Abstract: New Zealand Geothermal Exploration and Exploitation Developments

D. Kear

New Zealand has announced a threefold to fourfold increase in geothermal development. This increase involves investigation of areas with a wide range of exploration and exploitation features and problems.

Wairakei continues to produce about 1,200 Gw annually, more than 6% of New Zealand's total electricity generation.

The decision has been made to commission a second major station at Broadlands (150 Mw). Research continues to explore the area to greater depths (2 km) in "graywacke" basement and to minimize pollution, corrosion, and subsidence problems. Reinjection studies continue.

Kawerau represented the first major attempt to use geothermal steam for nonelectrical purposes in a key export industry (pulp and paper). Further exploration has indicated highly productive wells, with a probable future additional use for electricity.

Ngawha is important in three respects: to produce its expected 100 to 400 Mw of power, adequate permeability must be found at depth in the basement "graywackes;" it is expected to be New Zealand's first drysteam field; and its location, 200 km north of New Zealand's main city of Auckland, is critical in an area lacking significant indigenous energy resources.

Other areas currently being explored include Rotokawa (where sulfur extraction continues), Taupo, Tikitere (near Rotorua), and Atiamuri. Prospecting techniques are being refined, and considerable planning is involved for environmentally acceptable exploitation, covering the factors of pollution, reinjection, changes in natural discharges, tourist features, and safety.

Long-term planning involves increasing efficiency and the use of lower grade heat, which is far more widespread than the geothermal areas whose 25-year potential is currently estimated at 2,000 Mw.

AAPG Search and Discovery Article #90962©1978 AAPG 2nd Circum-Pacific Energy and Minerals Resource Conference, Honolulu, Hawaii