Wellington's first public electricity supply was established in 1904, alongside the introduction of electric trams, and was originally supplied at 105 volts 80 hertz. The conversion to the now-standard 230/400 volts 50 hertz began in 1925, the same year the city was connected to the Mangahao hydroelectric scheme. Between 1924 and 1968, the city's supply was supplemented by a coal-fired power station at Evans Bay.