Enhancing the hot water yield in low enthalpy geothermal systems in Sri Lanka

Global interest in low-enthalpy geothermal systems has emerged as a result of rising fossil fuel prices as well as a desire to reduce CO 2 emissions. However, in equatorial regions such as Sri Lanka, geothermal energy remains often unexploited, mainly because there is no need for space and district heating. The comparatively low temperatures and discharge rates of natural thermal springs are also insufficient for industrial or agricultural applications. In Sri Lanka, hot water bearing faults are obscured by clay filled depressions of very low hydraulic conductivity. The clay limits the natural discharge rates of the hot water and leads to heat loss as well as mixing of thermal water with cold shallow groundwater. Identifying the near-surface hot-water bearing faults underneath the clay layer enables specifically targeted drilling operations. Bypassing the clay layer increases discharge rates and heat flow, hence enabling industrial and agricultural usage of the geothermal waters. Thus, comparably simple measures can put the geothermal resources of Sri Lanka to good use.