BURNING THE FUTURE: Coal is so cheap and plentiful that it will likely continue to play a large role in electricity generation, but in order to combat climate change the carbon dioxide produced will need to be sequestered.
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The Best Science Writing Online 2012
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The world emitted 25 billion metric tons of carbon dioxide (CO2) in 2003—more than one third, 9.3 billion metric tons, came from burning coal. The dirty rock provides half of the electricity in the U.S. and its role (or the nation's dependence on it) is likely to grow, according to a new report from the Massachusetts Institute of Technology. "It's cheap, there's lots of it and there's lots of it in places with high demand, namely the U.S., China and India," says co-author and M.I.T. physicist Ernest Moniz. "Sequestration," he adds, "is a key enabling technology for coal use in a carbon-constrained world."
Sequestration, as envisioned in the report, involves capturing the CO2 from coal-fired power plants, compressing it into a liquid and injecting it deep beneath the earth into old oil fields or saline aquifers. There, according to geologists, the CO2 would be trapped by sealing cap rock to prevent it from seeping back to the surface and into the air. It is relatively cheap to get it there, the report says. The difficulty is capturing it at the power plant without sapping too much energy or pushing electric costs up too high. For example, one 500-megawatt coal-fired power plant (there are the equivalent of 500 of these in the U.S. and China is building the equivalent of two of them each week) produces three million tons of CO2 annually. Adding carbon capture technology to that plant sucks up 40 percent of the power it can produce and adds at least 2.7 cents to the retail price of that electricity.
"If you capture most of the CO2 and sequester it for the 50-year life of the plant, you're talking about one billion barrels of supercritical CO2," Moniz says. "That's a pretty big reservoir."
To date, the largest sequestration project—the Sleipner gas field in the North Sea—slurps up one million tons of CO2 per year (11 million or so since inception) and relies on sonar to detect any major leaks. "So far, so good," says Howard Herzog, principal research engineer at M.I.T.'s Laboratory for Energy and the Environment. "The problem with Sleipner is it's not as instrumented as we would like."
In other words, it does not have the kind of in-place monitoring systems critical to understanding the true workings of liquid CO2 stored underground.
Nor is it big enough to help understand what would happen if even larger amounts of supercritical CO2 were pumped underground. In fact, it would take 3,600 projects of Sleipner's scale—which is the largest such project underway—to reduce current carbon dioxide emissions from coal by less than half, the report says. But even the small projects are already turning up surprises, such as the relative permeability of various rocks and the ability of CO2 to mix with saline and form carbonic acid, which eats away surrounding rock. And, of course, no one knows exactly how long the carbon dioxide could be contained. "The long-term, chemical fate of CO2 remains to be understood," Moniz notes. "It's like a mortgage. It gets us out of the problem in the 21st century, spreading it out over a longer time and not breaking the budget."
U.S. companies have already planned several demonstrations of such carbon capture and sequestration. Among the 25 projects authorized by the federal Department of Energy, First Energy plans to install a new carbon capture technology on its R. E. Burger power plant in Ohio and then partner with engineering firm Battelle to test pumping it 7,000 feet beneath the surface. But none of these projects is of yet sufficiently large scale and that, the report's authors argue, is because there is no cost associated with emitting CO2. "Right now, it's free to vent carbon dioxide to the atmosphere," says S. Julio Friedmann, a geologist and head of the carbon management program at Lawrence Livermore National Laboratory.
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8 Comments
Add CommentIf carbon sequeatration requires 40% of the electric power produced by the plant, this is a "no-win" strategy. I've worked as a consultant for fossil fueled plants, and know that the present SO2/NOX/Precipitator power /Ash Handling usage already requires 15% of the power plants output. If you add 40% more to this, the plant is using 55% of the energy it produces for internal requirements.
Reply | Report Abuse | Link to thisConsidering that coal fired plants only have a 40% efficiency to start with because they must first convert the chemical energy of coal to steam energy, then the steam to electrical energy; the carbon sequestration process is a losing proposition.
CO2 is good, not bad. We all benefit from more of it in the atmosphere, especially farmers and foresters. Why?
Reply | Report Abuse | Link to thisPlant growth stops at 200 PPM in the atmosphere.
Plant growth is optimized at 1000 PPM; commercial greenhouse owners invest good money in CO2 generators to raise greenhouse concentrations toward the optimum to increase the productivity of their fixed growing area.
In particular, increased levels of CO2 enable plant growth in drought conditions.
150 years ago CO2 concentration in the atmosphere was 285 PPM, now it's 385 PPM. It's like free airborne fertilizer in the atmosphere.
Increased levels of CO2 have significantly increased crop and forest yields over the last century. If environmentalists truly wanted a greener planet they would want more, not less, CO2 in the atmosphere.
Warmer temperatures are generally good, not bad. Most of us benefit from warmer temperatures, especially farmers and foresters. Why?
Warmer temperatures increase growing seasons and produce more consistently successful crops from year to year.
Warmer temperatures reduce heating fuel consumption in the winter. This is a very big deal today because world oil production peaked three years ago and will begin a permanent decline in two years. That is why the cost for all fuels is going through the roof. Fuel costs will only decline during economic down turns, like we are experiencing now.
