An overview of the state of geothermal energy

Abstract

This paper provides an overview of the present status of geothermal energy world-wide. Although the origin of this form of energy dates back in history, its impetus (with the notable exceptions of Italy and Iceland) was the ‘energy crisis’ of the mid to late 1970s. A wide range of speculations were made during those years as to the potential contribution of geothermal energy to the world energy demand. The present lull in the energy scene allows a more realistic assessment of present and near future potential. Problem areas related to the development of the geothermal resource potential are also discussed. They address both natural, mainly liquid dominated, sources and the recovery of heat stored at depth in impervious rocks through man-made geothermal reservoirs known as the hot dry rock concept of heat mining.