Electrification of the public transport is a raising trend in Europe, and electric buses are soon expected to enter markets as one of the most interesting options for matching urban environmental targets. Electrification is driven by both economics and politics. However, although technology is not yet fully matured and ready for wide commercialisation, a large demonstration project will facilitate the market up-take of electric buses in Europe. Furthermore, as unambiguous and extensive information about overall effects of electrified bus systems and related needs for changes on infrastructure do not exist today, UITP sees its objectives and those matching perfectly, and this led UITP to build a consortium of 40 partners, who were already considering their actions along this theme, and to collectively design the 42-months demonstration project ZeEUS – Zero-Emission Urban Bus Systems.ZeEUS project focus on the today's challenge in the electrification of bus system, the extension of the fully-electric solution to a wider part of the urban network. This goes through the development of electric vehicles of large capacity, and the creation of an infrastructure capable of providing the required charging energy, operated according to non-disruptive and grid-balancing principles.The ZeEUS project will cover innovative electric bus solutions with different types of electrical power-train systems. Full-electric battery-based busses will be demonstrated in five locations (Barcelona, Bonn, Muenster, Plzen and Rome), whereas plug-in hybrid or range-extender type of power-trains will be demonstrated in three sites (London, Glasgow and Stockholm).The lifetime of project ZeEUS is long enough to collect sufficient amount of statistically valid data and make comprehensive analysis to deliver meaningful “lessons learned”, guidelines and provide feedback to the R&D activity of manufacturers and suppliers to make technology mature for wide commercialisation.