The geothermal heating system at Taupo Hospital, New Zealand

• The doublet geothermal heating system at Taupo Hospital has been running since 2010.
• The temperature of the resource has increased about 35 °C between 1966 and 1974.
• Geothermal fluid at 105 °C is produced with a down-hole pump and injected at 80 °C.

Taupo Township is located in the south western apex of the Taupo Volcanic Zone (TVZ), in the centre North Island of New Zealand, which has an abundance of high temperature geothermal resources. The Taupo Hospital sits in the south-east of the Taupo township located on the outflow zone from the Wairakei–Tauhara geothermal system. The direct-use of geothermal energy in the hospital was commissioned in August 2010 to provide space heating and domestic hot water supplies. Previously, two coal fired boilers that consumed around 340 t/year of coal were used. By converting to geothermal energy, significant savings were made in terms of operation (fuel) and maintenance costs, while no greenhouse gases are emitted to the environment. Geothermal fluid production fluctuates depending on the season. Minimum production during summer is 59 t/day and maximum production during winter is 279 t/day. The geothermal and heat exchanger system has now been running for more than four years, with no issues pertaining to scaling and corrosion. This is due to a combination of good maintenance practices and the favourable chemical composition of the geothermal fluid.