Chapter 3 - Geothermal energy sources

Abstract

Geothermal energy sources are known as abundant energy resources and are primarily utilized for electricity production and heating applications in a manner that is clean (effectively no harmful gaseous emissions, including CO, CO2, NOx, SOx, etc.) and safe and reliable (renewable and sustainable). These sources are expected to play a significant role in meeting the world’s energy needs. Geothermal water, as it comes from underground, contains gas impurities, such as hydrogen sulfite and radon gas, whose release to the ambient is generally not permitted. The reinjection of utilized geothermal water back into the injection well may, however, solve any harmful emission problems. Thermal energy is created over millions of years by the natural decay of radiogenic materials, including uranium, thorium, and potassium. Geothermal power generation plants have significant advantages. They are environmentally benign, renewable power resources, and they can be utilized for providing base-load electrical power and thermal energy for industrial applications. The geothermal power resources that have been used or that are under investigation for improvement range from shallow ground levels to hot water and rock that are several kilometers below the Earth's surface. This chapter gives a comprehensive comparative evaluation of geothermal energy utilization in the world, application ranges and types, recent trends, and country-based improvements. Furthermore, geothermal energy resources are classified based on geothermal source enthalpy. Finally, the advantages and disadvantages of geothermal energy resources are comparatively discussed.