New Zealand Geothermal Exploration and Exploitation Developments1
New Zealand has announced a threefold to fourfold increase in the rate of geothermal development. This involves investigation of areas with a wide range of exploration and exploitation features and problems. Wairakei continues to produce about 1,200 GWh annually—over 6% of New Zealand’s total electricity generation.
The decision has been made to commission a second major station at Broadlands. Research continues to explore the area to greater depths (2 km) in graywacke basement 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 high producing wells, with a probable future additional use for electricity.
Ngawha’s location, 200 km north of New Zealand’s main city of Auckland, is critical in an area lacking significant indigenous energy resources. For Ngawha to produce its expected 100 to 400 MW of power, adequate permeability must be found at depth in the basement graywackes.
Other areas currently being explored include Rotokaua, Taupo, Ruahine (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 increased efficiency and the use of lower grade heat. Low-grade heat is far more widespread than geothermal areas, whose continued 25-year potential is currently estimated at 2,000 MW.
Figures & Tables
The energy and mineral resources of the vast Pacific basin and its neighboring land areas play a vital role in meeting the ever-growing needs of society worldwide. Building on the foundation of a highly successful conference held in 1978, this volume contains 51 of the 135 papers presented there. Subjects included are general and specific in nature--oil, gas, and coal resources; geothermal fields, uranium; tin; evaporites, trace elements; water resources; magma energy and fuels from magma. Geological and geophysical techniques, and also the new tool of remote sending for petroleum and minerals exploration are represented. Tectonics, structure fundamentals, subsurface hazards, international treaties and the law of the deep sea are discussed. Seventeen countries and regions are represented in these papers: Thailand, Nicaragua, the United States, Japan, Peru, Antarctica, El Salvador, Australia, Mexico, Taiwan, New Zealand, China, Chile, Indonesia, Canada, and the Pacific Ocean.