Resources and Development Perspectives of Geothermal Energy in Central and South America

Abstract

It is widely recognized that a large part of Central America and the whole Andean sector in South America, because of their geodynamic and volcanological conditions, have a very large geothermal potential. However, no systematic attempt has been made so far to quantify this potential, in order to provide an estimate of the reserves which are available in this region for the production of electric energy and for direct applications. The scope of the present paper is to make a first contribution in this direction. After a summary of the geological framework of the region, a categorization is made of Central and South America into type A, B and C "provinces" in accordance with a ranking of interest in descending order, depending on the expected quality of their geothermal resources. For the six type A provinces singled out in the whole region, and for the 15 preferential sectors located in them, a quantitative assessment to 3 km depth is made of the accessible resource bases. Furthermore, for each of the sectors above, the estimation is provided of the "potential reserves," subdivided into two main groups: high temperature reserves (T> 160°C), and intermediate-to-low temperature reserves (T< 160°C). For the first group, moreover, an estimation is made in terms of electric energy producible and capacity installable. The results of the estimation indicate that the minimum geothermoelectric potential of Central and South America altogether is of the order of 141-167 GWye (gigawatt- years electric), which corresponds to 5600-6700 MWe for a 25 year production period at a 100% plant capacity factor. Based on this very attractive, yet conservative, estimate, the present situation of the geothermal exploration in Central and South America is then reviewed, and the possible development targets are discussed in the light of medium- and long-term perspectives.