Carbon sequestration is one of a number of proposed solutions to minimizing the ejection of carbon dioxide into the atmosphere and thus mitigating the growing climate change and warming currently taking place.
However according to Stanford geophysicist Mark Zoback there is a major point being overlooked in the furthering of these proposals.
Zoback believes that storing large amounts of carbon dioxide underground could trigger small to moderately sized earthquakes which, unlikely to hurt people or property, are still enough to break the seal on the storage of carbon, allowing it to seep back into the atmosphere.
Pumping large amounts of carbon dioxide in the form of liquid or gas into underground caverns which are located near or on ancient fault lines could cause them to quake earlier than they would have on their own (which will happen at each fault).
Such a quake would rupture the containment.
These ruptures would not necessarily cause the entirety of the carbon to be spewed back into the atmosphere at once, but more likely would cause a small crack to allow the carbon dioxide to seep back out over time, thus rendering the entire project futile and wasting money that could have been used better.
Zoback also points to another issue that has not been properly addressed, in his opinion; the number of sequestration projects needed to make the technology viable. According to his research, Zoback believes that the volume of carbon injected into the reservoirs annually would need to be the same as the original production of oil and gas each year, thus requiring thousands of injection sites around the world.
“Think about how many wells and pipelines and how much infrastructure has been developed to exploit oil and gas resources over the last hundred years,” he said. “You need something of comparable scale and volume for carbon dioxide sequestration.”
This number equates to some 3400 such project needed worldwide by the middle of this century to deal with the total amount of carbon dioxide we will be generating by that point in time.
“Finding that many ideal sites around the globe is not impossible, but it is going to be a tremendous challenge,” he said. And while some view the issues associated with injecting gas into the subsurface as mainly a technical challenge, Zoback thinks that challenge may not be an easy one to engineer around. “My main concern is to get these geological issues out on the table,” he said. “I want to get the discussion started.”
Source: Stanford University
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