Geothermal energy potential of basement hot springs: Case study of Ulu Slim (Perak, Malaysia)

Abstract

Interest in geothermal energy as a clean, renewable and stable source of energy is mounting as part of the strive towards carbon emissions reduction and transition away from fossil fuels. Hot springs occur in locations of active hydrothermal systems that may have exploitation potential and this paper assesses the potential of Ulu Slim hot-spring, the warmest of some 60 basement hot-springs reported across Peninsular Malaysia. Available data and analogue inferences i.e., hot-spring surface temperature and flowrate, applicable ranges in geothermal gradients, geothermometer indications of source temperature, hydraulic head differences related to surface topography, indicative and tentative fault and fracture dimensions, geometry and distribution, are summarized and supplemented by conceptual hydrodynamic- and thermodynamic-model calculations to bracket the possible range in key subsurface parameters like source depth and geometry and properties of the fracture system that control extractable heat. Results are then used in another mathematical model that simulates the heat-extraction and electric power potential of hypothetical wells drilled into the hot-spring source, supported by injector wells (re-injecting the cool waste stream from the powerplant). Model outcomes suggest that premature cooling due to fluid circulation through narrow fracture/fault corridors is a significant risk. Overall, study results suggest that utilizing the geothermal heat of hot springs like Ulu Slim for electric power generation may be not so straightforward. Maybe the search for attractive geothermal locations should be less guided by hot-spring locations but instead, driven by proximity to infrastructure and electricity demand.