An innovative approach in steam field management has resulted in increased renewable electricity generation in the Rotokawa and Nga Awa Purua geothermal power stations in Rotokawa steamfield located north of Taupo in New Zealand.
In the new system, the geothermal fluid discharged by the wells is split into dedicated steam and brine streams. Each stream goes into one of the two geothermal power stations, both of which have been modified to be powered either by steam or brine.
This change has resulted in an additional 5MW of generation. 2MW of this comes from the Rotokawa power station, wholly owned by Mercury and with an original output of 36.5 MW. Another 3MW of additional capacity comes from the 139-MW Nga Awa Purua power station, which is co-owned by Mercury and Tauhara North No 2. Trust.
The $30 million investment on the project goes towards not only increasing the field’s output, but also enhancing the longevity of the Rotokawa Reservoir. “Thanks to the innovative approach our team is taking, we’re harnessing this technology to generate more renewable electricity, while protecting our environment at the same time. It’s a win – win,” said Steward Hamilton, General Manager Generation of Mercury.
“The geothermal reservoir is our ‘Taonga tuku iho’, and as kaitiaki of this resource the sustainability of the reservoir was the most important kaupapa,” added Mana Newton, Group CEO of Tauhara North No.2 Trust (TN2T), who coown assets on the Rotokawa steamfield north of Taupo. “These improvements enable us to provide more benefits
to our TN2T owners and descendants and contributes to our 100 year plan of a more sustainable and efficient relationship with Papatuanuku.”