Contact Energy is to unveil its newest geothermal power station, Te Mihi, near Taupo on Thursday.
The plant will help replace the historic Wairakei plant near Taupo, which was opened in the 1950s and is being wound down as it heads to its final closure in about a decade.
Te Mihi is a 166 megawatt plant that uses underground steam to drive turbines.
Geothermal energy is a rich resource in New Zealand and is highly rated by energy planners because it is renewable and continuous.
The plant began generating electricity late last year and is being formally dedicated by the Deputy Prime Minister, Bill English, on Thursday afternoon.