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Über dieses Buch

The technologies of hydrogen's energetic utilization have been known for a long time. But aspects of system analysis, energy economics, and ecology that would come into play in introducing it into energy systems nave received much less attention. For those reasons, this book attempts to show the development path of a hydrogen economy, based on assured technological knowledge. One special concern has been to demonstrate, on one hand, how these developments would fit into existing energy supply structures, and, on the other, how they would contribute to further development of the energy system as a whole. With that goal in mind it is necessary to contrast the obvious advantages of hydrogen with the large efforts that would be required for its introduction. This total-systems approach led to a three-part organization of the book that also aids the reader in quickly identifying those parts that are of special interest to him. Section A essentially explains why it is necessary today to think about a new synthetic energy carrier. It also describes the irreplacable and growing role of hydrogen as a chemical raw material, and it explains technologies that al­ ready exist for its energetic use or that need further development. An attempt has also been made to prove that hydrogen's safety characteristics indeed per­ mit its handling and use as an energy carrier. Hopefully, all this will show that hydrogen, together with electricity, could be the universally employable energy carrier of a future non-fossil energy supply system.



Hydrogen as an Energy Carrier — A Guide

Hydrogen as an Energy Carrier — A Guide

This book deals with energy, and specifically with the energy carrier hydrogen. It is not a book about hydrogen chemistry. The chemical-physical specifications and characteristics of hydrogen are fundamental to the discussion, but they are taken for granted and are not really its subject.
C. J. Winter

The Importance of Hydrogen and Its Utilization Prospects


1. Energy Supply Structures and the Role of Gaseous Energy Carriers

Energy is needed as heat for industrial processes, heating purposes, cooking and producing warm water within the range of below 100 to about 1500 deg.C, as power for stationary and mobile engines, as well as for lighting and communication. By far the largest proportion (70 to 80%) goes to heating supply (Figs. 1.1 and 1.2). For that, fossil fuels — coal, oil and gas — are used. In industrial countries electricity is also used widely for this purpose. For example, one half of German electricity production is utilized for heat generation. In developing countries non-commercial biomass (firewood, plant wastes, manure) is the most important source of low-temperature heat. Stationary motive power, lighting and communication are the domain of electricity. In the transport sector liquid hydrocarbons are used almost exclusively, with the exception of electrified railroads. A relatively small proportion of fossil raw energy material is needed for the manufacture of chemical products.
J. Nitsch

2. Hydrogen Energy Applications Engineering

The following examples of hydrogen’s technical application as a secondary energy carrier should serve primarily to illustrate its uses. There is no intention of giving a complete overview of the entire, still developing field. The interested reader is referred to the extensive literature on the subject. A selection of typical applications was made from the standpoint of those aspects in which hydrogen offers special advantages over existing energy technologies. Included are its storability, its excellent compatibility to different energy systems and the manifold possibilities of combination with other energy carriers as well as its low, in some cases disappearing, pollutant emissions. In the long term, the low emissions are the main argument for its future energy engineering application [2.1].
W. Peschka

3. Hydrogen as Raw Material

Hydrogen is an important raw material for synthesizing chemical compounds and in metallurgical reduction reactions. Additionally, hydrogen is used in processing crude oil into fuels and high-value chemical products. This “nonenergetic” and “indirect energetic” utilization of hydrogen has profoundly influenced the development of hydrogen technology. Experience thus gained in the production and safe usage of large amounts of hydrogen will be important in the future utilization of hydrogen as energy carrier.
W. Schnurnberger

4. Safety Aspects of Hydrogen as Energy Carrier and Energy Storage

Hydrogen is a basic feedstock of chemical technology. For decades it has been used safely on a large scale by the chemical industry where its manufacture, storage, transport and use are essentially routine.
M. Fischer, H. Eichert

Production of Hydrogen from Nonfossil Primary Energy


5. Photovoltaic Power Generation

Photovoltaic energy conversion is based on two physical mechanisms which occur during the interaction of optical-range radiation with semiconducting solids:
  • the absorption of photons in the solid state — in other words, the conversion of a part of the photons’ energy into potential electrical energy of charge carriers, and
  • the movement/separation of charge carriers by forces which result partially from the nonequilibrium condition of the solid state in reciprocity with that radiation.
G. Bauer

6. Thermal and Mechanical Energy Production

The conversion of radiation energy into heat is currently the best known and most extensively developed method of using solar energy. The key parameters in solar plant design are temperature level and proportion of usable energy, which are determined to a great extent by the absorber surface characteristics and the radiation concentration.
J. Nitsch

