Energy is a mainstay of an industrial society. It is, therefore, not surprising that many important organizations have attempted to analyze the future need for energy and the availability of various energy sources. Energy consumption growth is closely linked to population growth, although changes in life styles and efficiency improvement have a substantial influence on the per capita annual consumption. The structure of population and the share between urban and rural populations also affect energy demand (Torjman and Shaaban, 1998).
As a result of the worldwide increasing consumption of energy due to an increasing population and rising living standards in less industrialized countries, the world faces the problem of depleting energy resources and the impairing impact of present energy consumption patterns on the global climate as well as on humanity and the environment (Verfondern and Nishihara, 2005).
The risk of global climate change is of great concern to policy makers and to the public. The relation between the energy generation sector and environmental pollution is being carefully considered in industrialized countries. Before executing any power generation project, extensive and comprehensive studies are performed concerning the impact of such a project on the environment. Measures for decreasing climate change and environmental pollution are considered.
Beyond fossil fuels, the mismatch between energy consumption and energy production becomes more obvious. Nuclear facilities produce energy at a constant rate, while renewable energy facilities produce energy at a variable rate. Neither type of production matches demand. Because of day-night and seasonal variations of sunlight, the typical capacity factor of solar devices is 18%. (The capacity factor is the actual energy output in a year divided by the potential energy output if the device were operated at full capacity for the entire period.) The capacity factor for wind is about 35%. For renewable energy sources, the mismatch between generation and demand is so large that it has been estimated that if as little
I. Dincer et al. (eds.), Global Warming, Green Energy and Technology,
DOI 10.1007/978-1-4419-1017-2_6, © Springer Science+Business Media, LLC 2010
as 15% of the electricity were produced by solar or wind, there would be limited economic incentive to obtain more energy from such sources, even if they are free. This is because backup power production facilities must be built to meet demand when these renewable energy sources are not available (Forsberg, 2005).
Research and development of clean, economic, stable, safe, and abundant energy should be promoted from the viewpoint of technology as a potential measure to mitigate global warming as well as for developing large and stable energy supplies. We have various alternative energy options to fossil fuels: solar, geo-thermal, hydropower, nuclear energy, etc. While available natural energy is limited due to its stability, quality, quantity, and density, it is certain that nuclear energy has the potential to contribute a significant share of energy supply and utilization. Nuclear energy has been almost exclusively utilized for electric power generation, but the direct utilization of nuclear thermal energy can be used to increase energy efficiency and thereby facilitate energy savings in the near future. Hydrogen production is one of the key technologies for direct utilization of nuclear thermal energy (Ponomarev-Stepnoi, 2004).
Hydrogen has ideal characteristics as secondary energy carrier. It can be stored, transported with lower loss compared with electricity, and used as fuel. If necessary, the chemical energy of hydrogen can be converted into electrical energy by means of fuel cells and other devices. Since it can be produced from water and, after oxidation, it returns to water, hydrogen is "clean" from the viewpoint of environmental effects. Therefore, the realization of a "hydrogen energy system" where hydrogen and electricity serve as complementary secondary energy carriers has been considered for a long time (Onuki et al., 2005).
Two candidates for large-scale production of hydrogen in the near future are nuclear-assisted thermochemical water splitting and natural gas steam reforming. They may both serve as hydrogen-producing technologies in the transition to a hydrogen-fuelled future. It is therefore interesting to investigate their relative environmental performances to gain a better understanding of the possible roads to a hydrogen society. Most of the hydrogen produced worldwide today is from fossil fuels, primarily through steam reforming of natural gas. Fossil fuels can also be subjected to several other reactions (gasification of coal, catalytic decomposition, partial oxidation, etc.) to obtain hydrogen. Unfortunately, this fossil fuel based hydrogen is not environmentally benign and does not contribute toward reducing greenhouse gas emissions. Hydrogen has to be extracted from water, using nonfossil fuels, in order to avoid the pollution problems and resource limitations of the fossil fuel-based production technologies.
The nuclear energy-driven thermochemical cycle is one of the potential water-splitting processes for producing hydrogen that has good potential for the future. The electrolysis of water is a well-known technology, but subject to lower overall efficiencies due to the inherent inefficiency of the conversion of thermal energy to electrical energy in thermal power stations. This inefficiency can be avoided through thermochemical cycles that consist of a sequence of chemical reactions yielding a net reaction of decomposition of water (Utgikar and Ward, 2006). In this chapter we describe nuclear-based hydrogen production technologies and discussed the role of the Cu-Cl cycle for thermochemical water decom position, potentially driven by waste/process heat from a nuclear power generation station, in reducing GHG emissions.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.