The problems related to the process of industrialisation such as biodiversity depletion, climate change and a worsening of health and living conditions, especially but not only in developing countries, intensify. Therefore, there is an increasing need to search for integrated solutions to make development more sustainable. The United Nations has acknowledged the problem and approved the "2030 Agenda for Sustainable Development". On 1st January 2016, the 17 Sustainable Development Goals (SDGs) of the Agenda officially came into force. These goals cover the three dimensions of sustainable development: economic growth, social inclusion and environmental protection. The Encyclopedia of the UN Sustainable Development Goals comprehensively addresses the SDGs in an integrated way. The Encyclopedia encompasses 17 volumes, each one devoted to one of the 17 SDGs. This volume addresses SDG 7, namely "Ensure access to affordable, reliable, sustainable and modern energy for all" and contains the description of a range of terms, which allow a better understanding and foster knowledge. Energy is crucial for achieving almost all others SDGs, from its role in the eradication of poverty through advancements in health, education, water supply and industrialization, to combating climate change. This book presents a set of papers on the state-of-the-art of knowledge and practices about energy sustainable, in terms of generation and demand energy, considering aspects of innovation, management, sources of energy, performance, society behavior, and infrastructure, among others.Concretely, the defined targets are: Ensure universal access to affordable, reliable and modern energy services Increase substantially the share of renewable energy in the global energy mix Double the global rate of improvement in energy efficiency Enhance international cooperation to facilitate access to clean energy research and technology, including renewable energy, energy efficiency and advanced and cleaner fossil-fuel technology, and promote investment in energy infrastructure and clean energy technology Expand infrastructure and upgrade technology for supplying modern and sustainable energy services for all in developing countries, in particular least developed countries, small island developing states and landlocked developing countries, in accordance with their respective programmes of support Editorial Board Md. Mahmudul Alam, Justin Bishop, Luciana Londero Brandli, Elisa Conticelli, Marcos Antonio Leite Frandoloso, Haruna Musa Moda, Matti Sommarberg