<p>This presentation reports on the advances and challenges of this exciting and ever-evolving research on cities to inform and guide future studies of urban sustainability. It is based on a recent piece of research and serves two purpose, firstly it provides a snapshot and analysis of the current practices and research to achieve more sustainable cities. It presents a bibliometric analysis and contingency matrix to show the degree of correlation between journal articles and research topics. Secondly it acts as an introduction to a recent Special Issue on “Methods and applications for quantitative assessment of renewable and sustainable energy solutions at the urban scale” with the Journal of Renewable and Sustainable Energy Reviews. The research is devoted to the implementation of sustainability solutions to foster a transition towards carbon neutral cities. The focus is on research and implementation methods, plans and technologies to help the transition to a sustainable, energy efficient and regenerative society. It is hoped that this will enable social and ecological systems to maintain a healthy state and to evolve sustainably. We propose four research themes: i) renewable energy systems and public acceptance (i.e. different types of systems, qualitative assessments and social constructs); ii) building and city scale (which includes construction, operation and refurbishment); iii) Sustainability transition and multi-scale models (considering urban sustainability transition from building to districts, or cities and regions to multi-country comparisons); and iv) Climate governance and policy making (climate change mitigation and adaptation plans/policies that are reported across countries, urban services and infrastructures). To position the state of the art we present a contingency matrix with the most relevant research. We provide a heat-map matrix and demonstrate the evolution of the research network across the world. The paper does not only provide a convergence of the research articles that are presented in these four research themes, but it also analyses the research field to demonstrate the interconnectedness between energy consumption, emissions and the competition for finite resources.</p>