Assessment of Super-Hot Rock Geothermal for Power Generation in Nigeria: A Review

Abstract Nigeria confronts a significant energy problem, with around 87 million individuals lacking electrical access and ongoing instability in the national system, highlighting an urgent necessity for varied, dependable, and sustainable energy sources. Super-hot rock (SHR) geothermal energy, an advanced technology utilizing resource temperatures over 400°C, offers a transformative prospect. SHR could generate five to ten times more energy per well than traditional geothermal systems, thereby greatly enhancing a secure, cost-effective, and carbon-neutral energy foundation. This study reviewed and evaluated Nigeria's geothermal potential from existing research papers carried out between 2015 – date using aeromagnetic and aero-radiometric method to assess Super-hot rock geothermal for power generation. The methodology incorporates review of geothermal features such as curie depth point, geothermal gradient, heat flow and radiogenic heat thereby calculating surface heat flow, mapping hydrothermal proxy using LithoRef18 Earth Reference Model, NGHF Model and IHFC measured Surface Heat Flow and correlating it with that of the existing studies. The datasets were integrated to detect and delineate potential SHR zones. The results show that SHF values derived from the LithoRef18 model and IHFC residual range from 24.3 to 116.8 mW/m2 and −102.5 to 60.3 mW/m2 respectively which indicate close agreement of heat elevation in the northeastern, northcentral and southeastern regions of the country. The estimated depth to the 450°C isotherm ranges from about 6.1 km to 28.7 km, indicating that super-hot rock conditions may occur within drillable depths of around 10 km in northeastern, northcentral and southeastern parts of the country. Based on the global super-hot rock resource framework, Nigeria's geothermal potential is estimated to be approximately 10,000 GW of power resource. The study highlights the potential of super-hot rock geothermal systems to contribute significantly to Nigeria's future energy mix. However, inconsistencies between measured surface heat flow data and the New Global Heat Flow model, largely due to data gaps, indicate the need for further geothermal investigations using additional geophysical methods to validate the results and reduce data uncertainties.