ABSTRACT
This chapter discusses the important aspects of the slope and vertical intercept of the standard incremental energy cost curve which could be numerically calculated from the geothermal system parameters, namely, the specific heat at constant pressure and the rate of flow of hot water or steam, the sink temperature, and the plant constant. Resources of geothermal energy have been characterized into three categories, namely, hydrothermal, geopressured, and petrothermal modes. In geopressured systems hot water occupies a deep reservoir under intense pressure from multilayers of rocks, shale, and sands. This geopressured water sometimes is saturated with natural gas resulting from the decomposition of organic materials. In petrothermal systems, magna lying close to the Earth's surface heats overlying rocks to a very high temperature. Infection of water or any other fluid in petrothermal layers and then pumping it out will release a huge amount of thermal energy by driving a steam or hot water turbine.
