OXYFUEL: In September 2007 the oxyfuel combustion chamber is lifted into place at the Schwarze Pumpe power plant in Germany--one of the first power plants in the world to capture carbon dioxide.
Image: Courtesy of Vattenfall
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Editor's Note: This is the first in a series of five features on carbon capture and storage, running daily from April 6 to April 10, 2009.
Like all big coal-fired power plants, the 1,600-megawatt-capacity Schwarze Pumpe plant in Spremberg, Germany, is undeniably dirty. Yet a small addition to the facility—a tiny boiler that pipes 30 MW worth of steam to local industrial customers—represents a hope for salvation from the global climate-changing consequences of burning fossil fuel.
To heat that boiler, the damp, crumbly brown coal known as lignite—which is even more polluting than the harder black anthracite variety—burns in the presence of pure oxygen, a process known as oxyfuel, releasing as waste both water vapor and that more notorious greenhouse gas, carbon dioxide (CO2). By condensing the water in a simple pipe, Vattenfall, the Swedish utility that owns the power plant, captures and isolates nearly 95 percent of the CO2 in a 99.7 percent pure form.
That CO2 is then compressed into a liquid and given to another company, Linde, for sale; potential users range from the makers of carbonated beverages, such as Coca-Cola, to oil firms that use it to squeeze more petroleum out of declining deposits. In principle, however, the CO2 could also be pumped deep underground and locked safely away in specific rock formations for millennia.
From the International Energy Agency to the United Nations–sanctioned Intergovernmental Panel on Climate Change (IPCC), such carbon capture and storage (CCS), particularly for coal-fired power plants, has been identified as a technology critical to enabling deep, rapid cuts in greenhouse gas emissions. After all, coal burning is responsible for 40 percent of the 30 billion metric tons of CO2 emitted by human activity every year.
"There is the potential for the U.S. and other countries to continue to rely on coal as a source of energy while at the same time protecting the climate from the massive greenhouse gas emissions associated with coal," says Steve Caldwell, coordinator for regional climate change policy at the Pew Center on Global Climate Change, a Washington, D.C. think tank.
Even President Barack Obama has labeled the technology as important for "energy independence" and included $3.4 billion in the $787 billion American Recovery and Reinvestment Act for "clean coal" power.
Today three types of technology can capture CO2 at a power plant. One, as at Schwarze Pumpe, involves the oxyfuel process: burning coal in pure oxygen to produce a stream of CO2-rich emissions. The second uses various forms of chemistry—in the form of amine scrubbers, special membranes or ionic liquids—to pull carbon dioxide out of a more mixed set of exhaust gases. The third is gasification, in which liquid or solid fuels are first turned into synthetic natural gas; CO2 from the conversion of the gas can be siphoned off.
Some U.S. utilities have already built or upgraded plants to capture CO2, which they either store or sell. The 180-MW Warrior Run coal-fired power plant in Cumberland, Md., already captures 96 percent of its CO2 emissions to sell for use as a fire extinguisher or dry ice. The Kingsport power plant in Kingsport, Tenn., has been capturing CO2 since 1984 to sell to carbonated beverage makers.
The U.S. Department of Energy (DoE) has invested more than $3 billion since 2001 to fund multiple CCS projects being conducted by seven regional partnerships, including demonstrations of ammonia capture technology at the massive coal-fired Pleasant Prairie power plant in Kenosha County, Wisc., and the R. E. Burger plant in Shadyside, Ohio. The Obama administration may even resurrect the FutureGen project—a 275-MW IGCC power plant that would capture 90 percent of its emissions; the Bush administration had canceled it because of spiraling costs (which may have been miscalculated). And the DoE has offered at least $8 billion in loan guarantees for coal-fired power plants with CCS.
Australia and China have demonstrated that postcombustion capture is possible in pilot plants. At Loy Yang Power Station in Victoria, a pilot plant run by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) will capture 1,000 metric tons of CO2 a year; the Australian research organization has also collaborated with China's Huaneng Group to use an amine scrubber to capture CO2 from a co-generation power plant in Beijing and then sell it.
But although multiple projects around the world examine or test aspects of CCS, few of them have been connected to a full-size power plant: one producing on average 500 MW and upward of 10,000 metric tons of carbon dioxide a day—the core of the emissions problem. And the few that have been are either venting the CO2 after capturing it or selling it, instead of taking the next step and storing the greenhouse gas underground.
