Urban planning for a renewable energy future requires the collaboration of different disciplines both in research and practice. In the present article, the planning of a renewable energy future is approached from a designer’s perspective. A framework for analysis of the planning questions at hand is first proposed. The framework considers two levels of inquiry: the technical environmental aspect, and its wider embedding in sustainable development. Furthermore, life cycle analysis and exergy studies are discussed for their application potential in design. An altered trias energetica as proposed in earlier publications appears to remain a robust concept for low exergy, renewable energy based urban design. When considering sustainable development, environmental assessments shall be completed by an inquiry of the socio-cultural, economical, juridical, aesthetical and ethical aspects characterizing the planning or decision process. The article then presents a number of practical design principles that can help envisioning a built environment that can be sustained on the basis of renewable energy sources. In accordance with the altered trias energetica concept, elements of passive urban energy design, exergetic optimization of energy provision systems and the sourcing of renewable energy are identified, and their respective potentials assessed.