Natural power for the city

In a context of economic crisis and fossil energy scarcity, finding natural and renewable energy resources has become essential for large urban areas. But it is still necessary to be able to combine energy capture and restitution systems. The short-term solution lies in a global overhaul of the production-consumption cycle and the coordination of all energy supply sources and user needs into new-generation utilities.
What are the natural energies that could be exploited on a city scale? What roles can the revegetation of the city play?
Marjorie Musy, researcher in urban microclimatology at the Ambiances architecturales et urbaines laboratory (CERMA, or architectural and urban planning) and Dorothée Descamps, agricultural engineer, shed light on these questions.