fracture conductivity tuning (IMAGE) Penn State Caption To produce more efficient geothermal systems, researchers have proposed a process called the fracture conductivity tuning technique. This approach involves preventing cold water and allowing hot water to flow through fractures — like the ones pictured here — in rock deep underground. Credit Provided by Arash Dahi Taleghani Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. No derivatives or adaptations of the work are permitted. License CC BY-NC-ND Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.