1990 - Geothermal power plant

The Ormat geothermal power plant, which was the first of its kind in New Zealand, was inaugurated on 27 February 1990, when Governor General Sir Paul Reeves opened the plant.

The first stage of developing a 7.5MW power plant, the Tarawera Ormat Installation (TOI) was a 2.6MW plant which comprised two Ormat Energy Converter (OEC) modular units. The plant was computer-controlled and utilised geothermal hot water in the temperature range of 170⁰C to 180⁰C which previously ran straight into the Tarawera River.

By channeling the water through the plant, a substantial reduction in pollution was monitored. After six weeks of testing the plant yielded 107 percent rate output relative to design point performance.