What Does the Future Hold for Geothermal Energy?

Abstract

The past five years have brought considerable changes to geothermal development. Historically high oil prices since 2005 have focused attention on renewable energy, supported by a global ambition to address greenhouse gas reduction. Geothermal developments have accelerated in many parts of the world, both in countries (such as New Zealand, Indonesia and the US) that have a traditional interest in "conventional" geothermal resources, as well as countries without a historical interest in geothermal energy (such as Australia and Germany). Some new developments have followed well-worn paths using conventional hydrothermal resources in volcanic regions, while others have struck out in new directions in Enhanced Geothermal System (EGS) projects in nonvolcanic regions. Technology has allowed for developments of conventional resources with lower temperature, restricted water access, and constrained surface utilization. EGS projects have launched in a variety of different directions and places (the US currently has six active EGS developments).

In this context, the future expansion of geothermal developments depends on exploring for new fields and overcoming technical challenges in known but not-yet-exploited fields. Two issues that are currently being addressed by the world geothermal community are: (1) the "productivity gap" in the exploitation of fields that are too hot for downhole pumps, but too cool for flash production, (2) the development of reliable EGS development procedures that can ensure sustainable flow rates and assure the public that induced seismicity will not be a problem.