The world first project in the Granite City was aimed at being the future of clean public transportation.
The local authority said it was a major step towards "greener, cleaner public transport".
Hull City Council says the new buses will help cut emissions and reduce noise.
The fleet consists of 18 double decker and 12 single decker buses.
Bradford Council boss Susan Hinchcliffe says "cleaner, better buses" are vital for the future.
Ian McDonald retires after driving for First Bus and its predecessors since 1974.
Devon County Council says it has been awarded £7.53 million funding for new zero emission buses.
The 186 buses, which each cost about £500,000, will replace diesel vehicles and cut harmful emissions.
Stagecoach says there will be a phased transition to a fully electric fleet in Torbay.
