Hot dry rock contains a huge amount of geothermal energy and is one of the most important resources being explored in developed countries. The enhanced geothermal system (EGS) has been developed on the basis of hot dry rock utilization. EGS related science and technologies have been developed for decades, which are abundant in theoretical research and engineering practice. This paper reviews the developing courses of several important EGS projects, summarizing their successes and lessons, and provides a comprehensive discussion of the key scientific and technical achievements and deficiency, including new progress in high temperature geothermal systems. Prospect of their future development is predicted.

hot dry rock  /  enhanced geothermal system  /  engineered geothermal formation  /  hydrofracture  /  geophysics