About the SA Blog Network

Guest Blog

Guest Blog

Commentary invited by editors of Scientific American
Guest Blog HomeAboutContact

Can we capture all of the world’s carbon emissions?

The views expressed are those of the author and are not necessarily those of Scientific American.

Email   PrintPrint

In 2011, the world will emit more than 35 billion tons of carbon dioxide. Every day of the year, almost a hundred million tons will be released into the atmosphere. Every second more than a thousand tons – two million pounds – of carbon dioxide is emitted from power plants, cars, trucks, ships, planes, factories, and farms around the world. The average citizen of the world will account for the release of four and a half tons – 9,000 pounds – of CO2 this year. The average American will be responsible for four times as much, almost 18 tons, or 36,000 pounds of carbon dioxide this year, roughly a hundred pounds of carbon dioxide emissions for every day of the year.

While humans emit far less carbon dioxide than nature, the amount we emit exceeds the capacity of plants and oceans to absorb on top of the amount they’re already absorbing from natural sources. As a result, most of the carbon dioxide we emit remains in the atmosphere. Year over year, the atmospheric concentration of CO2 creeps up. It will rise only half a percent in 2011, a seemingly tiny change. Yet tiny changes add up. Over the 50 years since 1960, the amount of carbon dioxide in the atmosphere has risen nearly 25%. Since the start of the industrial revolution it has risen by 45%, putting it at a level not seen in millions of years.

On current course and speed, by 2050 atmospheric CO2 levels will rise by another third from their already record high levels, making CO2 twice as plentiful in the atmosphere than at any point during the lifetime of our species.

Without reversal or mitigation, the continued pumping of CO2 into our atmosphere will eventually warm the planet to the extent that catastrophic changes ensue. The only serious debate at this point is just how quickly those catastrophic changes will occur, and which regions will see them in what forms.

To avoid those changes, we need to keep the level of CO2 and other greenhouse gasses in our atmosphere at a manageable level. It’s unlikely this can be above 450 parts per million in the atmosphere. To stabilize at those levels, carbon dioxide emissions in 2050 will need to be less than half of what they are today, and less than one quarter of the levels they’re on track for if we continue with business as usual. Compare the bottom blue line in the graphic below, which depicts the necessary levels of carbon dioxide in the atmosphere and carbon emissions to achieve them, with the top red line, which depicts something close to business as usual. (Note that in the bottom graph, emissions are listed in billions of tons of carbon rather than billions of tons of CO2. Multiply tons of carbon by 3.67 to get tons of CO2.)

We hear a lot today about ways to achieve lower emissions and thus lower CO2 concentrations in the atmosphere – more efficient cars, green energy sources like solar and wind, changes in lifestyle, and so on. Another option is to take specific steps to remove carbon dioxide from the atmosphere, either by removing it from the exhaust of power plants and other sources, or by scrubbing it out of the atmosphere later. Is it possible to capture enough CO2 in this way to make a difference? What would it take? Should we even pursue this path, or is it a distraction from cutting carbon dioxide emissions other ways?

Why Capturing Carbon is a Good Idea

The best way to keep carbon dioxide levels from rising in the atmosphere would be to simply never emit carbon dioxide in the first place. An ounce of prevention is indeed more valuable than an ounce of cure. Unfortunately to completely eliminate carbon emissions we would need to go to 100% non-CO2 emitting sources of electrical power – solar, wind, hydro, and nuclear -, and simultaneously convert all transportation to either electric vehicles (powered by zero-carbon electrical sources) or entirely fueled by next generation biofuels. To understand that, let’s look at the two most plentiful sources of carbon emissions: electricity generation and transportation.

Electrical generation is the number one source of carbon emissions, making up roughly 40% of carbon dioxide emissions on the planet, most of that from the burning of coal. Most electricity on the planet is used to heat and cool buildings. Green building standards could cut electrical bills, but the lifetimes of buildings are long, and getting owners to retrofit is difficult. The other way to address carbon emissions from this sector is to switch to low-carbon ways of generating electrical power.

As I’ve posted about previously, the cost of solar power is dropping exponentially, and will cross below the price of coal-fueled electricity by 2020. Unfortunately, solar suffers from intermittent supply. At night and on cloudy days, the available electricity drops. Solar power plant manufacturers are working on solar power storage systems to offset this problem, but today the leading edge is to provide 6 hours of storage, enough to make it through the evening television hours, but not enough to provide power 24/7 or to make up for cloudy days or weeks. Energy storage also adds to the cost of electricity, since the storage systems have to be built and paid for. Wind power, far less abundant than solar and far more stagnant in price, suffers similar and even larger problems of intermittent supply. The result is that, until and unless we have breakthroughs in power storage, solar and wind will top out at between a third and a half of the planet’s electrical power needs.

Transportation is the second largest source of greenhouse gas emissions on the planet, accounting for around a third of all greenhouse gasses humans produce. Transportation can be made greener by increasing fuel efficiency of vehicles through technologies like hybrid drive systems, regenerative braking, and lighter and more aerodynamic chassis. Yet these changes affect mostly in-city passenger driving. They have far less effect on cross country transportation on trucks (where cargo makes up more of the weight and traffic patterns are less stop-and-go) and almost no impact on air travel. New aircraft design concepts could cut air travel fuel usage by half, but it will take decades to turn those concepts into production aircraft, and more decades to replace the aircraft already in use.

Electric vehicles charged with electricity from low-carbon sources would do better, but electrical vehicles suffer from the very low power densities of batteries when compared to hydrocarbon fuels (as much as a factor of ten lower) and resulting in heavy vehicles with short ranges. In addition, until night time power is low carbon, charging an electrical vehicle at night, in most places, will essentially be an exercise in burning coal. And while electric motors are more efficient than internal combustion engines, electric cars charged by coal-fueled power plants will still result in net carbon emissions.

