Right next door to the Ngawha Hot Springs is the Ngāwhā Power Station:
geothermal fluids are passed through a heat exchanger where energy (heat) is transferred to a working fluid (pentane). The pentane then boils … which drives the turbines, turning the generator.
After the vapour has passed through the turbines, it is condensed back to a liquid and returned to the heat exchanger … The pentane is not consumed as a fuel, but is simply used as a working medium …
Having given up much of their energy, the geothermal fluids are returned to the deep geothermal reservoir