Numerical investigation of the impact of fracture aperture anisotropy on EGS thermal performance

•Natural fractures exhibit geometric anisotropy.•Fracture surfaces in a perpendicular flow configuration have a higher tendency for favorable thermal performance than fracture surfaces in a parallel flow configuration.•The flow-wetted surface area and volumetric flowrate contribute to the amount of heat extracted from an enhanced geothermal system.•High geometric anisotropy results in a high difference in thermal performance between the perpendicular and parallel flow configurations.