In a critical period, when all energy resources must be evaluated, geothermal energy is an attractive alternative to fossil fuels. Geothermal resources can be categorized by three main mechanisms of heat transfer: (1) hydrothermal convection systems, (2) hot igneous systems where magma generated in the mantle or deep crust moves upward, and (3) conduction-dominated regimes.
Most geothermal exploration has been directed toward the hydrothermal convection systems in areas of young volcanic or seismic activity. Temperatures above 200° are most actively sought.
Compared with other sources, geothermal generation of electricity is small. However, the growth rate—a doubling time of 10 years—is significant. Geothermal energy is especially important to certain countries, including El Salvador, Mexico, Japan, New Zealand, and in California. It is rapidly increasing in importance in the Philippines, and probably will in Chile and Nicaragua. Although the emphasis at present is on the easily exploited vapor-dominated systems, within the next 5 years the more abundant hot-water systems will become more important.
With changes in price and advancement of technology, low-temperature hot-water convection systems and geopressured pore fluids may eventually become more extensively utilized.
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Energy Resources of the Pacific Region
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.