7. Water-Splitting Methods

In addition to conventional, chemical water splitting methods there exist electrolytic water splitting and water splitting via thermal cycles and hybrid processes. Hydrogen production via chemical water splitting is based in conventional process technology on chemical redox reactions in which water essentially reacts with carbon or carbon monoxide. Probably the oldest method is the splitting of steam with metallic iron [7.1]:
$$ {H_2}O + Fe \to FeO + {H_2}\quad; \;\Delta {H^0} = - 9.20kJ/mol, $$
followed by the reduction of iron oxide to metallic iron with carbon monoxide:
$$ FeO + CO \to Fe + C{O_2}\quad; \;\Delta {H^0} = - 31.9kJ/mol. $$
H. Wendt, G. H. Bauer

8. Selected Technical Hydrogen Production Systems

A number of methods exist for producing hydrogen from naturally occuring hydrogen-containing compounds. However, in keeping with this book’s goal of indicating ways to supply energy without using depletable fossil resources, this chapter will discuss only those systems which produce hydrogen from water with the help of regenerative or nuclear primary energy. Figure 8.1 shows a schematic summary of the possibilities of non-fossil hydrogen production.
W. Schnurnberger, W. Seeger, H. Steeb

9. Storage, Transport and Distribution of Hydrogen

Coal deposits, petroleum and natural gas reservoirs or deposits of fissionable materials represent the earth’s energy reservoirs that are millions of years old. Their exploration, exploitation and treatment essentially do not change their low-loss storability and transportability. Only the transformation of primary energy into the prevailing secondary energy forms of heat and electricity makes it clear that the storage means offered by nature for these secondary energy forms are, measured in economic terms, very limited in their capacities. Low-loss storability and transportability decline rapidly as the energy carrier is uncoupled from its original fuel characteristics.
C. Carpetis

Design of a Future Hydrogen Energy Economy


10. Hydrogen’s Potential

Estimates of future demand for non-fossil produced hydrogen and of its potential are oriented toward two, to some extent competing goals: on one hand, its direct utilization as a gaseous or liquid energy carrier and, on the other, its use in the manufacture of synthetic natural gas and synthetic liquid energy carriers from coal, tar sands and oil shale. At present the second thrust is meeting with more interest because it is viewed as economically feasible at an earlier date, requiring changes in conversion techniques but not changes in usage [10.1–10.3]. However, it is as damaging to the environment as the present fossil energy economy [10.4, 10.9].
J. Nitsch, C. Voigt

11. Hydrogen in a Future Energy Supply System

To get some idea of the technical construction and the costs of large hydrogen plants, four plants will be described in which hydrogen is produced electrolytically with the help of unlimited energy sources. The plants differ from each other in their methods of generating electricity:
  • Solar cell plants,
  • Solar tower plants with thermal storage,
  • Paraboloid mirrors with Stirling engine,
  • Wind power plants.
J. Nitsch, C. Voigt

12. Launch Concepts for Non-Fossil Hydrogen

Before the utilization of non-fossil hydrogen as energy can be considered at all, hydrogen has to prove that it can penetrate the raw materials market. In terms of energy content, the chemical hydrogen at present is twice as expensive as the raw materials natural gas and heavy oil. This is the starting point of intensive deliberations, mostly in Canada [12.1–12.3] but also in France [12.4], about the early introduction (before the year 2000) of electrolytic hydrogen into the non-energy market. Three sources are seen as capable of providing inexpensive electricity under Canadian conditions:
  • Off-peak electricity from hydropower and nuclear plants;
  • Power from nuclear plants dedicated to hydrogen production but providing power to the grid at peak load times which is then credited towards hydrogen costs;
  • Hydropower far removed from consumer centers which can be exploited cost-effectively only with a suitable energy carrier.
J. Nitsch, C. Voigt

13. The Economics of Energy and Cooperation with Energy-Producing Countries

A considerable share of any country’s economic activity is concerned with the construction of energy supply systems, and with maintaining and expanding them. In 1982, the energy business accounted for 5.6% of the Gross National Product of the Federal Republic of Germany’s [13.1]. In 1970, this segment accounted for only 4%, but the trend has been on the upswing ever since the steep energy price increases that began in the 1970’s. Domestic investments by the energy industry are growing as well in real terms. In the decade between 1960 and 1970, they averaged 18 DM billion/a (1984 prices) [13.2]; at present they are about 25 DM billion/a, or 7% of total investments [13.3]. Half of this total is required for the expansion of the electrical supply system (including nuclear energy). Roughly 80 DM billion were spent in 1983 for the import of petroleum and natural gas, about 20% of all imports and roughly four times as much as the amount spent ten years earlier (Fig. 13.1). At present, government support for the energy business (subsidies, research funding, investment support and others) amounts to about 20 DM billion/a [13.4].
J. Nitsch, H. Klaiß


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