Implementing CCS at coal-consuming plants is imperative if the carbon dioxide concentration in the atmosphere is to be kept at an acceptable level. The 1992 United Nations Framework Convention on Climate Change calls for stabilizing the atmospheric CO2 concentration at a “safe” level, but it does not specify what the maximum value should be. The current view of many scientists is that atmospheric CO2 levels must be kept below 450 parts per million by volume (ppmv) to avoid unacceptable climate changes. Realization of this aggressive goal requires that the power industry start commercial-scale CCS projects within the next few years and expand them rapidly thereafter. This stabilization benchmark cannot be realized by CCS alone but can plausibly be achieved if it is combined with other eco-friendly measures, such as wide improvements in energy efficiency and much expanded use of renewable energy sources.
The Intergovernmental Panel on Climate Change (IPCC) estimated in 2005 that it is highly probable that geologic media worldwide are capable of sequestering at least two trillion metric tons of CO2—more than is likely to be produced by fossil-fuel-consuming plants during the 21st century. Society will want to be sure, however, that potential sequestration sites are evaluated carefully for their ability to retain CO2 before they are allowed to operate. Two classes of risks are of concern: sudden escape and gradual leakage.
Rapid outflow of large amounts of CO2 could be lethal to those in the vicinity. Dangerous sudden releases—such as that which occurred in 1986 at Lake Nyos in Cameroon, when CO2 of volcanic origin asphyxiated 1,700 nearby villagers and thousands of cattle—are improbable for engineered CO2 storage projects in carefully selected, deep porous geologic formations, according to the IPCC.
Gradual seepage of carbon dioxide into the air is also an issue, because over time it could defeat the goal of CCS. The 2005 IPCC report estimated that the fraction retained in appropriately selected and managed geologic reservoirs is very likely to exceed 99 percent over 100 years and likely to exceed 99 percent over 1,000 years. What remains to be demonstrated is whether in practice operators can routinely keep CO2 leaks to levels that avoid unacceptable environmental and public health risks.
Technology Choices
Design studies indicate that existing power generation technologies could capture from 85 to 95 percent of the carbon in coal as CO2, with the rest released to the atmosphere.
The coal conversion technologies that come to dominate will be those that can meet the objectives of climate change mitigation at the least cost. Fundamentally different approaches to CCS would be pursued for power plants using the conventional pulverized-coal steam cycle and the newer integrated gasification combined cycle (IGCC). Although today’s coal IGCC power (with CO2 venting) is slightly more expensive than coal steam-electric power, it looks like IGCC is the most effective and least expensive option for CCS.
Standard plants burn coal in a boiler at atmospheric pressure. The heat generated in coal combustion transforms water into steam, which turns a steam turbine, whose mechanical energy is converted to electricity by a generator. In modern plants the gases produced by combustion (flue gases) then pass through devices that remove particulates and oxides of sulfur and nitrogen before being exhausted via smokestacks into the air.
Carbon dioxide could be extracted from the flue gases of such steam-electric plants after the removal of conventional pollutants. Because the flue gases contain substantial amounts of nitrogen (the result of burning coal in air, which is about 80 percent nitrogen), the carbon dioxide would be recovered at low concentration and pressure—which implies that the CO2 would have to be removed from large volumes of gas using processes that are both energy-intensive and expensive. The captured CO2 would then be compressed and piped to an appropriate storage site.
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Add CommentCCS is but one inconvenience of burning coal. A second and more important one is ressource depletion. We are apparently not going to leave the slightest scrap of fossil energy sources for our descendants. Coal, when developing countries start consuming it, will not last more than 150 years. This is the time foresters envisage before harvesting an oak tree! Whatever happened to foresight in economic planning. What has happened to the notion of strategic stocks set aside for the future. Just as our world economic system is collapsing, climate change and ressource depletion will cause havoc as of now, if only we will recognise the truth of our carbon gluttony.
Reply | Report Abuse | Link to thisYet we do have a choice : Biochar technology parallel with energy efficiency laws based on a carbon tax of $30 per ton of CO2 emitted.
see www.EPRIDA.com Good coal burning is no coal burning...
BORON
Reply | Report Abuse | Link to thisBoron, boron, boron.
Reply | Report Abuse | Link to thisForget sequestering CO2 from the coal fired power plants. They generate over 35 tillion pounds of CO2 every year worldwide. This is enough to build a mountain of solid dry ice a mile high. There is nowhere on earth to bury this much, even if you could transport it to the holes. The CO2 that coal generates weighs over 3 times as much as the coal itself. Think of the coal trains you see going across America.
