Hydraulic fracturing in systems of geothermal energy utilization (EGS, HDR)

This work reviews possibility of using the heat from impermeable hot dry rock formations. Significant development in hydraulic fracturing technique in a last few years have a result in making accessible sources of energy from impermeable rocks, including hot dry rocks, which wasn't possible before. This paper presents the idea of utilization the EGS system which is based on forced and closed water circulation in a natural and permeable geological reservoir or in a reservoir, where the fractured zone was created artificially by for example hydraulic fracturing treatment. The article shows also an examples of recent EGS/HDR systems around the world.