NZ: Company Officially Opens Geothermal Plant

Tuaropaki Power Company Officially Opens Geothermal Plant Extension at Mokai

On Saturday 25 February 2006, the Tuaropaki Power Company held their official opening ceremony for the Mokai Geothermal Power Station extension. The 39 MW extension brings the total Mokai output up to 94 MW. This power station alone will generate almost 2% of New Zealand's total electricity requirements, and will be in the nation's top 15 stations in terms of annual output.

Tuaropaki Power Company will now be the 6th largest electricity generator in New Zealand. Geothermal power stations supply a reliable base load of generation that is independent of rainfall or wind.

The station is based around what is known as binary cycle technology. While geothermal steam does pass directly through a steam turbine, geothermal heat from steam and water is passed to a second "organic" working fluid that drives other turbines. Large banks of air-cooled heat exchangers are another feature of the station. The station was designed and built by Ormat of Israel and is similar to the Rotokawa station near Taupo, or to other designs internationally. The overall result is an efficient geothermal power station.

The station has a low profile sitting on farm land surrounded by low-lying hills. The station is not directly visible from main roads out of Taupo. The heat exchanger arrangements around the station mean that there is normally no direct release of geothermal steam at the surface. A small amount of carbon dioxide comes with the geothermal fluid and is vented above the cooling towers.

The carbon dioxide emissions are about one sixth of that of a gas-fired combined cycle power station of the same MW output. Geothermal water and condensate are reinjected into the Mokai reservoir. The station is normally quiet and is not expected to disturb either the local farm workers or farming operations.

Source: Company press release