Globally, the amount of electricity that could be technically generated by EGSs for less than USD 300 per megawatt-hour (MWh) using thermal resources within 8 km of depth is about 300 000 exajoule (EJ). This is equivalent to almost 600 terawatt (TW) of geothermal capacity operating for 20 years – exceeding the technical potential of conventional geothermal by almost 2 000 times.

Compared with other renewable power generation sources and technologies, geothermal has the second-largest technical potential for electricity-generating capacity after solar PV, and almost three times that of onshore wind and more than five times that of offshore wind. Given the average capacity factors of each renewable technology, geothermal’s 4 000 petawatt-hour (PWh) (15 000 EJ) of technical potential for annual generation is about 150 times current global annual electricity demand. Furthermore, this estimate relates to electricity generation only, while in practice additional waste heat could also be used for district heating or industrial processes. 

Geothermal energy potential increases as you tap into deeper and hotter resources. The technical potential for geothermal electricity at depths of less than 5 000 m is an estimated 42 TW of power capacity over 20 years of generation (21 000 EJ), while potential at 5 000-8 000 m exceeds 550 TW (280 000 EJ).

At a depth of 2 000 m, only a limited number of countries with favourable geothermal conditions can effectively harness high-temperature heat for electricity generation. Conditions for geothermal electricity generation generally become more widely plentiful at greater depths: for instance, almost every region has technically suitable resources beyond 7 000 m. 

Almost one-fifth (115 TW) of EGS power potential is in Africa, which also has the largest untapped conventional geothermal potential. In fact, even tapping less than 1% of this potential would meet Africa’s electricity needs in 2050 in all IEA scenarios. As a country, the United States is assessed to have the world’s largest technical enhanced geothermal capacity potential, with about one-eighth of the global total (over 70 TW). Even at a depth of 5 km, US technical potential is over 7 TW, seven times more than the country’s total installed power capacity today. China has the second-largest potential, accounting for almost 8% (50 TW) of the global total. The Chinese government has identified the provinces of Hainan, Guangdong and Fujian as potential enhanced geothermal sites owing to their favourable geological conditions. 

ASEAN countries together represent about 15% (125 TW) of the global technical potential for EGS power generation, with Indonesia and the Philippines in the lead.

Meanwhile, Europe, where several countries have been conducting EGS research and demonstrations since the 1970s, accounts for less than 5% (40 TW) of global potential – but this already represents 35 times Europe’s current total installed electricity capacity. In India, potential for conventional geothermal is highly limited; however, at a depth of 5 km the country’s potential grows considerably to around 14 TW. Within Gujarat State, the eastern coast of Andhra Pradesh and the central Son Narmada Fault Zone are among the key areas for geothermal power generation development.