SmartEnCity’s main Objective is to develop a highly adaptable and replicable systemic approach towards urban transformation into sustainable, smart and resource-efficient urban environments in Europe through the integrated planning and implementation of measures aimed at improving energy efficiency in main consuming sectors in cities, while increasing their supply of renewable energy, and demonstrate its benefits. The underlying concept of the proposal is the Smart Zero Carbon City concept, where city carbon footprint and energy demand are kept to a minimum through the use of demand control technologies that save energy and promote raised awareness; energy supply is entirely renewable and clean; and local energy resources are intelligently managed by aware citizens, as well as coordinated public and private stakeholders. This approach will be firstly defined in detail, laid out and implemented in the three Lighthouse demonstrators (Vitoria- Gasteiz in Spain, Tartu in Estonia and Sonderborg in Denmark). The three cities will develop a number of coordinated actions aimed at: • Significant demand reduction of the existing residential building stock through cost-effective low energy retrofitting actions at district scale. • Increase in RES share of energy supply, through extensive leveraging of local potentials. • Enhance the use of clean energy in urban mobility, both for citizens and goods, by means of extensive deployment of green vehicles and infrastructure. An extensive use of ICTs is planned to achieve integration and consistency in demo planning and implementation, and to enable further benefits and secure involvement of citizens. These actions will be aligned to city-specific Integrated Urban Plans (IUPs), and the process will be replicated in two Follower cities: Lecce, (Italy), and Asenovgrad (Bulgaria) to ensure adaptability and maximize the project impact. Additionally, a Smart Cities Network will be setup to support project replication at European scale.