The role of photo-catalysis in fuel production and pollutant removal is brought out. The general mechanism of photo-catalysis is outlined. Applications of photo-catalysis in pollutant removal are discussed. The photo-catalytic reduction of carbon dioxide and process features are explored. A discussion of various semiconductor catalysts and modifications to some of them is included.
The advantages of biochemical energy sources are given. The biomass components are listed. The routes for biomass to energy conversion are outlined. The biochemical routes are given diagrammatically. The biological hydrogen production process is outlined. Fermentative hydrogen production is also discussed. A discussion on biodiesel and biogas is also introduced.
The origin of nuclear fission from the point of view of binding energy per nucleon as a function of the mass number of the atom is brought out. A set of possible nuclear fission reactions is tabulated. The energy distribution in various processes in nuclear fission is outlined. A pictorial representation of nuclear fission is given. Controlled fission and fast breeder reactors are also discussed.
This chapter traces a short history of the phenomenon of nuclear fusion. The methods of carrying out fusion reactions are briefly outlined. The criteria for considering a nuclear reaction as fusion reaction are listed together with possible nuclear reactions. The possible modes of nuclear reactions on earth are discussed in relation to nuclear fusion reactions in the sun. The conditions for a fusion reaction are considered. The so-called concept of cold fusion is briefly introduced.
The limitations of the chapters presented are brought out. The materials issue on photovoltaics is pointed out. The current status of electrochemical energy systems is outlined. The limitations of hydrogen generation are discussed. The current status of energy storage and supercapacitors is also mentioned.
The fuel properties of hydrogen are compared with other typical fuels. The options for hydrogen storage are outlined. The characteristics necessary for materials for solid-state hydrogen storage are listed. The US Department of Energy goal is also pointed out. Options for solid-state hydrogen storage are explored. The maximum storage capacity of hydrogen in each of the solid-state materials so far reported are listed. The position of carbon materials among the various solid-state options is discussed. The diversity of results for storage capacity in carbon materials is highlighted. The reasons for the diverse results reported are also pointed out.
Available solar energy is sufficient for the energy needs of the earth. Solar cells are based on semiconductors, especially crystalline silicon. The essential properties of four different types of solar cell materials are compared. The advantages of solar cells over other energy conversion devices are listed. Dye-sensitized solar cells and perovskite-based solar cells are considered. Developments especially in perovskite-based solar cells are also considered.
The possible and current technology for generating hydrogen is listed. The advantages of hydrogen as a fuel are also indicated. Details of direct electrolysis are pointed out. Steam reforming as a method for hydrogen production is considered. The biochemical hydrogen production route is also dealt with. Thermochemical, photochemical, photo-electrochemical (PEC), and photo-catalytic routes for hydrogen production are considered. Developments in the PEC and the photo-catalytic decomposition of water are considered. Modifications of semiconductors and nano-state semiconductors in PEC water decomposition are also discussed.
The aim of this article is to investigate the energy consumption of the residential sector in Cyprus and identify policy areas for intervention in view of the overall European Union legislation framework and the related Energy Performance Building Directive. Initially, we provide an overview of the energy system of Cyprus and the existing energy policies and measures. Subsequently, a questionnaire-based energy survey is developed and applied in order to obtain data regarding residential energy consumption. Data collection and analysis is organized around an Index System, tailor-made for the case of Cyprus, which allowed us to improve the understanding of household energy use in order to propose policies and measures for energy efficiency and energy savings.
Energy planning refers to providing sufficient power to human societies while at the same time underlies resource, economic environmental, social and technological constraints. The complexity of the task renders multi-criteria decision analysis techniques a useful tool in the decision process. Multi-criteria decision analysis techniques offer a transparent way of elaborating on decision problems, which include many criteria and different decision-makers. This article presents the MCDA-RES multi-criteria decision-analysis software and its application in a case-study regarding a wind-hydro hybrid energy project for an island in Greece where the performance of alternatives on a set of different criteria and the preference of the decision-makers is assessed. The analysis showed that no group consensus could be directly established; still some alternatives performed better than others and a way towards a compromise solution could be revealed.
This paper presents the development of a framework for the decomposition analysis and the design of sustainable renewable energy systems. That entails the study of sustainable renewable energy technologies (RETs) projects and programs and the socio-economic decomposition of the corresponding decision-making process. Structural aspects ( institutions, markets, etc.) and actors/public involved are taken into consideration collectively along with the other fundamental dimensions, i.e., technological, resource, environmental, and economic. The interactions of the participating actors ( e. g., regional development, private economic interests, protection of environment, building-up a market, etc.) are revealed together with relevant key socio-economic attributes and indicators. The proposed approach is considered an essential prerequisite for a successful promotion of renewable energy systems.
This article develops a methodological framework to provide insights regarding the suitability of multi-criteria techniques in the context of renewable energy planning. The second section presents main characteristics of the particular decision-making process. The third section presents the main multi-criteria analysis methods, and the fourth section reveals the requirements of the techniques for renewable energy planning and the main attributes under which these methods should be evaluated. Subsequently, in the fifth section, a comparative matrix is created with the various appropriate multi-criteria techniques and their performance. Finally in the sixth section, we present our conclusions.
Physico-chemical characteristics of raw stems of giant reed (Arundo donax L.) and of the char obtained by pyrolysis at 500 degrees C and 800 degrees C under flowing N-2, as well as char yield, were determined to examine features evolution and potential applications. The chars derived at both temperatures were found potentially suitable as solid bio-fuels. Char features and yield at the lower temperature were compared to those from pyrolysis of the stems pre-treated with a phosphoric acid solution under otherwise identical conditions. The acid treatment induced an enhanced char yield and a highly developed porous structure with surface properties similar to those characterizing activated carbons. Thermogravimetric analysis also showed substantial changes in pyrolytic behavior of the treated stems. They seem to be due to the catalytic action of the acid promoting degradation at lower temperatures compared to pyrolysis of the untreated stems.
The catalytic effect of the transition metal ions Cr 3+ and Fe 3+ on the decarboxylation of Beypazari lignite was investigated in terms of the change in calorific values of the decarboxylated lignite samples obtained after the decarboxylation process and activation energies of the decarboxylation processes. The optimum temperature to run the decarboxylation experiments was determined as 150°C and 2% Cr 3+ or Fe 3+ loadings for the raw coal samples and 1% Cr 3+ or Fe 3+ metal loadings for the demineralized coal samples were found to be the optimum values to obtain the highest calorific value coal after decarboxylation reactions. Addition of Cr 3+ or Fe 3+ to raw and/or demineralized coal samples decreased the activation energies of the decarboxylation reactions by about 40% (raw coal samples) and 30% (demineralized coal samples). Activation energies calculated for experiments with Cr 3+ loaded coal samples were lower than those for Fe 3+ loaded coal samples, indicating higher catalytic activity of Cr 3+ as a catalyst.
