RESPONSE aims to establish a strategic vision for Smart Cities Energy Transition: Climate-neutral cities by 2050. The idea is to turn energy sustainability into a doable vision by solving the energy trilemma (security, equity/affordability, environmental sustainability) at building, block and district levels in smart cities. RESPONSE supports the lighthouse cities of Dijon (FR) and Turku (FI) and their Fellow cities Brussels (BE), Zaragoza (ES), Botosani (RO), Ptolemaida (GR), Gabrovo (BU) and Severodonetsk (UA).