Passage 2 Bubbles of the Future?
如何俘获发电厂排放出的二氧化碳？ 《新闻周刊》2009-11-25 049

[00:01]Bubbles of the Future?
[00:04]Carbon sequestration sounds like a perfect solution to America's energy misfortune:
[00:11]capture carbon dioxide emitted by power plants in the atmosphere
[00:16]and store it deep in the ground.
[00:19]But as the technology to perfect carbon sequestration advances,
[00:24]it continues to face an unpleasant source of opposition: environmentalists.
[00:30]From West Virginia to New Jersey to Germany,
[00:34]green groups are protesting carbon capture and sequestration (CCS) projects,
[00:41]citing concerns over safety and effect. They insist that accepting CCS
[00:47]only allows energy companies to "greenwash" an inherently dirty practice,
[00:53]giving those companies an excuse to avoid the painful
[00:56]but necessary switch to renewable energy sources like wind and solar.
[01:03]There are nearly 200 such projects in various stages of development around the world,
[01:10]according to the U.S. Department of Energy.
[01:14]The federal stimulus bill set aside $3.4 billion for CCS research, and the government
[01:23]has offered at least $8 billion in loan guarantees
[01:27]for coal-fired power plants that employ CCS technology.
[01:33]?Opponents of CCS, which include Greenpeace and the Sierra Club,
[01:39]insist that this particular approach to pollution lessening is cheating.
[01:45]By some estimates, current technology will require
[01:50]between 10 and 40 percent of a plant's power just to function,
[01:55]and there's no guarantee that the carbon will stay still.
[01:59]If even a fraction of injected CO2 leaks out from underground storage sites,
[02:05]it could trigger a chain of chemical reactions that would cause poisons
[02:11]to the water supply, before eventually making its way back into the atmosphere
[02:16]where it would continue to warm the planet.
[02:20]And the technology might not be ready for large-scale deployment until 2030—
[02:26]about 15 years too late to avoid the worse effects of man-made global warming,
[02:34]according to many experts. Better to invest that money in renewable energy,
[02:39]opponents argue, than to waste it improving coal-fired power plants,
[02:44]which will presumably be obsolete in the coming decades anyway.
[02:49]Those are all valid concerns. But, as CCS proponents point out,
[02:55]more than two billion tons of domestic CO2 emissions come from existing coal-
[03:01]fired power plants. That accounts for half of total U.S. annual CO2 emissions.
[03:09]So even if we never build another coal-fired plant again,
[03:14]any hope of tackling climate change will require us to deal with the emissions
[03:20]from those existing plants, advocates say.
[03:24]"Obviously, we'd rather see more energy efficiency and more renewable energy,
[03:31]" says Natural Resource Defense Council (NRDC) scientist George Peridas.
[03:38]"But I think we have to be realistic. I haven't seen any convincing evidence
[03:45]that we're going to completely eliminate the use of fossil fuels in the coming years,
[03:51]so we have to figure out how to eliminate—or at least reduce—emissions."
[03:57]The opportunities are particularly ripe in some countries,
[04:01]where electricity consumption has shot up in the recent years.
[04:06]The countries still meets about 60-70 percent of their energy needs with coal,
[04:13]making them some of the world's largest emitters of CO2.
[04:19]According to a recent NRDC report, lower labor, material,
[04:25]and fuel costs will make CCS cheaper in the countries. Higher concentrations of CO2
[04:33]and natural geology contributive to carbon storage
[04:37]would also lower the cost of CCS projects in the regions.
[04:42]While CCS still has a way to go before it's ready for large-scale deployment,
[04:49]it might not take as long as opponents imply.
[04:52]Earlier this year Energy Secretary Steven Chu wrote in the journal Science that
[05:00]"widespread deployment of CCS can begin in 8 to 10 years." For example,
[05:06]amine  cleaning—where chemicals are used to separate CO2 from natural gas
[05:12]and hydrogen—has been used since 1930 to remove CO2 from the air aboard submarines
[05:20]and spacecraft. Experts say the technology is robust, proven,
[05:27]and ready to be tested on a larger scale for CO2 capture from coal-fired plants.
[05:34]And in the past year, scientists at Columbia University have made significant progress
[05:41]absorbing CO2 out of the air with the use of synthetic trees.
[05:47]Opponents remain unconvinced. "To combat climate change, the scale of CCS operations
[05:55]would need to be tremendous," says Greenpeace spokesperson Emily Rochon.
[06:02]"We have a lot left to learn about CO2 storage, and the corporations in charge of
[06:09]such projects aren't always acting in the most responsible manner possible."
[06:16]It's true that without more large-scale pilot projects people won't know for certain
[06:23]how safe or effective CCS is. But some early research looks promising enough to justify
[06:32]further study. For example,
[06:35]a 2005 report by the International Panel on Climate Change (IPCC)
[06:40]found that if CCS projects were properly sited and regulated,
[06:48]geological reservoirs could retain 9 percent of the carbon injected
[06:53]by CCS for hundreds to thousands of years. Studies show that the CO2
[07:00]will react with some elements in rocks to form calcium carbonate,
[07:04]essentially making the carbon part of the rock itself.
[07:09]And some experts believe that if proper limits were observed,
[07:15]liquid CO2 could be injected into the deep sea or the ocean floor
[07:21]without adversely impacting the local ecosystem,
[07:24]offering a potential reservoir for hundreds of billions of CO2.
[07:29]While CCS is expensive, there is no reason to believe that
[07:36]this technology won't follow the same trend as wind and solar—
[07:41]as the scale of projects increases, cost reductions will become apparent.
[07:48]American Electric Power, the nation's largest electricity producer, seems to think so.
[07:55]The company recently spent $73 million to improve its coal-
[08:01]fired "Mountaineer" power plant in New Haven, West Virginia,
[08:06]with wells and a small chemical factory that can covert CO2 into liquid
[08:12]and then inject it 8,000 feet underground. The plant now captures
[08:17]about 1.5 percent of its own emissions. But the company told The New York Times in September
[08:26]that if Congress passes a law controlling CO2 emissions, it would move to capture more—
[08:32]as much as 90 percent more—of the CO2 emitted from the Mountaineer plant. Duke Energy,
[08:40]a plant under construction in Edwardsport, Indiana, has been designed
[08:45]with extra space to allow for eventual improving with CCS equipment.
[08:51]But Duke will wait for Congress to act before the company begins any actual CCS projects.
[08:59]"We need to know what the price of carbon is going to be
[09:02]before we make any long-term capital plans," says Duke Energy spokesman Lew Middleton.
[09:11] The climate-change bill passed by the House of Representatives
[09:15]on June 26 requires all coal plants given permits after 2020 to use CCS
[09:23]when they begin operating, and all plants approved after 2009 to improve within five years.
[09:31]The Senate version of the bill, which is expected to be taken up in 2010,
[09:36]sets emission standards for coal-fired plants approved after 2009 but does not pass CCS.
[09:45]Proponents of CCS hope that if an international agreement
[09:50]on reduction targets is made in Copenhagen, companies might be compelled to work
[09:56]across borders on technology transfer. It won't be a remedy for difficulties,
[10:01]but at least it's a start.