A congestion charge pay reminder sign is seen in London in this February 19, 2007 file photo. Fear of climate change and the need to find green alternatives to dirty coal, unpopular nuclear power and unreliable gas imports from Russia, are fuelling an embryonic movement in Europe to build „smart cities”. To match feature ENERGY-CITIES/ REUTERS/Alessia Pierdomenico/Files (BRITAIN) – RTXBFOI