Energy and Sustainability 2023 is the 10th International Conference in a very successful series which started in 2007, in the New Forest, UK, home of the Wessex Institute; it was followed by meetings in Bologna (2009), Alicante (2011), Bucharest (2013), Kuala Lumpur (2014), Medellin in Colombia (2015), Seville (2017) and Coimbra (2019). The 9th 2021 meeting was organised as an online event because of the COVID pandemic. The world’s economy is fuelled by energy. Depletion of resources and severe environmental effects resulting from the continuous use of fossil fuels has motivated an increasing amount of interest in renewable energy resources and the search for energy policies leading to a sustainable future. The changes required to progress from an economy mainly relying on hydrocarbons to one taking advantage of sustainable renewable energy resources require considerable scientific research, as well as the development of new technology and design of energy systems. Energy policies and management are of primary importance to achieve sustainability and need to be compatible with recent advances in energy production and distribution. In many cases, the challenges lie as much in the conversion from renewable (wind, solar, etc.) to useful energy forms (electricity, heat, fuel) at an acceptable cost that includes the possible damage to the environment as in the integration of these renewable forms of energy into the existing infrastructure. The diverse topics covered by the conference often require the collaboration between different disciplines in order to arrive at optimum solutions; they include studies of energy networks, new energy resources, materials, storage solutions, waste to energy processes, smart grids and many others. Particular emphasis in ESUS 23 will be given to sustainability performance of buildings which is highlighted in a recent EU initiative called Level(s). A special session is planned that would provide a forum for research on the evaluation of sustainable buildings, as well as the policies aimed at a building stock and its resilient built environment within the framework of the circular economy in Europe.