Abstract
Summary On the way to Energy Transition, the Geothermal Energy Production (GEP) has accelerated in the regions of elevated subsurface temperatures recently. With groundwater temperatures reaching 103°C at 3000 m and natural hot springs, the Ily Basin in south-east Kazakhstan can become a good candidate for GEP if a sustainable approach is applied. The current study summarizes knowledge and showcases new data on Upper Cretaceous formation water in the eastern Ily Basin that is currently used mostly for greenhouse and fishfarm heating, and balneology. Water chemistry and tritium data show that recent meteoric waters are probably not the main source of recharge as it has been assumed for many years. If an average of 40 l/s of water production per well is assumed, a heat power of up to 1.5 MWel. can be harvested during cold time if a 10% efficient Binary Organic Rankine cycle is applied