Geothermal Power Generation

AbstractGeothermal energy is the heat energy generated from radioactive decay of minerals and stored in the Earth. Theoretically, total geothermal resources are more than adequate to supply all human energy needs for many years. However, so far only a small portion of geothermal energy has been extracted and used either directly as a heat source or converted to electricity. Often significant drilling and exploitation costs make the energy conversion process unfeasible.Geothermal industry has been significantly developed since the first commercial geothermal plant was built in 1904 in Italy. Geothermal sources are in different forms including dry hot steam, hot water, and hot rock. Depending on the characteristics of each geothermal resource, different types of geothermal plants have been designed and installed. Single‐ or double‐flash power plants are the most common plants for hot water geothermal resources.As the technology develops and more renewable energy policies are introduced, the levelized cost of geothermal power decreases. Future technology developments, renewable energy initiatives, and availability of other sources of energy are expected to further reduce the cost of geothermal power.This article provides an overview of geothermal history and focuses on reviewing the principles of geothermal energy conversion systems. Some statistics of major past and current geothermal power plants are given; however, as new geothermal power plants become online in future, care should be taken when referring to these statistics.