Warmer temperatures two thousand years ago enabled the rise of the Roman Empire. The subsequent cooling period resulted in the fall of the Roman Empire and the social and economic decline into the Dark Ages. The next warm period one thousand year ago ushered in the Renaissance. Today's warm period enabled the rise of the United States. The Dalton (type) Minimum the sun is now entering will dramatically affect us all by virtue if it's impact on crop yields in the northern and southern hemispheres.
The cooling we are now experiencing, together with declining availability of carbon based fuels, will dramatically affect our lives and our economy. Taxing the use of carbon based fuels will make matters much worse. Taxing carbon is like leaning into a right hook. It's a quick way to end the fight.
Warming is caused principally by the sun, not by elevated levels of CO2.
Energy from the sun drives our climate, not CO2.
Energy from the sun is modulated by the oceans and the atmosphere to produce our weather. Changes in climate are drive by long-term changes in the sun's radiative output and magnetic field strength. Google: Fairbridge Solar Inertial Motion (SIM) for a sense of how this works physically.
The principal green house gas is water vapor. It provides 95 percent of our greenhouse warming effect. Without it the earth would be a ball of ice. As a greenhouse gas, CO2 is a distance fourth being methane and nitrous oxide, which produce most of the remaining 5 percent of greenhouse warming. CO2's concentration in the atmosphere is four one-hundredths of one percent (.04 %). That's roughly equivalent to the thickness of the floor wax on your community's high school basket ball gymnasium, compared to the distance from the floor to the ceiling. The quantity and warming effect of CO2 in the atmosphere is negligible.
The two trends described above have done more to "green" the planet over the last several decades than anything humans have done to motivate that change. Both trends are now headed south, naturally. Solar activity is declining and will continue for the next few decades, cooling the earth about 2 degrees (C) in this quiescence period. The sun has just emerged from several decades of very high activity, which has warmed the earth by about one half degree(C). CO2 levels will naturally decline as carbon fuels production, particularly oil, begin their long decline. World oil production has been flat for three years. We are all going to meet our Kyoto targets whether we plan to or not. The environmentalists should be pleased. The rest of us won't.
Clean Coal ie with carbon capture and storage, cannot work on the required scale because of the extra energy demands and lack of safe but gargantuan storage spaces. Add to that the coal price doubling every 18 months or so.
Reply | Report Abuse | Link to thisThe biggest challenges of carbon capture for the U.S. coal industry pertain to scale and cost, both of which are huge. Researchers at MIT estimate that if less than two-thirds of the carbon dioxide from U.S. coal plants were captured and compressed for storage, the collective volume to be stored underground "would about equal the total U.S. oil consumption of 20 million barrels per day."
Follow the Link:lincenergy.us/
Carbon sequestration is enhanced oil recovery (EOR) paid for by U.S. taxpayers. Ask the oil companies if they're going to pay for monitoring buried CO2? Ask them if they're going to obtain private insurance? Ask them how much oil/gas they get from these old bore holes, and in some cases new bore holes? Ask the fossil fuel folks how much their drilling methodologies contribute to the formation of potentially destablizing methane hydrate?
Reply | Report Abuse | Link to thisAsk them how many hundredes of billions it will cost to take over your neighborhood lands to lay their thousands of miles of pipes to transport their CO2 ? and how much the manufacture of pipelines would cost?, and who would pay for breaks and spills as well as the repair/clean-up?
At what cost are we willing to continue to create incentives for stripping more mountains, and building more ponds/dams for coal sludge which eventually become rivers, polluting ground water, and agricultural land.
Clean coal is an oxymoron. If the Administration insists on pursuing this then they will, tragically, embark on a "fools errand."
The perfect clean, renewable and inexpensive substitues for coal as a fuel are hydro-kinetic energy and industrial hemp. Flowing water has been used for over 5,000 yrs. as a source of power. We have the technology, we invented the modern damless technology with which to extract energy from flowing water, visit www.gcktechnology.com, these turbines are being used in S. Korea, Brazil, and India.
They are not used here because the fossil fuel folks at the DOE have been told to limit funding for hydro-kinetic demonstration projects. Rejection of these turbines hinges on the fact that they can replace coal and all other energy sources. The real problem is they have very low profit piotential since they operate without coal, gas or oil.
The case for using hemp as a renewable energy source is severely constrained because of the anti-pot movement among the religio-cons who made their hysterical claims in 1937 that America would become addled by marijuana. Well, 100,000,000 users so far have tried it and the nation still functions after all these years. We need to legalize pot, so that we can achieve energy independence, and at the same time save our forests, mountains, ground water, etc.
Kannabis has been traced back 6,000 years to the Indo-Semitic-European language family base of the Summerians and Accadians. It is the longest surviving root word. Yet we cut off our noses to spite our faces by thwarting legalization of hemp cultivation.
Um... well... we solve the lack of oil problem by using captured CO2 to help grow alge to make more oil.
Reply | Report Abuse | Link to thisThis whole sun bit is neat... how come I've never heard of it?
I like carbon capture and sequestration very much. It should be required immediately of all new coal fired power plants. This is exactly what we need to ensure that solar energy is the cheapest form of electricity available.
Reply | Report Abuse | Link to thisFace the facts: clean coal is a myth.
Reply | Report Abuse | Link to thisClean coal is a dirty lie. www.thedirtylie.com
Reply | Report Abuse | Link to thisMountaintop removal is destroying rural appalachia, from extraction to combustion coal is not the answer to our long-term energy needs.