"It makes nine metric tons of CO2 per hour at full load," says Staffan Gortz, Vattenfall's CCS spokesman, of the $100-million CCS demonstration boiler at Schwarze Pumpe. But he acknowledges that "we don't have a storage site yet."
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17 Comments
Add CommentExisting coal fired power stations will be difficult to retrofit to capture CO2, so this means it will take many decades to sequester such CO2, maybe too late for the climate. Oil and gas can be pyrolysed, the hydrogen burnt and the carbon captured as charcoal and the charcoal sent to specialised power stations where the CO2 can be sequestered. Biomass can also be pyrolysed, but pyrolysis is receiving scant research funding...
Reply | Report Abuse | Link to thisWhy are these moronic idiots still pushing this deadly fossilized garbage waste that is destroying our planet...our air, our health, our water, our land? Start mass producing electric cars, build a couple of geothermal power plants and lets get the hell away from all kind of fossil fuel. These are very dangerous and destructive people, and they should be put in prison for the rest of their life.
Reply | Report Abuse | Link to thisI love these headlines "Climate Change Catastrophe"
Reply | Report Abuse | Link to thisOnce we get brains wrapped around the fact that CO2 is not bad, will not cause an end to the world as we know it, will not curve your spine and will not lose the war for the allies, a lot of things will get easier.
Now, if you object to coal due to other pollutants, then by all means push to get the nasties cleaned up. Just don't believe for a second that CO2 is a pollutant.
Signed:
Carbon-based life form
NO, NO, NO. Carbon Capture and Storage is not the answer! It is treating the symptoms and not the disease.
Reply | Report Abuse | Link to thisI recently wrote a blog looking at this same issue:
http://blog.mapawatt.com/2009/03/13/carbon-capture-and-storage/
Basically, we can take BILLIONS and spend it on burying something underground, or we can spend that money and put it to good use while taking the same amount of CO2 out of the air.
Carbon Capture is short term decision making and thinking that is mainly being promoted by the Coal Industry. Would you really call Carbon Capture a sustainable practice?
The world's emissions of the main planet-warming gas carbon dioxide will rise over 50 percent to more than 42 billion tonnes per year from 2005 to 2030 as China leads a rise in burning coal, the U.S. government forecast on Wednesday. China's coal demand will rise 3.2 percent annually from 2005 to 2030, the Energy Information Administration said in its International Energy Outlook 2008. --Reuters, 26 June 2008
Reply | Report Abuse | Link to thisAny carbon diet strategy would be dependent upon clean coal:
"The vast majority of new power stations in China and India will be coal-fired; not "may be coal-fired"; will be. So developing carbon capture and storage technology is not optional, it is literally of the essence." --"Breaking the Climate Deadlock," Tony Blair, June 26, 2008
But, Vaclav Smil, an energy expert at the University of Manitoba, has estimated that capturing and burying just 10 percent of the carbon dioxide emitted over a year from coal-fire plants at current rates would require moving volumes of compressed carbon d ioxide greater than the total annual flow of oil worldwide -- a massive undertaking requiring decades and trillions of dollars. "Beware of the scale," he stressed."
On the other hand, a world-class geneticist has his team working on improving the efficiency of microbes to convert compressed CO2 into CH4 at an industrial pace. This technology would be ideal for profitably converting the CO2 from dirty coal-fired power plants into fuel to suppliment natural gas supplies.
"Still as ambitious as ever, (Craig Venter) just announced at the TED conference: "We have modest goals of replacing the whole petrochemical industry and becoming a major source of energy, we think we will have fourth-generation fuels in about 18 months, with CO2 as the fuel stock." What's this fourth-generation fuel he's talking about? Biofuel alternatives to oil are third-generation. The next step is life forms that feed on CO2 and give off fuel such as methane gas as waste, according to Venter." --"Geneticist Craig Venter Wants to Create Fuel from CO2," TreeHugger.com
Carbon Capture and Storage will be the National Missile Defense of the Obama administration -- a fruitless, expensive, search for a technology that even in the unlikely case it were to work exactly as designed would not address the larger underlying issues, and would not solve the real problem.
Reply | Report Abuse | Link to thisPut a price carbon emissions, and we'll have less of them.
I love reading the posts of eco-nutjobs:
Reply | Report Abuse | Link to this"...put in prison for the rest of their life"
Really, folks, CO2 is our friend.
I like to burn used car tires just to watch the pretty flames. The black sooty smoke is lovely. I'll stop if some one buys some carbon-credits from me. Only $100, a pop. There's my price on carbon emissions. Any takers?
p.s. I own and drive an SUV.
