Iceland deep drilling project, exploration of supercritical geothermal resources

The Iceland deep drilling project (IDDP) is a long-term research and development program aimed to improve the efficiency and economics of geothermal power generation by harnessing deep natural supercritical hydrous fluids obtained at drillable depths. Producing supercritical fluids will require drilling wells and sampling fluids and rocks to depths of 3.5 to 5 km, and at temperatures of 450-600degC. The current plan is to drill and test a series of such deep boreholes in Iceland; at the Krafla, the Hengill, and the Reykjanes high temperature geothermal fields. Investigations have indicated that the hydrothermal system extends beyond the three already developed target zones, to depths where temperatures should exceed 550-650degC. Occurrence of frequent seismic activity below 5 km indicates brittle and permeable rocks. A deep well producing 0.67 m³/sec steam (~2400 m³/h) from a reservoir with a temperature significantly above 450degC could yield enough high-enthalpy steam to generate 40-50 MW of electric power. This exceeds by an order of magnitude the power typically obtained from conventional geothermal wells. Being able to harness such unconventional geothermal resources is of great importance for many areas in the world where green sustainable energy is needed.