Short Summary

Chapter 14, Sources of Energy, covers the classification, working principles, advantages, and limitations of conventional and non-conventional sources of energy. A good energy source should release a large amount of heat per unit mass, be economical, and be easily accessible. Fossil fuels such as coal and petroleum are non-renewable sources of energy and release acidic oxides of carbon, nitrogen, and sulfur, which contribute to acid rain and the greenhouse effect. Thermal power plants burn fossil fuels to produce steam, which drives turbines to generate electricity, while hydro power plants convert the potential energy of water stored in reservoirs into electrical energy, although large dams can submerge ecosystems and may contribute to the production of greenhouse gases such as methane. Biomass is another energy source that includes charcoal and biogas, a fuel containing up to about 75% methane produced through the anaerobic decomposition of organic waste. Wind energy is harnessed using turbines, with wind farms generally requiring sustained wind speeds of at least 15 km/h for effective operation. Solar energy can be harnessed using solar cookers, which use black surfaces, glass covers, and plane reflectors to trap heat, as well as solar cell panels made from special-grade silicon and connected using silver. Energy from the sea includes tidal energy, which uses the rise and fall of tides, wave energy, and Ocean Thermal Energy Conversion (OTEC), which requires a temperature difference of at least 20°C between surface water and deep water. Geothermal energy harnesses heat from underground geological hot spots. Nuclear energy releases enormous amounts of energy through nuclear fission, in which heavy nuclei such as uranium are split, or nuclear fusion, in which light nuclei combine, according to the mass–energy relation E = Δmc²; however, nuclear energy also involves significant concerns regarding radioactive waste disposal and radiation safety.