It's sad that Sci Am seems to embrace this nonsense. CO2 is not a pollutant nor is it or will it ever affect world climate. It only comprised 0.03% of the atmosphere and has risen to 0.036% over the last 200 years. Global warming has been occurring for 12000 years. It still is.
Reply | Report Abuse | Link to thisThe good news is that we don't have to sequester the 10 billion tons a year of carbon spewed by coal plants. Biomass can be easily converted into E-coal which can be burned in our existing coal plants without modification. The cost is actually cheaper than burning coal and you don't even need the expensive scrubbers to get rid of mercury and sulfur because the biomass doesn't have any. Biomass is carbon neutral and clean. www.newearth1.net
Reply | Report Abuse | Link to thisCan it really be cheaper to extract O2 from N2 in a plant's air supply than extracting CO2 from N2 in its exhaust? The boiling point of O2 is a hundred degrees lower than the sublimation point of CO2.
Reply | Report Abuse | Link to thisPlease explain, it may be too late?
Reply | Report Abuse | Link to thisCoal fired plants require retro fitting precipitators, and adding improved dust capture equipment. Most of these devices are from the freaking 1950's in technology.
As for actually damaging the planet that's a stretch. If anything its the rhetoric coming from all these eco green whackjobs who keep blowing hot air about climate change. Prove it first, then shut down the utility company equipment. Until then let the rest of us afford electrical power before you "Green" people put the price into the stratesphere.
Anything is possible given enough time and resources. But it is highly unlikely that carbon capture and sequestration will be practical on any large-scale basis. Building condom plants and distributing free condoms world-wide would be much cheaper and more effective in reducing CO2 emissions than the oxyfuel process and subsequent CO2 storage referred to in the article. Respectfully, Albert
Reply | Report Abuse | Link to thisTo make coal "clean", it would also have to be mined cleanly, without various highly dirty practices such as dumping mountain tops into valleys and streams.
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Reply | Report Abuse | Link to thisEntropy (not Energy) is the Issue
According to the Conservation of Energy Principle (The First Law of Thermodynamics), we can neither create nor destroy energy. This means we will always have as much energy as we ever had. So, how can we experience an energy crisis?
Our crisis develops from another law of energy: The Entropy Law. It states that energy use always results in some overall loss of availability, quality, or order. Physics characterizes such loss as an increase of entropy. This is where informed energy discussions begin.
The inevitable increase of entropy seems to have a slightly different character for each system under consideration. For example, heat always flows from the hotter to the colder body, never the reverse. Perfume molecules escape their container and spread throughout the room, but never gather back into the bottle of their own accord.
While heat is flowing, or perfume molecules are spreading, they can do work—are useful. Even after heat flows down its temperature hill, or the molecules spread out in a room, overall energy remains constant, but that energy is now unavailable for use--no good for doing work.
Entropy applies thermally, structurally, and environmentally. Just as a weight cannot supply any mechanical work once it reaches its lowest available level, thermal energy is not available for use after it falls to an ambient temperature. It simply becomes ‘waste’ heat, like car exhaust. Entropic disorder is commonly termed pollution.
There are various mathematical expressions for Entropy, such as S = k ln W (where k is a constant and W is the microstates per macrostate). Due to its broad, complex, and abstract formulations, some have rejected the Entropy Law—even deemed it an illegitimate natural principle because too ‘anthropomorphic’ (as if scientific laws had any other origin). Einstein, however, thought the Entropy Law was the one law that would never be overthrown.
Some have said that life transcends the Entropy Law, but no contradiction exists since the overall Entropy increase (system plus surroundings) still exceeds the entropy decrease of a structuring organism.
By extension of the Entropy Law, matter also becomes unavailable for use. High entropy copper junk (because dispersed in refuse dumps) can be too costly to recycle, both monetarily and environmentally, thus practically unavailable. Entropy’s economic decrements are developing beyond the control of today’s price mechanisms.
From an entropy perspective, economic growth is the progressive transformation of usable energy into unavailable energy. This means an overall decline in our environment—except that the sun’s outside gift of energy may compensate for this decline by driving the earth’s large-scale regenerative cycles (carbon, oxygen, etc). The sun’s finite input, however, can only compensate if economic activity’s entropy production is not too large.
