Geodynamics Limited has successfully completed the first half of its “Proof of Concept” hot fractured rock (HFR) program to extract hot water for electricity generation from granite buried beneath the Cooper Basin in NE South Australia. Difficult drilling conditions were discovered in the target granite when the Habanero-1 well penetrated permeable sub-horizontal fractures at more than 4,000m depth. The well was completed at 4,421m. The static rock temperature at the bottom of the well is 250°C. The overpressures (>5,000 psi) assisted in the development of the world’s largest zone of artificially enhanced permeability, a volume of rock more than 0.7 km defined by more than 11,700 microseismic events during the injection of 20Ml of fresh water into the granite fracture network. The horizontal heat exchanger is more than 2km NS, 1km EW and 300m thick. During its development it showed no evidence of upwards growth towards the sedimentary cover at around 3,700m. The development so far indicates that there is a very good potential for economic energy extraction in the future. This potential has been considerably enhanced by the discovery of the overpressures in the granite fracture network which could add a large convective heat component into the original design which was based purely on conductive heat transfer within the heat exchanger volume.