From hot rock to useful energy: A global estimate of enhanced geothermal systems potential

Abstract

This study demonstrates the theoretical, technical, optimal economic and sustainable potential of enhanced geothermal systems (EGS) globally. A global estimate of EGS is presented in a 1°×1° spatial resolution. Constructed temperature at depth maps are computed for every 1 km thick layer, from 1 to 10 km. Multiple factors such as surface heat flow, thermal conductivity, radioactive heat production, and surface temperature are involved, and obtained from various sources and assumptions. The global EGS theoretical potential is assessed. Available heat content is then estimated using technical constraints for the temperature equal to or higher than 150 °C for any 1 km depth, and presented as thermal energy and electrical power capacity. The EGS optimal economic potential is derived from the optimum depth and the corresponding minimum levelised cost of electricity. The global optimal economic potential in terms of power capacity is found to be about 6 and 108 TWe for the cost years of 2030 and 2050, respectively. If economic and water stress constraints are excluded, the global EGS potential can be as much as 200 TWe. Further, an industrial cost curve is developed for the levelised cost of electricity as a function of EGS technical power capacity. The findings indicate that around 4600 GWe of EGS capacity can be built at a cost of 50 €/MWh or lower. A method is applied to measure the sustainable geothermal resource base. The obtained sustainable potential is found to be 256 GWe in 2050. Results are presented on a country basis and globally.