All large-scale technical fixes such as ‘clean’ coal, nuclear, or corn-ethanol create quality (entropy) issues. Energy from coal results in acid rain, global warming, methyl mercury in food chains, and toxic, congesting particles in the air we breathe. Nuclear plants create radioactive waste in direct proportion to the energy produced—some of which (Plutonium 40) requires environmental isolation for hundreds of thousands of years. Nuclear decommissioning costs billions. Corn-ethanol production emits two to nine times the greenhouse gas emissions ‘saved’ by substituting it for gasoline.
Because of the high environmental costs we pay for creating high-quality (low entropy) energies such as electricity or hydrogen fuel, we should use them only where their quality is truly necessary. Coal-electric space heating and plug-in cars remain prohibitive.
The Entropy Law sets limits to the types of energy use humans can sustain. Since all earth-energized technological orderings result in an overall loss of order (even for pollution control devices and recycling), entropy compensating sources of energy must be external. Practically, this means the sun. Non-solar energy solutions become ‘uneconomic’ (if not snake oil) once price mechanisms factor in their entropy effects.
We can choose to assess and respect the Entropy Law’s implications, or we can continue to make energy policy in ignorance. A mix increasingly weighted toward low entropy solar applications is finally unavoidable. Reversible entropy is not merely a tree-hugger’s fancy; it is an ecological necessity.
For many energy applications, we have yet to determine the form, let alone the cost, of their attendant entropy (disordering). In the very big picture, however, specific calculations (the details) don’t matter. According to the entropy law, we either go (relatively direct) solar or decline.
A mathematical interpretation follows: The Entropy Law (Second Law of Thermodynamics) when applied to an overall system undergoing an irreversible (practical) energy exchange and consisting of a subsystem of interest in equilibrium with its surroundings is expressed mathematically as
dS(overall) =
dS(subsystem) + dS(surroundings) > 0
where dS is the attendant change in entropy.
The surroundings are taken large enough to form an unlimited reservoir. Thus, equilibrium is maintained with the system of interest. The above mathematical inequality states that the overall, proximate change in entropy (subsystem plus surroundings taken together) for any practical energy exchange is always positive. In other words, all earth-alone energy exchanges result in a net disorder.
Should external (solar) energy enter the overall system, the mathematical inequality may no longer hold. The net entropy can be zero or even negative. In other words, inputs of solar energy can compensate the otherwise inevitable entropy increases of our energy exchanges.
Here are a few examples of how an entropy-oriented analysis might expeditiously cull out technological proposals.
Aren’t hydrogen-fueled cars ‘ecological’ since they emit only pure water? An entropy analysis cuts immediately to whether a solar component is involved. If no solar component exists to negate the entropy that attends hydrogen production, storage, and handling, the overall effect is ecological degradation. Note the economy of approach here. An entropy analysis doesn’t need to show precisely how the degradation manifests to declare it unecological.
‘Clean’ coal combustion is similarly dismissible. If coal’s CO2 (greenhouse) by-product could be dumped (‘sequestered’) without ecological consequences, the entropy law would be violated thereby making the whole science of thermodynamics incomprehensible.
Isn’t nature’s geothermal energy, if unused, simply wasted? This question is superficial because it deals only with energy. The relevant question is: Does geothermal have entropy negation (a solar component)? If not, it is unecological. From an entropy perspective, we don’t need to employ a team of engineers to investigate whether geothermal’s accelerated cooling of magma releases ‘too much’ CO2 to sequester. CO2 waste dumps aren’t ecological. If an energy project is purely earth-derived (no solar negation), it provides no ecological solution.
Of course, minor solar entropy compensations soon wash out among infrastructure, transportation, and other supporting technologies. This means our solar applications must be relatively direct (wind, solar panels/concentrators, possibly hydro, etc.).
Some may still cling to the idea of ‘affordable decline’. But keep in mind, most entropy effects ultimately manifest as waste heat. Here, we are up against our ecological limits. Global warming makes this abundantly clear. We can no longer settle for lesser evils.
Summing up, our only practical means of negating technology’s inevitable entropy (eco-degradation) is solar incorporation. No solar, no sustainability, no ecological solution. Go solar or decline!
What about turing CO2 into UREA, lots of plsants turn CH4 into CO2 then to urea. we can make fertilizers and methanol
Reply | Report Abuse | Link to this@shoshin Recycling the carbon in the air over and over by breathing it is quite a bit different from digging up the massive amounts of carbon locked underground in fossil fuels and blasting it into the atmosphere.
Reply | Report Abuse | Link to thisWe're also made of water, but you throw us under it and we drown, so you may not want to repeat that argument.