The economics of geothermal utilization depend on many factors, each of which is specic to the type of application. Ground source heat pump installations, for example, face many market challenges that differ signicantly from those that affect direct-use applications or power generation. These differences reect differences in the scale of the project, the characteristics and state of the technology, the customer base, the competitive milieu, and the policy and regulatory environment. In this chapter, the focus will be on the large-scale considerations that affect the economic viability of geothermal power generation. Particular attention will be paid to metrics and criteria used to evaluate competitive position in the market place, relative to other available technologies. The purpose of this discussion is to provide perspective regarding geothermal power generation costs relative to other options. Although the economics of other types of geothermal applications will not be specically discussed because they have been treated directly in Chapters 11 and 12 that detail their technological and scientic dimensions, this chapter closes with a discussion of the necessary steps for completing an economically successful geothermal project of any type.