Lithium enrichment in high-enthalpy geothermal system influenced by seawater, Indonesia

Lithium holds significant importance in energy storage and can be extracted from geothermal water, making it an additional resource to traditional mining. Combining lithium extraction from geothermal water with electricity generation from geothermal energy offers a compelling strategy to address future energy challenges. Situated in Southeast Sumatra, Indonesia, Way Ratai has considerable geothermal potential and is known for its hot springs. This study primarily aims to characterize lithium enrichment within the Way Ratai geothermal system. Water samples from various sources (one spring, seven hot springs, one well, and seawater) were analyzed for cations, anions, trace elements, and isotopic composition. The results show that Way Ratai is an old geothermal system with sodium-chloride water, where lithium enrichment is attributed to interactions between water and rocks, with some influence from seawater. The discrepancy between calculated and observed magnesium (Mg) concentrations suggests a pre-heating mixing process between rainwater and seawater. The reservoir rock in Way Ratai is mostly andesitic, with temperatures ranging from 182^o to 227^oC. This study enhances our understanding of thermal water characteristics, reservoir temperatures, and water origins in high enthalpy geothermal systems, offering valuable insights into lithium enrichment in coastal geothermal regions.