Do geothermal heating projects set off earthquakes?
Published: 25 January, 2010, 12:43
Edited: 26 January, 2010, 11:07
TAGS: Natural disasters, SciTech
While the question the title of this article poses might seem like something from out of a Bruce Willis sci-fi action movie, geothermal drilling triggering seismic activity is very much the stuff of reality.
At least according to engineers from around the world, who recently studied a seismic event which occurred in Landau in der Pfalz, Germany. Some experts attributed the minor, 2.7-magnitude earthquake to the “enhanced engineered geothermal system (EGS)” that is providing heat and energy to the city. But engineers working inside the facility claim that the accusations are false. In their humble opinion, the shaking of the ground beneath their boots was nothing more than the routine geological activity according to the rules of Mother Nature.
Geothermal technology is derived by tunneling deep into the Earth’s underground in order to tap into water that is naturally warmed by the earth’s own heat. The water is then pumped up to the surface where it is used as energy to drive turbines that then generate electricity. EGS drilling tech however, goes much deeper into Earth. The massive drills bore through the bedrock and soil to depths of up to 10 kilometers. The enhanced drilling technology seeks to fracture the deep embedded rock and then pull out the heated water, bringing it up to the surface.
The major benefit of the geothermal energy is that, unlike oil or natural gas, it runs clean and is a sustainable green energy source. But does drilling for the energy cause earthquakes?
According to the earthquake experts at the US Geological Survey, seismic events occur when the stress that builds up from underground fault lines is suddenly released. The resulting “shaking of the ground caused by an abrupt shift of rock along a fracture in the Earth,” is what is known as a fault. While deep geothermal drilling is intended to unlock the potentially limitless reserves of heat and heated water from the Earth’s depths, it is the fracturing of the rock that has some engineers concerned about upsetting the Earth’s seismic inclinations, especially if the drilling is occurring too close to a seismic zone.
In a recent article drafted for ENR.COM, a popular trade magazine for engineering professionals, engineers opposed to the proliferation of EGS drilling are claiming that “fracturing the deep rock can cause earthquakes if the fracturing is too close to an active seismic fault zone.”
But Jefferson Tester, an MIT chemical engineering professor, believes that concern over serious earthquakes due to engineered geothermal drilling are unfounded. He backs up his beliefs by pointing out that the oil and natural gas industries have been drilling and fracturing the deep rock for decades without yet triggering a serious seismic event. “Yet” being the key word here.
However, according to Renewable Energy World.Com, it’s these very same engineering professors and experts who have no choice but to admit that “small seismic events known as microearthquakes have been recorded and monitored in the immediate vicinity of some injection sites. These usually have Richter magnitudes of 2 or 3 and are ordinarily imperceptible to people unless they are quite close to the epicenter.” What’s more, it is said that these microearthquakes, although triggered by geothermal drilling, pose no real “significant hazard” to surrounding buildings and infrastructure, be they homes, roads, bridges, commercial high-rises or, as in the case of Landau in der Pfalz, Germany, power plants.
Optimistic professors like Tester who defend geothermal drilling in order to tap into the Earth’s radiant core, are combating the naysayers by publicly cautioning the world against “unbalanced reports”. It is his professional opinion that, despite the microearthquake that occurred in Germany and another in nearby Switzerland, the intensity of the tremors caused by drilling is not “alarming” enough to be considered a damage-causing earthquake.
But one overriding question looms large: how inevitable is it that a so-called microearthquake might one day chain-react into a major earthquake of devastating proportions? With EGS tech becoming more popular and more deep holes being drilled down into the subterranean depths and more bedrock fractured unnaturally, only time and Mother Earth know the answer.
Vincent Zandri for RT
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Like "Art Dawn" wrote, these activities can most probably cause small local quakes, but it also may very well be that they can help release tensions and create bigger ones. However, quakes so big that they are a notable problem for humans are built up by nature, and those forces have to be unleashed sooner or later. In other words, I dont see this is a big problem (but it of course needs research). Geothermic energy has a lot of potential... to bad its so expensive to build:O
Wow, this reminds me of Rosanne Roseannadanna, the creation of comedian Gilda Radner. Rosanne would greatly misunderstand something she was clueless about, rant about it for a while, then realize she her error and say, "Never mind." In this case, not only does the author get it wrong about "drilling", but also confuses this issue about geothermal electricity generation with geothermal heating. *Buzz* Wrong! Geothermal heating (also called geoexchange, so folks like you don't get confused) uses the steady temperatures found within a few hundred feet of the surface as a place to dump excess heat from the air in a building during hot periods, and to warm air in the building during cold periods. By contrast, EGS wants (in a cost-effective way) to widen existing fractures in hot, deep rock (thousands of feet deep) so that water from the surface can be heated and brought back up to run steam turbines for electricity generation. Now on to the quakes. Geoexchange doesn't cause quakes. Drop the issue about "geothermal heating." It is ignorant. Also, **nobody reliable says drilling causes the quakes.** Drilling, or boring, or tunneling, or digging -- whatever word you can understand -- is just the act of making the hole down to the hot rocks. No quakes. It's the use of water later on that causes the quakes. This is due to thermal and pressure effects. The thermal effects are due to hot rock shrinkage from relatively cool water. The pressure effects are those familiar from hydrofracturing in the oil and gas industry, namely either from fracturing new rock, or nudging open existing fractures. These effects are expected, and can be managed. Regarding the Landau stuff, the quakes at issue are so small that the earthquake networks can't reliably locate them. The scattering of the locations are all over the map, so it's small wonder the Landau engineers don't think their project is causing it.












One sure and safe way the world could provide inexpensive heating and cooling to homes and businesses is by converting to geothermal systems. This system can be installed by drilling four {or more} wells approximately 220 feet deep and interconnecting the four wells {flexible pipe} and to a system that takes the solution through the heat pump of the heating/air conditioning unit. This system is closed loop {puts nothing into the ground} and saves a lot of money compared to gas or air to air heat pumps. Units probably last up to twenty or more years {the unit is inside, away from the weather}.The four wells mentioned here was for a home with about 2500 sqft of heated space. A smaller residence could get by with three wells. Want to save a lot of money on energy costs? Look into converting to geothermal.