Friday, April 24, 2009

Dangers of CO2 Sequestration in Sandstone Formation

From the New Scientist Print Edition, March 27, 2008 article by Fred Pearce -

"Coal produces around three times its own weight of CO2. This will all have to be pressurised, liquefied and moved to a site where it can be interred at depths of a kilometre or more, where the pressure will ensure that it stays liquid.

How secure would these burial grounds be? Opponents of CCS schemes recall the disaster in 1986, when a million tonnes of CO2 belched from the bottom of Lake Nyos in Cameroon. Being denser than air, the gas formed a blanket that asphyxiated some 1700 people. Though the event was entirely natural, it has left a potent image of what could go wrong. As Bert Metz, co-author of a 2005 report on CCS by the Intergovernmental Panel on Climate Change, says: "Public acceptance is a possible show-stopper if things are not done properly."

Geologists don't dismiss the possibility of a catastrophic release, after an earthquake perhaps. But they see slow seepage as at least as important a concern. To prevent climate change, CO2 has to be stored safely for millennia. Even a leakage rate of 0.01 per cent a year - a suggested industry standard - would see almost two-thirds of the gas gone within 10,000 years. The legal question of who has long-term responsibility for stored carbon is also unresolved, and it could prove as convoluted a debate as that over nuclear waste. No surprise, then, that next to designing a capture plant, assessing the leakage threat is the major research focus for CCS."

Susan Hovorka of the University of Texas, Austin, the project's principal investigator,points out, " geologists will be under pressure to find burial sites close to power plants, where the rock formations may be less than perfect. "We know how to recognise an excellent site," she says. "But we need confidence about when to screen out sites that are too risky." She also admits there is no method yet for deciding how much CO2 a particular rock formation can absorb before leaking, and how to spot if things are going wrong

The furthest-advanced project is a test site at which engineers have injected 1600 tonnes of CO2 into a sandstone formation known as the Upper Frio on the Gulf coast of Texas. The rock, which once contained oil, is now flooded with salt water. An early report on the Frio project, published in the journal Geology by Yousif Kharaka of the US Geological Survey, points to a possible danger of storing CO2 in formations like these. The CO2 has acidified the brine, allowing it to dissolve metal-oxide minerals in the rock, and this, Kharaka says, might eventually create tunnels in the cap rock through which CO2 might escape.

An article about the Greenville, Ohio project, can be found by clicking you read it, make sure you note the words used over and over......"TEST" TESTING"
In their own words from that site -

"The Midwest Regional Carbon Sequestration Partnership (MRCSP)1 is one of seven partnerships established by the U.S. Department of Energy (DOE) to test the feasibility of geologic sequestration."

"The carbon dioxide would be stored permanently deep below the ground under the plant."

This statement suggests that it would all be contained right there, not migrate off their property.

"The site has geology that is likely to be suitable for carbon dioxide storage. The Mount Simon
Sandstone, which underlies the site, is the largest potential geologic reservoir for carbon
sequestration in the Midwest. The test will enable geologists to learn more about the capacity of this deep formation, which underlies parts of Ohio, Kentucky, Michigan, Indiana, and Illinois and is estimated to have the capacity to store a large fraction of carbon dioxide emissions from large coal fired power plants in the Midwest for many decades."

"By the completion of the project in 2018, the injection site will be closed and will be returned to near the original condition that existed prior to implementation of the geologic storage demonstration test."

I ask you, HOW can the site be returned to "near original condition" after 1 million metric tons of supercritical CO2 is permanently injected into the ground......... who monitors this site afterwards? Who has the legal liability should YOUR home be damaged or destroyed in an earthquake as a result of this 'TEST" "EXPERIMENT"?

"CO2 measurement and monitoring approaches for subsurface processes have yet to be proven at the temporal and spatial scales relevant to geologic sequestration. While the current capabilities are not an impediment to undertaking CCS, monitoring and verification approaches will likely benefit from lessons learned through demonstration and early projects."

(Benson S. and L. Myer, 2008, “PIER white paper on Monitoring to Ensure Safe and Effective Geologic Storage of Carbon Dioxide.,” Assessment of Geologic Carbon Sequestration in California, E. Burton and R.Myhre, Eds. PIER Energy‐Related Environmental Research, C‐500‐2008‐009.)

"the ability to assess carbon sequestration risks will improve with time and with experience. Especially in the early years, each sequestration site is not just a place to get rid of CO2; it is also an experiment that will provide valuable data for use in future sequestration efforts." (