The integration of energy, water and environment systems represents important opportunities for addressing the urgent imperative of climate neutrality. The 29 original papers in the virtual special issue of the 14th Conference on Sustainable Development of Energy, Water and Environment Systems exemplify multiple advances in integrated approaches. This editorial provides a review of recent scientific contributions in energy system integration, urban synergies in the energy transition, integration of energy and water systems as well as valorization of waste heat. Advances that relate to sustainable combustion, biomass, and managing emissions provide further perspectives. All seven themes contain new research directions in such areas as solar energy technologies, thermal energy storage, power-to-X technologies, district heating and cooling networks, wastewater treatment plants, water desalination, and salinity gradient technologies. Advanced optimization approaches, big data analytics for cogeneration, thermal management applications, pollution minimization, lignocellulosic biomass, catalysts for alternative fuels as well as carbon capture, storage and utilization are described among other scientific contributions. Across the world, the focus on integration is gaining prominence, especially with the European Union Strategy on Energy System Integration that recognizes the role of a coordinated approach for planning and operating the energy system as a whole. The research advances that are contained in this editorial will support the realization of a coherent approach on the path towards sustaining the life-support systems of the planet and thereby support sustainable development.