The Geothermal Resources of Iceland

Abstract

Presently about 2/3 of the primary energy use in Iceland comes from geothermal resources. Almost 90% of all houses in the country are heated by geothermal energy. The installed geothermal power from high temperature geothermal resources has increased from 202 MWe in 2004 to 572 MWe at the end of 2008. Continued development is envisaged. The current estimate of the potential geothermal power in Iceland is a volumetric assessment from 1985 and has not been updated yet. There it is expected that 3500 MWe of geothermal power could be produced from the energy stored within the upper 3 km in known Icelandic geothermal fields. Environmental and economical constraints might reduce this by half. In a similar way, it is expected that the technically accessible geothermal potential outside the known high temperature geothermal fields is of the order of 40,000 MWe. However, the above numbers are expected to be much higher if the emerging technology of unconventional geothermal systems could be applied. These include evolution of EGS systems and utilization of supercritical geothermal fluid deep in the volcanic systems. Recent research shows that temperature in the range 200-500°C can be expected at 3-6 km depth everywhere beneath Iceland and these depths are now easily accessible by present day drilling technology. Thus, application of EGS technology could open up huge resources of geothermal energy in Iceland in addition to the conventional resources and create synergies with the EGS development elsewhere. In addition to this, about 600 km long sections of the central Mid Atlantic Ridge are within Icelandic waters at sea depths less than 2500 m where very high temperature can be reached at shallow depths below the sea-bottom. It is considered possible that sometime in the future, technological advancements could allow profitable generation of electricity from the huge heat resource beneath the oceanic ridges.