The production of electricity using geothermal energy employs technology that is fundamentally indistinguishable from that at most other power generating facilities. Specically, an electrical generator is powered by a turbine that converts thermal or kinetic energy into electricity. In fossil-fueled power plants, thermal energy drives the turbine, whereas in hydropower plants, the kinetic energy derived from owing water drives the turbines. However, in two important respects geothermal power production is unique when compared to other power production methods. First, when compared to power generating technologies that supply baseload power, such as fossil-fueled power plants, biomass reactors, or nuclear reactors, there is no fuel cycle required to generate heat because the heat already exists within the earth. Second, when compared to other renewable energy technologies that do not require a fuel cycle for heat generation, such as wind, solar, tidal, or ocean wave technologies, geothermal is not intermittent and provides true baseload capability at a reliability that consistently exceeds 90%. The remainder of this chapter addresses the physics of power generation as it relates to geothermal power production and design issues that are specic to particular types of geothermal resources. For a detailed discussion of geothermal power plant design see the presentation by DiPippo (2008).