Friday, August 31, 2012

Technology:

Going Deep for the Heat - A Norwegian Perspective (GeoExPro)

Geothermal energy is becoming an increasingly hot topic. Recent research suggests that even areas outside ‘high-temperature fields’ may be sufficiently warm to generate electricity.

The drilling rig at the 3,900m deep
Kirchweidach borehole in southern
Germany is capable of reaching 5,000m.
(Courtesy GeoExPro)
Beneath our feet there are rich reserves of heat and energy stored in rocks and groundwater. On average, with increasing depth, the temperature increases by around 3°C per 100m. In the upper surface layers the heat in the ground comes from the sun. A number of quantitative models from geothermal low activity areas (i.e. on stable platforms outside tectonic and volcanically active areas) show that at shallow depths down to a few hundred meters, mean annual surface temperature is the main factor controlling subsurface temperature. Geological variation in the underground, such as heat flow, heat production and thermal conductivity, first become significant around 1,000m and deeper below the surface.

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