The Sustainability of Production from Geothermal Resources

Abstract

Growing worldwide population and expanding economic development are causing increased stress on the natural environment. There is a rising international awareness that we must make future development sustainable or risk catastrophic deterioration of the environment. The sustainability of production from geothermal resources is a topic that has received almost no study, leaving the question open in conjecture. As geologic phenomena, hydrothermal systems in the continental crust can be shown to persist for tens of thousands of years. However system lifetimes can be foreshortened by artificial production at the surface during geothermal energy extraction. Geothermal project feasibility studies typically deal only with developing a certain sized power plant to be run for an arbitrary period, usually 30 years. Such limited studies fail to capture a true measure of the useful energy that can be produced from a geothermal resource.

New studies are recommended to provide estimates of the sustainability of production from geothermal resources. These studies should account for (1) the energy content of the whole thermal system, not just the immediate reservoir; (2) the expectations of improving technology, leading to greater ability to mine heat and turn it more efficiently into electrical power and other products; (3) the expectation that energy prices will rise in the future; (4) the value of geothermal energy projects in preserving the environment; (5) the value of geothermal resources due to their indigenous nature; (6) the value of geothermal energy projects in providing fuel diversity and risk diversity to a utility's or a country's energy portfolio; and, (7) the potential for mining heat from hot dry rock and deep crustal resources. The recommended studies should be undertaken with full consideration of changes being brought about by such institutions as the World Bank in their quest to develop new economic analysis systems that account for measures to preserve the natural environment.