Hydrogen Energy: Challenges and Prospects (RSC Energy) - Hardcover

Rand, D A J; Dell, R M

Hardcover

ISBN 10: 085404597X ISBN 13: 9780854045976

Verlag: Royal Society of Chemistry, 2008

Inhaltsangabe

A transition to renewable and low-carbon forms of energy is being widely debated as a means of securing a sustainable future for mankind. Hydrogen Energy Challenges and Prospects, a new book from the authors of Clean Energy, considers the prospects for hydrogen as a universal energy vector and fuel for the decades to come. With no emissions other than water arising from its combustion, the potential virtues of harnessing and utilizing hydrogen correlate with recent growing concern over the security of conventional fuel supply and global climate change. This book sets out to analyze the technical situation in an objective fashion, free from the constraints of political and industrial loyalties. Areas covered include pathways to hydrogen production, prospects for carbon capture and storage, options for hydrogen storage on vehicles, fuel cells, and fuel cell vehicles. Each of the many facets of hydrogen energy is discussed and the challenges to be faced are addressed. The authors acknowledge it is not possible to reach a simple, unequivocal conclusion regarding overall prospects, since the international energy scene is so complex, and predicting long-term futures is so notoriously difficult. Nevertheless, the reader will be given compelling pointers indicative of the way in which events might develop. This topical book is ideal for undergraduates, postgraduates and academics with an interest in hydrogen energy. Government agencies and energy professionals will also find this content to be a useful reference source.

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Many papers and reports have been written in recent years extolling the virtues of hydrogen energy, while a smaller number have been negative pointing out the difficulties to be faced and dismissing the concept as unrealistic. This book sets out to analyse the technical situation in an objective fashion, free from the constraints of political and industrial loyalties. Each of the many facets of Hydrogen Energy is discussed and the challenges faced are addressed. It is not possible to reach a simple unequivocal conclusion regarding overall prospects, since the international energy situation is so complex and predicting long-term futures is notoriously difficult. Nevertheless, the authors provide pointers as to the way that events might develop in the decades ahead.

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Hydrogen Energy

Challenges and Prospects

By D.A.J. Rand, R.M. Dell

The Royal Society of Chemistry

Copyright © 2008 The Royal Society of Chemistry
All rights reserved.

ISBN: 978-0-85404-597-6

Contents

Abbreviations, Symbols and Units Used in Text, xix, 
Glossary of Terms, xxv, 
Conversion Factors for Units and Useful Quantities, xxxvi, 
Chapter 1 Why Hydrogen Energy?, 1, 
Chapter 2 Hydrogen from Fossil Fuels and Biomass, 34, 
Chapter 3 Carbon Sequestration, 67, 
Chapter 4 Hydrogen from Water, 106, 
Chapter 5 Hydrogen Distribution and Storage, 146, 
Chapter 6 Fuel Cells, 179, 
Chapter 7 Hydrogen-fuelled Transportation, 230, 
Chapter 8 Hydrogen Energy: The Future?, 275, 
Subject Index, 296, 

CHAPTER 1

Why Hydrogen Energy?

From time immemorial, mankind has burnt wood in order to keep warm and to cook food. With the discovery of coal and the development of mining engineering, a new source of fuel, of higher calorific value, became available. As populations expanded and became urbanized, wood was less readily accessible and coal assumed greater importance for heating purposes. Following the introduction of rotative steam engines in the 1780s, coal was used as the prime source of energy for the production of mechanical power. Steam engines propelled ships, railway locomotives and traction engines and also provided a universal means for generating power in factories and on farms.

Late in the 19th century, the internal combustion engine was developed. Liquid petroleum was exploited – first in North America and then across the world – and was refined to provide fuels for both petrol and diesel engines. With its greater efficiency and convenience, this new technology soon replaced steam engines for most applications. Consequently, in many countries the use of coal declined (at least in percentage terms), while that of petroleum grew rapidly.

Since the mid-20th century, natural gas fields have been found in abundance. Some of the gas is associated with oil wells, but exists on its own in other places. Where oil wells are remote from centres of population, the gas was initially seen as a by-product that had no commercial value and was therefore flared. This situation changed with the development of technology for liquefying natural gas and conveying it to market by road or by sea in cryogenic tankers. Thus, once considered to be a waste product associated with oil, natural gas is now regarded as a prime fuel. With improvements in offshore drilling technology, it became possible to seek and access reservoirs in ever-deeper waters. Often these were located conveniently close to customers, e.g., in the North Sea and the Gulf of Mexico, for the gas to be delivered by pipeline. The result is that much of the developed world has now adopted gas as the preferred fuel for space heating and cooling, for use in industry and for electricity generation. Starting with wood (a form of biomass), mankind has moved to fossil fuels – first to coal, then to petroleum and latterly to natural gas – to provide the energy needed by society. Electricity also is a useful, but secondary, form of energy since it is manufactured from primary energy sources. In the mid-1950s, commercial nuclear power was added to the range of primary energy sources.

