Sustainable energy is the provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs. A broader interpretation may allow inclusion of fossil fuels and nuclear fission as transitional sources while technology develops, as long as new sources are developed for future generations to use. A narrower interpretation includes only energy sources which are not expected to be depleted in a time frame relevant to the human race. Sustainable energy sources are most often regarded as including all renewable sources, such as biofuels, solar power, wind power, wave power, geothermal power and tidal power. It usually also includes technologies that improve energy efficiency. This new and important handbook gathers the latest research from around the globe in the study of sustainable energy and highlights such topics as: monitoring sustainable energy development; methane; energy and territory; biodiesel production; electrochemical hydrogen storage; environmental policies in an electricity sector and others).