An artist’s rendering of a power plant that would emit almost no pollution, turning coal into gas while capturing and storing carbon dioxide deep underground. (AP Photo/U.S. Department of Energy)
Is carbon capture the next energy fix?
ASK THIS | May 21, 2008
It would be nice if coal could be made clean; therefore, it will be made clean. That’s the coming political logic and we’ll be hearing a lot more about it. But first, writer Joseph Davis has a few questions that need looking into.
By Joseph A. Davis
During and after the coming election, Americans are likely to be hearing more about "carbon sequestration" as a miraculous energy fix that will allow us to burn coal and save the climate – having our cake and eating it, too.
As Barack Obama and Hillary Clinton campaigned in West Virginia and Kentucky, they spoke a lot about "clean coal" and not so much about global warming.
No wonder. Both are coal states. Coal is still the fuel used most to produce electricity in the U.S., and it is also the fuel whose burning produces the most carbon dioxide. Carbon dioxide is the biggest cause of human-induced global warming. Scientists often abbreviate it in policy discussions simply to "carbon."
In West Virginia, and on the U.S. Senate floor, politicians rarely say a negative word about coal – although they may speak of the need to limit carbon. When coal – which produces other environmental damages such as acid rain, smog, and mercury in tuna – is referred to at all, it is usually with the phrase "clean coal." The Bush administration has pushed range of "clean coal" technologies that offer the seductive hope that we can continue to burn coal without environmental consequences. And Congress, with the patronage of Democrats like Appropriations Committee Chairman Robert Byrd of West Virginia, has funded coal R&D to the tune of over two billion dollars a year.
Despite years of hype, hope, engineering, and subsidies, some of the clean coal technologies that were put forth as silver bullets in previous decades (combined cycle coal gasification being one) have yet to be much implemented on a commercial scale by electric utilities without government subsidies.
Today, on the campaign trail and in energy R&D circles, the big buzz is about something called "carbon capture and sequestration." The term refers to a suite of technologies many hope will capture the large amounts of carbon dioxide currently going up electric utility smokestacks and bury it underground or under the sea for a very long time. Sometimes the term is simplified to "carbon capture and storage," or simply CCS.
Clinton, Obama, and GOP candidate John McCain have all embraced carbon sequestration in various ways. So have the oil, coal, and utility industries. Environmental groups are divided and more skeptical.
There is even some rare skepticism from the news media. Chris Baltimore's May 12, 2008, story for Reuters stated: "Both candidates are playing up the ascendant role of commercially untested and so far economically nonviable ways of converting America's plentiful coal supplies into electricity without spewing massive quantities of heat-trapping greenhouse gases."
Some of the biggest enthusiasts for CCS technologies are oil companies. One CCS "poster child" is the Sleipner natural gas field in the North Sea, owned by Norway's StatoilHydro. It has been operating since 1996. While StatoilHydro is justifiably proud of the CO2-stripping technology there, it is not just altruistic. The company must remove the CO2 from its natural gas to make the gas commercially useful.
Oil companies would get some special benefits from CCS projects. They already own wells that could be used to inject CO2 deep underground. Moreover, injecting pressurized CO2 into oil-bearing rock formations that are nearing the end of their productivity is a way of squeezing a little more oil (and profit) out of them – an "enhanced oil recovery" (EOR) technique, in petro-jargon. Because oil companies may have a financial interest in CCS, their endorsement of it should be weighed with caution. It is, after all, an excuse to keep burning oil. The extra oil produced by pumping CO2 into aging wells will likely be burned by cars that release more CO2 to the atmosphere with their exhaust.
CCS technology, if it proves feasible at all, is more likely to be feasible only for large, centralized CO2 sources like coal-burning electric power plants, where the gas is more easily collected. These constitute an important but limited fraction of the total U.S. or world emissions. It is far less likely to be feasible for other, more diffuse CO2 sources like automobiles, which make up another important fraction of emissions. So CCS is hardly a complete solution.
CARBON CAPTURE TECHNOLOGY: ASK THIS
Q. What is the dollar cost of CCS? How much will it add to current energy costs? Who will pay for it? If the cost of burning coal increases because of CCS, will it be a better or worse energy bargain than conservation, solar, or alternative/renewable fuels?
Q. Will the federal government subsidize CCS technology for electric utilities? How would a federal subsidy distort free markets? Will it make less level the playing field on which various energy sources and fuels compete? Will it encourage the burning of coal? And if it does, what environmental and social consequences will result?
Q. What is the energy cost of the various CCS methods? Will we end up burning more fossil fuels in order to implement CCS? What will that do to the price of fossil fuels?
Q. Some economic analyses of CCS look more favorable because they factor in the benefits of enhanced oil recovery. Will that always be the case? Who will get the benefits of enhanced oil recovery -- the oil companies or the public? Will the resulting increased supply of oil be an unmixed blessing? Will additional uncaptured greenhouse gas releases result from burning the extra oil?
Q. If pressurized CO2 is injected into underground rock formations, will it stay there? How long? What are the chances it will eventually leak out to the atmosphere? Are formations that have been drilled repeatedly for petroleum or gas productions more likely to leak?
Some Background Resources on Carbon Capture and Sequestration
- Energy Department Carbon Sequestration Page
- Wikipedia article on "Carbon Capture and Storage”
- CBC News background feature on CCS by Robert Sheppard, March 9, 2007
- Intergovernmental Panel on Climate Change, Special Report on Carbon Dioxide Capture and Storage (2005)
- National Energy Technology Laboratory (U.S. Dept. of Energy), Carbon Sequestration Page
- Carbon Sequestration Leadership Forum
- U.S. Climate Change Technology Program CCS Page
- "Important! Why Carbon Sequestration Won't Save Us," Treehugger, July 31, 2006, by Michael Graham Richard
- "Carbon Dioxide Capture and Geologic Storage," Batelle Memorial Institute/Pacific Northwest Research Laboratory (DOE), lead author James J. Dooley
Nancy Graves - curious
05/25/2008, 04:40 PM
What type of impact if any will affect the water tables? Can this abundance of carbon be compined with other technologies to find alternative uses for it? Can carbon itself be processed to use as a source of energy?