Fossil fuels are laid down over geological time and, once used, cannot be replaced on any realistic time-scale. These fuels represent the world's energy capital. By contrast, many renewable (sustainable) forms of energy, i.e., those derived from wind, solar or marine (tidal, wave, ocean) sources, must be used as they are produced; otherwise, they are wasted. Other 'renewables' may have some storage element associated with them: biomass can be stored for short periods, while hydro energy is contained in mountain lakes or reservoirs held back by dams. Geothermal energy, like fossil fuels, is retained underground until it is required. Renewables comprise the world's current account in energy. As in financial matters, where it is easier to raid the capital account than work hard to earn money for the current account, so it is easier and cheaper to dig or drill for fossil fuels than it is to extract useful energy from renewable sources. In essence, although renewable energy is widely available, the world faces major problems in harnessing this resource — many of the forms of this energy are small-scale, diffuse and, as yet, hardly cost-competitive with fossil fuels. Moreover, those that generate electricity directly have no storage component.

Most authorities attribute the rise in the mean global temperature over recent years to the combustion of fossil fuels that has grown steadily since the Industrial Revolution. The concentration of carbon dioxide in the atmosphere has risen steadily from 280 — 300ppmv in the 18th century to 360 — 380ppmv today, an increase of around 25%. Carbon dioxide is known to absorb infrared radiation re-emitted from the Earth and is a principal 'greenhouse gas'; see Section 1.2. The progressive move from coal to oil and then to natural gas represents 'decarbonization' of fuels and is desirable in that it results in less carbon dioxide release per unit of energy produced. Natural gas (methane) has four atoms of hydrogen per carbon atom and is the limit of decarbonization without going all the way to hydrogen, which is obviously a carbon-free fuel; see Figure 1.1. The idea of introducing hydrogen as the universal vector for conveying renewable forms of energy, and also as the ultimate non-polluting fuel, is encapsulated in idealized form in Figure 1.2. This proposition is commonly known as the 'Hydrogen Economy'. The upper part of the diagram is generally referred to as the transitional phase, during which hydrogen is produced from fossil fuels; the lower part relates to the long-term, post fossil-fuel, age when hydrogen will be manufactured from renewable energy sources and used as a storage medium and as a super-clean fuel.

There is, however, a problem with the concept of a sustainable Hydrogen Economy. Within our present span of vision, renewables alone do not afford a path to a carbon-free future because they are difficult to harvest on a large scale and, as noted above, breakthroughs in cost must be achieved if these sources are to supplant fossil fuels and become commonplace. Also, there is often local opposition to the construction of renewable facilities such as hydroelectric dams or wind generators, which may spoil areas of scenic beauty or interfere with natural habitats. The counter proposition of increasing the deployment of nuclear power, which is not usually regarded as renewable energy but at least is carbon-free, is unpopular in many quarters because of concerns over radioactive waste. Nevertheless, some countries already rely on nuclear power to provide an appreciable percentage of their domestic electricity requirements, e.g., France (78%), Sweden (46%), Ukraine (45%) and Korea (36%).

Hydrogen is the most abundant element in the universe. It is a major component of stars, including the Sun, whose heat and light are produced through the nuclear-fusion process that converts hydrogen into helium. Elemental hydrogen does not occur in significant amounts on Earth and energy has to be supplied in order to extract it from water or fossil fuels. Hydrogen is therefore not a primary energy source but a secondary energy vector. Energy from primary sources can be stored in hydrogen by decomposing water using chemical, thermal or electrical...

Details zur Ausgabe

• Verlag: Royal Society of Chemistry
• Erscheinungsdatum: 2008
• Sprache: Englisch
• ISBN 10: 085404597X
• ISBN 13: 9780854045976
• Einband: Gebundene Ausgabe
• Anzahl der Seiten: 340
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: gpsr@libri.de; gpsr@libri.de; ; Friedensallee 273; Hamburg; 22763; Deutschland