Deep geothermal energy: physical principles, current technology implementation, economics, and environmental evaluation

This paper gives a general overview of the development of deep geothermal energy, the current technology implementation, the environmental and economic evaluation of geothermal energy system. Typical geothermal systems are introduced respectively including dry steam power plant, flash power plant, binary system, EGS technologies as well as heating system. Some new ideas and models for exploitation are gathered. It’s pointed out that utilizing geothermal fluid step by step (such as applying combined system) can improve the efficiency significantly because of the lower reinjection temperature. For the evaluation of geothermal systems, the emission intensity is nearly zero while it’s noteworthy that the toxic chemical may be released and geological disasters may be caused during drilling and hydraulic fracturing. Geothermal energy is competitive in electricity market due to the low running costs, and the installed capacity of geothermal energy will continue to increase.