This chapter addresses the energy demand in urban areas. It will show how the battle for sustainable development will prevail in cities as a result of energy consumption moderation and through the adoption of cleaner fuels. This is made possible by right policies combined with new technologies. We will examine the crucial role of local authorities in stimulating innovations, in particular in choosing the right policies, land use planning and financial incentives. We will also highlight the huge potential for energy saving thanks to Internet and Smartphones (“the Internet of Things”). We will enthusiastically see that Smart Cities can deliver energy saving and therefore money saving, sustainable development and quality of life.