The Extraction of Geothermal Energy from Hot Dry Rock: A Potential Green Energy Source

Heat stored in the earth’s crust is a potential resource of renewable and green energy to meet the global primary energy needs without producing any greenhouse gases. The majority of the geothermal resources are stored in the hot dry rocks (HDR) at a substantial deep depth as compared to hydrothermal resources. The present study illustrates an overview of the HDR resources available worldwide as well as in India. The article further discussed the available technologies to extract geothermal energy from HDR. A systematic review of the key technologies including enhanced geothermal systems (EGS) and single-well borehole heat exchanger systems is analysed in the article. A 2D numerical analysis of a single-well system with a coaxial wellbore heat exchanger has been carried out to extract thermal energy from the reservoir. In addition, the influence of various parameters on the system’s heat extraction capacity has also been investigated. The present work may aid in the development of novel enhanced geothermal systems and single-well systems with improved thermal performances.