Reply | Report Abuse | Link to thisIt is really obvious this story was written in the dark ages of knowledge concerning the realities of carbon capture and storage. In the intervening two years, we have seen rapid escalation of costs in every conceivable way from construction costs of the power plants themselves to severe escalation of projected costs to build and operate CCS facilities. In fact, the University of Kentucky' Center for Applied Energy Research made a presentation last December that showed CCS will result in a 25-40% "parasitic" energy cost in a new power plant.
Reply | Report Abuse | Link to thisIt is really obvious this story was written in the dark ages of knowledge concerning the realities of carbon capture and storage. In the intervening two years, we have seen rapid escalation of costs in every conceivable way from construction costs of the power plants themselves to severe escalation of projected costs to build and operate CCS facilities. In fact, the University of Kentucky' Center for Applied Energy Research made a presentation last December that showed CCS will result in a 25-40% "parasitic" energy cost in a new power plant.
Reply | Report Abuse | Link to thisSo on the bottom of the page, new coal is extremely expensive when compared to alternatives for generation but with new regulations coming for disposal of coal combustion waste and some form of increased fees for releasing carbon, either through Cap and Trade or the more easily understood carbon tax, coal is rapidly becoming a pariah instead of a panacea of our energy future.
Finding ways to use a lot less electricity should be just as high on our priority list. I just reduced my heating bill 60%. If I used electricity for heat that would have been a huge reduction in electric load. The real question is how to motivate a few hundred million Americans to weatherize?
Reply | Report Abuse | Link to thishttp://biodiversivist.blogspot.com/2009/03/weatherization-nation-how-i-reduced-my.html
Finding ways to use much less electricity should be just as high on the priority list. I just did an experiment on my house to see how much I could lower my heating bill with weatherization (60%). If I heated with electricity I would have made a serious dent in energy use. I documented how I did it below:
Reply | Report Abuse | Link to thishttp://biodiversivist.blogspot.com/2009/03/weatherization-nation-how-i-reduced-my.html
Although I am not a subscriber, or even a regular reader of SciAm, I find it appalling that they would even consider publishing an article of this nature considering there is very little science contained and is mostly the opinions of a select few. Science deals in FACTS. Items of discussion that can be proven experimentation, either in a lab or in the real world. Although science and history have proven that climate change is real, there has been NO real data that human activity is the cause. Also, as reputable scientists are beginning to discover, increased CO2 levels in the atmosphere are not the cause, but rather the effect, of increased average global temperatures. I refer you to a recent testimony by a Princeton physics professor, William Happer, to the US Senate Environment & Public Works Committee concerning global warming and the "scare" that the media is presenting to the public.
Reply | Report Abuse | Link to thisCCS poses many other threats to the public aside from those noted here. How many millions or trillions of tons of natural resources (i.e. coal, gold, other MINED products) are we going to risk sterilizing if we pump the ground they are contained in full of high pressure CO2?
England is proving that cap and trade does not work. It was implemented there several years ago and all that has occurred is the skyrocketing of power bills. There has been NO significant reduction in CO2 emissions since the implementation. Although we as homeowners may be able to reduce our personal power consumption to a certain degree, industry typically has a fixed baseload that they can do very little to reduce significantly. All of these costs will be passed on to the consumer. From a rise in utility bills to an increase in goods sold.
While I do agree that we as a country need to be exploring alternative forms of energy, we do NOT need to shut the door on coal. "Green" energy such as wind and solar can barely meet the baseload demand in some areas and will never be able to meet peak demand since their generation capacities are so very limited and variable. As I can see it, only nuclear, and possibly hydrogen, have the potential to meet those needs and replace coal as a form of energy.
And by the way, just in case you're wondering, yes, I live in WV, halfway between 2 of the largest mountain top removal jobs in the state. I am a coal miner and dang proud of it!
With the aticipated improvement in CCS as we build coat fired power plants, the United States will become the world's largest energy producer and at the same time, lower our carbon footprint. We will get back our manufacturing capabilities and regain our proper position as an economic giant. The anti-coal green hysterical movement will bankrupt us if we let them. Our government and our coal and power companies should wise up and get to work by using our tremendous coal reserves where we are the leaders in the world. Coal should be the new green giant, and those who say no deserve two black eyes for their blind stupidity.
Reply | Report Abuse | Link to thisWe have more coal than any other country in the world. We can figure out clean, carbon-dioxide free, non-poluting methods of utilizing this asset or we don't deserve to be the economic giant we should be. Germany utilized coal to power their war machine during the latter part of World War II even while we were bombing the hell out of them. What are we, a bunch of quitters?
Reply | Report Abuse | Link to thisWe have more coal than any other nation in the world. If we can't figure out clean, pollution-free, carbon-dioxide free methods to extract, transport and utilize this great asset, then we don't deserve to recapture our role as an economic giant. Germany used coal to power their war effort during the latter years of World War II even as we were bombing the hell out of them. What are we, a nation of quitters?
