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Geothermal Glossary and Reports

Bore - Any structure, well or hole in the ground, which is drilled or constructed. This includes bores that access underground resources (such as groundwater, geothermal water or geothermal heat) and those not accessing underground resources (such as monitoring or geotechnical bores).

Downhole Heat Exchanger - A device installed down a bore to remove heat from a geothermal field without removing geothermal fluid. Generally uses freshwater circulated through a heat exchanger at depth.

Geothermal energy - Energy derived or derivable from and produced within the earth by natural heat phenomenon; includes all geothermal water (Resource Management Act 1991).

Geothermal field/system - A discrete area where geothermal energy is known to be found and includes all areas that are hydrologically linked. It can include a body of geothermal water, material containing heat or energy surrounding the water, and all plants, animals and surface features dependant on it.

Geothermal fluid - Combined geothermal water and steam, undifferentiated proportions of either state, or a system that utilises both steam and water.

Geothermal surface feature - Includes, but is not limited to, mud pools, sinters, hot springs, hot pools, fumeroles, tomos, geysers, geothermally influenced freshwater systems, steam vents and areas of hot ground. Surface features may or may not be of natural origin, and includes extinct or intermittent features.

Geothermal water - Water heated within the earth by natural phenomenon to a temperature of 30°C or more; includes all steam, water, water vapour and every mixture of these that have been heated naturally.

Reinjection - Geothermal fluid being pumped back into the ground to the same aquifer from which it was sourced.

Water - means water in all its physical forms whether flowing or not and whether over or under the ground. It includes fresh water, coastal water, and geothermal water. It does not include water in any form while in any pipe, tank, or cistern.



Waimangu (1)

Waimangu Geothermal Field, Rotorua District

Image: © GNS Science