Scientists Weigh Option of Burying Greenhouse Gases
Posted on: Friday, 9 May 2008, 03:05 CDT
In the fight against global warming, some scientists have chosen to focus on efforts to transform greenhouse gases into a solid form, making them able to be buried under the seabed.“If you can convert (the gases) to stone, and it's environmentally benign and permanent, then that's better," said Juerg Matter, a German scientist at Columbia University in New York who is working on a project in Iceland to turn carbon dioxide, the main greenhouse gas, to petrified stone.
One issue is that gases may leak, possibly because of an earthquake, with deadly consequences like the leak caused by a natural volcanic eruption of carbon dioxide from Lake Nyos in Cameroon, which killed more than 1,700 people in 1986.
Matter and U.S., French and Icelandic experts plan to inject 50,000 tons of the gas into basalt in a test starting in 2009.
Currently, the project is completely theoretical, as scientists are unsure of how long the process of changing the gases into stone may take.
"High pressure combined with low temperature results in liquid carbon dioxide that can in some cases be denser than sea water," said Kurt Zenz House, of Harvard University.
Other experts would like to see greenhouse gasses turned into a viscous liquid.
"High pressure combined with low temperature results in liquid carbon dioxide that can in some cases be denser than sea water," said Kurt Zenz House, of Harvard University.
The U.N. Climate Panel noted in a 2005 report that carbon storage could be a potentially efficient method of neutralizing global climate change . The process could contain up to one-third of all manmade carbon dioxide, but no commercial-scale power plant uses the technology yet.
The panel also said the penalty for emitting carbon dioxide would have to be stable at $25-$30 a ton to make carbon storage viable, which in turn would result in an increased cost of everything from electricity to steel as the price of slowing climate change.
Firms such as BP, Rio Tinto, E.ON, American Electric Power and StatoilHydro plan to work on capturing greenhouse gases and pumping them into porous rocks in shallower oil and gas reservoirs, or into disused mines or saline aquifers.
One commercial project in Norway actually began stripping carbon dioxide from natural gas at Sleipner field, where unusually high levels of carbon dioxide exist, in 1986.
"There have been no leaks," said Tore Torp, project leader at operator StatoilHydro. The gas, under pressure, is in a "supercritical" state between liquid and gas and wouldn’t become dangerous in the event of a cataclysmic earthquake, he said.
"In theory, if you had (a giant earthquake) a crack would be filled by the North Sea in seconds and would maintain the pressure down there," Torp said.
"The most important thing for safety is selecting the site. We would avoid the San Andreas fault" in California, he said.
Other similar projects are already underway in the U.S., Canada and Algeria.
However, proposals to send carbon dioxide into the world’s oceans, thus encouraging growth of carbon-absorbing algae, have been put on hold, according to Rene Coenen, office head for the London Convention which oversees dumping at sea.
"Our official advice is: 'don't start with it. Wait until we have more knowledge from the scientific side'," Coenen said.
Although water easily absorbs carbon dioxide, it also makes the seas more acidic, which some scientists fear could be a potential problem for shellfish and other creatures that rely on protective coats.
Carbon burial may be the best option to date, although some nations fear that it will encourage nations to continue their ties to fossil fuels.
"To my mind, if declared safe and acceptable, it is going to be an imperative in terms of an effective solution," said Yvo de Boer, head of the U.N. Climate Change Secretariat.
"If I look at some of the really huge coal-based economies around the world, like China, like India, like South Africa, like Australia, I don't really see how we can come to grips with climate change without using carbon capture and storage."
But scientists still don’t know how long a reaction capable of turning gases into stone could take.
"We do not know if these geochemical reactions ... will take 50, 100 or thousands of years," Matter said.
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Image Caption: An illustration of the Sleipner natural gas field in the Norwegian sector of the North Sea which pumps natural gas (green) to the surface and then reinjects excess carbon dioxide (blue) back into porous rocks for burial as part of a plan to slow global warming. The field, the longest-running commercial greenhouse gas burial project in the world, has pumped 10 million tonnes of carbon dioxide into the subsea reservoir since it started in 1996, equivalent to about a fifth of Norway's annual carbon dioxide output. (Credit STATOILHYDRO)
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Posted by STRANNIK on 05/10/2008, 10:25 Catastrophe on Lake Nyos in Cameroon in 1986 was not caused by volcanic eruption or earthquake ( http://www.nyos.lv/ ). Mechanism of leakage of the carbon dioxide from the terrestrial depths in a lake is not taken into account by J.Matter, U.S. and French and Icelandic experts, who plan to inject 50,000 t. of gas into basalt. In addition, is not taken into account the mechanism of leakage through the network of the microchannels, which instantly arises up in the mountain sort. The gas from the terrestrial depths is directed to the terrene through the network of the microchannels. This mechanism causes the outburst of coal and gas, sandstone and gas, potassium salts and gas in the deep mines. Therefore, very correct advice: 'don't start with it. Wait until we have more knowledge from the scientific side'. |
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