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Filling a summer news hole with news on earthquakes

Filling a summer news hole with news on earthquakes Natural gas drilling near Shreveport, Louisiana (source: flickr/ danielfoster437, creative commons)
Alexander Richter 17 Jul 2013

Recent news on earthquakes and a correlation to geothermal activities seem to fill a news hole in the summer and is only distracting on a larger debate on shale gas and fracking by the oil and gas industry.

The never ending story of scientific studies proving that geothermal activities cause earthquakes continue and it seems the recent wave of articles is simply another run at the same topic in this case likely to fill a news hole over the summer period.

While I am not arguing scientific arguments for geothermal activities being the cause to some seismicity, one has to keep in mind that geothermal power plants and development thereof is in most cases to be found in areas with either ongoing or formerly volcanic activities, which coincidentally can be found in tectonically active areas, such as the St. Andreas gap in California, but essentially all along the western coast of the Americas and along the “Pacific Ring of Fire”.

So for people in those areas concerned about earthquakes they have to understand they live in areas with natural earthquakes and this is part of the life. A certain level of fear is understandably, and the geothermal industry likely needs to do a better job in addressing those concerns, but the story is a bit more complex.

This newest wave of “earthquake news” and “earthquake proof” comes at a time when the oil and gas industry faces a lot of bad press on their activities in the natural gas business, mostly due to activities of “fracking”.

In France, fracking by the oil and gas industry is banned, but a recent announcement that 4 geothermal projects in the country have been allowed to do some stimulation work as part of planned EGS development, brought the oil companies to a boil. They are now demanding getting the same treatment as geothermal.

If now in the U.S. a new debate is started on earthquake caused by geothermal activities one has to keep in mind that this already happens in areas with constant natural earthquake activities. Re-injection of fluids is known to cause some seismicity, as described in this recently reported study, in Iceland and elsewhere. If this is actually really recognizable more than would be the case under normal – non geothermal plant operations levels – is a question, which probably cannot be answered as clearly.

The European Geothermal Energy Council (EGEC) recently published a fine document that describes the difference between EGS (enhanced or engineered geothermal systems) and shale gas, that have certain similarities, but also some differences.

EGEC describes the general objective of extracting for both as an energy source as similar. “Geothermal and Shale gas methodologies have some similarities: Both use stimulation techniques based on high pressure water injection with the objective to generate a high permeability to extract as much mass flow as possible.”

“Shale gas is locked in rock in a dispersed form (typically in rock with low permeability, in sedimentary basins),
without fluid. EGS targets semi-permeable rocks with some discontinuities and where a fluid already exists.
Because geothermal power production uses rocks with at least a low permeability it requires stimulation but
with lower pressure injection.” To see the EGEC report see: this link.

Overall, the stimulation done by geothermal is less intrusive, needs fewer wells and not constant stimulation efforts. So seismic events can be monitored and controlled much better. There is also less pressure applied for EGS stimulation work.

So while there clearly might be some impact, it is not as extensive as some people make you believe. So the whole debate about earthquakes through geothermal has to be seen in connection with the current political debate around shale gas and possibly efforts by the oil and gas industry to discredit geothermal for the sake of their activities.

This is a shame, as the oil and gas sector could be a large player in the geothermal sector, and actually already is with most of the oil and gas service firms active for geothermal development.