Reply | Report Abuse | Link to thisBy David G. Hawkins, Daniel A. Lashof and Robert H. Williams as can, heat hands on a fire.
Reply | Report Abuse | Link to thisNobody extinguishes it(him) is going to.
Yours Obama is surrounded with the fools, from the point of view of interests of the citizens, because do not react to the useful letters to address the president.
I personally informed to your president, that in Russia the way of transformation of a thermal energy of an environment in mechanical job and electric power is open.
Informed, that this invention is not necessary for Russia and has received from administration of the country the sanction to interaction with the foreign investor.
To the officials, which surround Obama - to spit on all declared Obama of the initiative on preservation of an environment! The answer no from your wise men.
How to concern to yours Obama, which holds in the environment of the fools - the assistants!?
By David G. Hawkins, Daniel A. Lashof and Robert H. Williams as can, heat hands on a fire.
Reply | Report Abuse | Link to thisNobody extinguishes it(him) is going to.
Yours Obama is surrounded with the fools, from the point of view of interests of the citizens, because do not react to the useful letters to address the president.
I personally informed to your president, that in Russia the way of transformation of a thermal energy of an environment in mechanical job and electric power is open.
Informed, that this invention is not necessary for Russia and has received from administration of the country the sanction to interaction with the foreign investor.
To the officials, which surround Obama - to spit on all declared Obama of the initiative on preservation of an environment! The answer no from your wise men.
How to concern to yours Obama, which holds in the environment of the fools - the assistants!?
VTMINER, you are an idiot. I know you must have children. People with your mentality usually have a lot of children. You work hard everyday in destroying the very environment they will have to live in tomorrow and you can care less if they have clean water to drink, clean air to breathe, or non toxic land to live on. You do not see the destruction you leave in your wake or the deadly chemicals that is invading your children's body everyday. Coal is a destructive force and it is killing the land and the people who live around it. Wake up and smell the death you create around your family every day. Yes, I know you are proud to be a coal miner and I believe you must also be proud in being an idiot, after all -- The Hills Of West Virginia Have Eyes --.
Reply | Report Abuse | Link to thisConsider the technology outlined in this article before going too far down the path of burying this potential feedstock:
Reply | Report Abuse | Link to thishttp://www.technologyreview.com/Energy/18582/
Spreading innuendo and not substance that's what spreading. You don't tell the whole story of using coal as a fuel source.
Reply | Report Abuse | Link to thisMany large industries and generating companies have not been vigilant and using modern stack emissions or what is best called pollution control equipment. Most coal fired plants use antiquated very old technology emissions controls. So pollution and stack emissions is passed along to some other location many, many miles down wind of the plant. You know the old addage, the solution to pollution is dilution.
But, coal is cheap, and the difference in profitablity and going into the red is using coal firing to balance the books. Coal gets the least amount of funds to clean it up, nuclear gets the most funding.
Coal is affordable to all consumers, and other than hydraulic generation coal gets the shaft. Nuclear will bankrupt industries with ever increasing pricing. Subsidizing nuclear and so called Green energies is a pie in the sky liberal plan. In time that liberal plan "has" to be fully paid, and that is people, you will pay huge amounts of monthly billing to be "Green". Industries have to plan years in advance to forecast "if" they are going to be viable. Most heavy industries are forecasting doom, they know that if the Green Plans get further promoted they will not be viable in the North American market, so closing down plants is there only option.
All you Green people who want to follow this stupidity, there are NO green jobs, only unemployment. You've priced energy for bulk users, combined with excessive laws and regulations on fossil fuels by forging ahead on "carbon taxation or carbon trading" to kill North American heavy industry.
I say invest in coal fired plants smartly, install emission reduction equipment, promote clean coal technology, and make less restrictions on heavy industry.
Environmentalists who support the Green industry stuff don't even work in the industry, all they are is a bunch of whiners, and doomsayers.
I say invest in your neighbors job, keep energy affordable, and promote North American heavy industry.
We have too, we're going broke.
CLEAN COAL.
Reply | Report Abuse | Link to thisLOL
)*( cooling tower or an ass your choice.
Dukebaker-3 times the weight?You don't get something from nothing.Where is all this extra mass coming from?
Reply | Report Abuse | Link to thisjack.123
Reply | Report Abuse | Link to thisIf C stands for the carbon in coal and O2 stands for the oxygen in the air then 3 times is approximately right. C+O2 weighs a lot more than C by itself.
C has an atomic weight of 12 and O has an atomic weight of 16. Hence O2 has an atomic weight of 32.
CO2, the result of combining the carbon in coal with oxygen, will weigh 44 in atomic weight. 44 divided by 12 will give about 3.8 that is to say CO2 weighs 3.8 times more than C all by itself .