DG sources with low emission of pollutant gases, such as fuel cell (FC) and microturbine (MT) power generation devices.

In this chapter, some background about the restructured utility that lead to increased interest in DG is given first. Then, an overview of distributed generation and its different types is addressed. Distributed generation applications of fuel cells will be covered next. Finally, since all viable types of fuel cells use hydrogen ([H.sub.2]) as fuel, the last part of this chapter covers the hydrogen economy, a need for a fuel-cell-powered society.

1.1 BACKGROUND: A BRIEF HISTORY OF U.S. ELECTRIC UTILITY FORMATION AND RESTRUCTURING

Electric utilities were initially formed in the United States in late nineteenth century and established as isolated electric systems without connection to one another. In 1920s, the isolated electric systems were interconnected to help each other in load sharing and backup power. In 1934, the U.S. Congress passed the Public Utility Holding Company Act (PUHCA), where it increased the jurisdiction of the Securities Exchange Commission as well as the jurisdiction of the Federal Power Commission. This act created incentives for the isolated utilities to expand and create regional utilities, where several state utilities joined under a regional utility company. Each entity operated in its region under an investor-owned monopoly, owning generation, transmission, and distribution. However, each utility was subject to state regulation, where the utilities' rates had to be approved by the Public Utilities Commissions.

In 1977, the U.S. Department of Energy (DOE) was created to oversee the nation's energy-related activities, and under it, the Federal Energy Regulatory Commission (FERC) was formed to establish rules for generation, transport, and quality of power, among others.

The U.S. Congress passed the Public Utilities Policy Act (PURPA) in 1978. This act encouraged the construction and integration of nonutility-owned power generation technologies, including conventional and nonconventional (renewable/alternative) energy sources, to the utility grid. Under the above act, FERC sets rules for the interconnection of these power generation sources to the utility grid. Until near the end of the twentieth century, the utilities were still operating under the vertical (monopoly) structure; each utility owned generation, transmission, and distribution in a given region.

The major Energy Policy Act, enacted by the Congress in 1992, drove the U.S. power industry into complete restructuring; now, more than 15 years later, it is still ongoing. As a result of this act, "Exempt Wholesale Generator (EWG)" entities were created with the restriction that EWGs can only sell the power they generate on the wholesale market and not on the retail market. On the contrary, electric utilities are not required to purchase power from EWGs, but they are required to purchase power from qualified power generating facilities that include renewable/alternative energy power generation facilities. This energy policy act created a major shift in regulatory power from the regional level to the federal level with FERC continuing to be its rule making body. According to the policy act, the power generating entities had transmission access for the power they generated. In 1996, FERC issued the "Mega Rule," which spelled out how open access transmission of power is to be handled. It requires the transmission system owners to treat all transmission users on a nondiscriminatory basis and file tariffs for their transmission services.

Gradually, the vertical electric utility, where one company owned generation, transmission and distribution facilities, changed to a horizontal structure. In this new paradigm, generation, transmission and distribution companies became separate and independent, namely GENCO, TRANSCO, and DISCO. Generation being the only one of the three entities that is truly deregulated, numerous independent power producers (IPPs) were formed and found an opportunity to market their power. This change also created the opportunity for large and small power marketers to be formed to begin marketing the power produced by IPPs (GENCOs). Since the start of power deregulation in 1996, FERC has promoted the formation of regional transmission organizations (RTOs).

In 1999, FERC Order 2000 required the transmission system owners to put their transmission system under the control of RTOs. Today, several regions have established independent system operators (ISOs), or are in the planning stage to establish ISOs, to operate their transmission systems and provide transmission services. In 2005, the U.S. government passed the Energy Policy Act of 2005. This act authorizes the creation of an electric reliability organization (ERO), giving it the authority to enforce compliance of all market participants with the reliability standards of the National Electric Reliability Council (NERC), which was voluntary prior to 2005. In 2006, FERC certified NERC to be the U.S. ERO. Given the close interconnection of the U.S. and Canadian electric system, NERC is also seeking recognition as the ERO from the Canadian government.

Figure 1.1a shows the structure of the vertical utility of the past, where generation, transmission, and distribution systems in one region were owned by the utility in that region and sale of power within the region took place by that utility. Figure 1.1b shows the restructured horizontal utility, where different GENCOs market their power and TRANSCOs and DISCOs arrange the transport of power to customers. Figure 1.2 shows the role of ISO in the restructured utility and the deregulated power market. ISOs oversee the transport of power from generation to transmission to distribution including the marketing (buy/sell) of electric power. The structure and different entities of ISO in a region depends on the market structure in that region. At the time of writing this book, power deregulation and utility restructuring are being actively pursued worldwide.

1.2 POWER DEREGULATION AND DISTRIBUTED GENERATION

As explained in the previous section, numerous IPPs were formed as a result of power deregulation, which also spurred the consideration of DG sources. The main reason behind this consideration was, and still is, economics and the driving market forces. The fast growth in demand for electricity along with the slow growth in generation capacity in the last quarter of the twentieth century resulted in shrinking spinning reserve margins, which as a result, made power systems vulnerable and brought about the need for additional power generation. The economic constraints behind building large central power generating stations and expanding the transmission infrastructure encouraged the consideration of DGs. DGs are modular in...