According to a new study published in the Journal of Petroleum Science and Engineering on carbon capture and sequestration (CCS) by Michael Economides of the University of Houston and Christine Ehlig-Economides of Texas A&M University, clean coal is unlikely to prove a real solution to carbon emissions because the process of carbon capture and sequestration won’t prove feasible.
(EDITOR’S NOTE: It has been pointed out to us that many of these claims made by Dr. Economides may be overinflated or just plain spurious- a retort posted by NRDC here which we take very seriously. Because we don’t believe in just throwing blog posts down the memory hole, we want to give this big caveat, and watch for a further discussion on CCS from us.)
Proponents of coal have touted CCS as the future of coal in supporting efforts to combat global warming, but the technology remains unproven and has long faced skepticism.
CCS involves capturing the carbon dioxide given off during combustion and injecting it in either liquid or “supercritical” state into an underground rock formation to contain it from being disperse into the atmosphere.
The new study says that proponents of CCS have underestimated the amount of reservoir space required because the volume of carbon dioxide to be stored cannot exceed more than 1% of pore space, and perhaps much less, rather than the 1-4% used in most calculations. Specifically, the report states that:
“This will require from 5 to 20 times more underground reservoir volume than has been envisioned by many, and it renders geologic sequestration of CO2 a profoundly non-feasible option for the management of CO2 emissions.”
The mistaken calculations are due to the assumption that the CO2 can be injected into a reservoir formation at a constant pressure, the authors say. But in fact, pressure will vary, affecting the rate of injection. Excessive pressure could fracture the formation, says the study.
“In applying this to a commercial power plant, the findings suggest that for a small number of wells the area extent of the reservoir would be enormous, the size of a small U.S. state,” the authors say.
Several government-sponsored experiments in CCS are underway in various countries, including the U.S. The New York Times reported last week on a project in Germany that has been injecting carbon into a sandstone reservoir for the past 22 months and is attempting to monitor any leakage.
Note: Michael Economides, is the editor in chief of Energy Tribune and is a self-declared skeptic of global warming.
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I read the paper by the Economides that you are talking about. The erroneous basis for their calculations is that no wells are drilled to remove the ground water displaced by the stored carbon dioxide “carbon dioxide sequestration is not generally envisioned to be associated with any production of underground fluids,”
Their paper is proof if proof were needed that relief wells will be required for many geological structures. Others have discussed the issues that these relief wells might raise. See http://scienceblogs.com/highlyallochthonous/2010/02/carbon_capture_and_storage.php
Jem, you’re right, and there are numerous questions with then what to do: the brine removed from these aquifers is saltier than the ocean and would turn normal waterways brackish or be hazardous to plant growth if allowed to spill. You end up with a whole new waste stream, and the energy necessary to take enough salt out to dump the water in the ocean would turn the EROEI ratio so on its head that it makes the entire CCS issue seem economically unwise, considering especially the relatively cheap investments we can make in efficiency and renewable energy to make CCS irrelevant.
Andy, I don’t understand why you would need to take salt out before the displaced ground water goes into the ocean. You don’t have to put salt in when you discharge river water there, and after all the ground water is, as they say, just a drop in the ocean.
Jem, increased salinity in the estuaries and bays around Aransas, due in this case to drought and not enough riverwater reaching the estuaries, resulted in adverse impacts on species such as the blue crab and brown shrimp. (They must travel to find freshwater for sustainability, and if none is to be found, they can not survive.) This contributed partly or wholly in the deaths of the 8.5 percent of the whooping crane flock in the winter of 2008-09.
Yes, riverwater is discharged into the ocean, but this is a natural process and there are natural mechanisms in place to cope with the changing salinity, however under unusual conditions like massive flooding or drought, there are adverse impacts to the wildlife in the area. In most cases, this is a short term condition and the area can recover.
To discharge highly brackish waters into our waterways would have possibly devasting impacts on the wildlife along the bays and estuaries around the state from which those areas may or may not recover. This would impact both wildlife and the livelihoods of many living in the area.
Jem, I’m talking about taking deep brine aquifer water out from inland areas, not out under the ocean– that’s an issue in itself.
You know, there are some issues with this study, which were pointed out to me by some academics at UT and Scott Anderson over at EDF. We’ll be doing a more thorough analysis and posting something shortly. I still have reason to think we need to deal with these issues while setting up rules for carbon sequestration at the state and national level, but it seems this might not be as insurmountable as the Economides have stated.