Thursday, February 24, 2011

Geothermal in Newcastle! Quake!

24 Feb '11: Just to distinguish deep geothermal from shallow geothermal, this project in Newcastle UK is drilling down to levels where there is real heat coming up - water at 80 degs C, hot enough to make a hot cup of tea -
  The heat we are using in ground source heat pumps goes nothing like as deep and the contribution from the deeper heat below is too small to quantify. The GSHP's heat comes from Solar heat falling on the soil during the years and soaking in to many metres deep. Thus a ground source heat pump can run out of easy warmth if the soil around the building is heavily shrouded by trees or other buildings.
  Interesting to see a counter article in the website claiming that a significant fraction of recent earth tremors are not 'acts of god', they result from man's interference - ultra deep mining (perhaps as deep as 5,000 metres), fracturing of the rock, pumping gas under high pressure into the rock.... some of these activities are believed to have cause tremors or quakes. A 1989 quake in (of all places Newcastle, New South Wales) was thought to result from deep mining, and caused damage at the surface more costly than the value of the coal extracted in the life of the mine.
  As reported in Live Science website some projects may have been abandoned once the risks of earthquake became known. An earth tremor in Basle in 2006 is still causing legal action, years later, due to the damage at ground level.
  Even though we all know that there is plenty of heat down there, it is clear that we have to be careful about how it is extracted.
(Many thanks to the good people of the website for finding me those references, a lot friendlier than the Navvy - trolls.)

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