The one major hope for transportation to become green is the development of next generation biofuels. Biofuels help with carbon emissions because growing the feed-crops for them extracts carbon dioxide from the atmosphere. While that carbon dioxide is released again when the fuel is burnt, it’s an almost net-zero cycle, unlike the burning of fossil fuels that have been in the ground for tens of millions of years.

Unfortunately, current biofuels crops including corn, switchgrass, and oil-seed rape produce less than half a watt of energy per square meter and compete with food crops. They are both too low in power density and too adverse for world food prices to be practical as large-scale replacements for petroleum products. We can effectively rule those out from having a large effect. Next generation biofuels, including genetically modified algae that can grow on salt water (and thus not compete with food crops) and capture as much as 5 watts per square meter are more promising. However, they have yet to be proven.

If we assume that automotive fleets go up in efficiency, that aircraft go up in efficiency somewhat, and that some biofuels come online, we can perhaps look forward to a reduction in transport emissions of about half over the next thirty or forty years, about the same as we see for electrical generation. That, combined with an increase in solar and wind, leaves about half of the world’s carbon emissions in 2050 still being emitted. It would effectively keep emissions steady with today. That’s insufficient. It would leaves us still walking down the path to catastrophe at today’s rate. Something more is needed.

In that context, it makes sense to talk about capturing carbon dioxide, above and beyond the proposals to reduce its emissions above, and storing it someplace safely out of the atmosphere.

How Do We Capture and Store Carbon Dioxide?

Broadly speaking, there are two types of carbon capture systems, though there are many possible ways to build systems of each type. The first sort of system is focused on capturing carbon dioxide from power plants where fuel is being turned into electricity. This is commonly referred to as Carbon Capture and Storage or CCS. In principle it could reduce the carbon emissions of coal-powered electrical plants by 90%. It cannot, however, offset the carbon emissions from transportation or other smaller sources such as farming and deforestation.

To tackle those emissions, another form of carbon capture called Carbon Dioxide Air Capture or Carbon Dioxide Removal (CDR) has been proposed. CDR devices could exist anywhere, not just near power plants, and capture carbon dioxide from the very dilute concentrations it exists in atmospherically.

Both forms of carbon capture rely on storage of the carbon dioxide. To store carbon dioxide, it must first be compressed into a liquid, then piped or shipped to an appropriate location, and finally injected into suitable geological formations kilometers below the surface of the earth. There the CO2 will remain for at least thousands of years, if not far longer.

Both forms of carbon capture require energy as well. Carbon capture at coal-powered electrical plants has the advantage of having the carbon dioxide available at extremely high densities and potentially being able to take advantage of waste heat from the plant. Even so, energy is required. At minimum, 70 kilowatt hours of energy is required to compress a ton of CO2 from a gas into a liquid. Additional energy is then required to pipe it to a suitable storage location, and then to pump it into a reservoir kilometers below the surface of the earth.

Capturing carbon dioxide away from power plants, from normal atmospheric air, requires even more energy. The basic physics tells us that at minimum an extra 130 kilowatt hours of energy is required to capture carbon dioxide from normal atmosphere, even before spending the energy to compress it into a liquid or pump it into the ground.

We might think that the fact that additional energy is required to capture carbon dioxide means that it’s a losing proposition. After all, that energy itself will result in more carbon emissions. Fortunately, even if we use the dirtiest fossil fuel – coal – the additional energy required emits far less new carbon dioxide than we capture. At theoretical best efficiency, capturing CO2 from coal power plants would emit less than one ton of new CO2 per ten tons captured. Capturing CO2 from thin air – and using coal to power the process – would emit a best case of two tons of CO2 for every ten tons captured. Seen another way, the best possible net capture efficiencies when the process is powered by coal are 91% and 83%, respectively.

Powering carbon capture devices by sources other than coal would be far better. CDR – capturing CO2 from normal atmospheric air – could be powered by hydro-electric, wind, or solar power, at locations and times when that power is the cheapest and most plentiful.

Capturing carbon requires more than just energy, of course. It requires investment in the physical infrastructure to capture the carbon, to compress it, to transport it to the right site, and to pump it incredibly deeply into the ground. It requires manpower to do these things, and to maintain monitoring of the sites to ensure that sequestration has been done properly and that unexpected leaks don’t arise.

All together, the pieces of carbon sequestration add up to a noticeable cost. How much cost? A recent study at Harvard’s Kennedy School of Management reviewed all previous work on cost estimation of CCS at coal power plants, and determined that the long term cost would be somewhere between $35 and $70 dollars per ton of carbon dioxide captured and stored. The costs would start much higher for the first plants, as high as $150 per ton of CO2 captured and stored, but would drop rapidly as more plants were built and the industry scaled.

Fewer cost estimates are available for carbon capture from general atmosphere, but a number of private companies are now at work in the field, and the estimates they’ve discussed fall in roughly the same range – $100 per ton of CO2 in the early stages, dropping to perhaps $30 to $50 per ton of CO2 as the technology is scaled.

If we could achieve a cost of $50 per ton of CO2, what would that do to energy prices? Every $10 per ton of CO2 increases the cost of electricity by 1 cent per kilowatt hour, and increases the cost of gasoline by 10 cents per gallon. So a $50 per ton cost to capture CO2 would, if applied back to the cost of CO2 emissions, raise electricity prices by 5 cents per kilowatt hour and raise gasoline prices by 50 cents per gallon. That is not a bad price for avoiding catastrophic changes to the planet.

Scale of the Challenges

Yet carbon capture technology is not without its problems. There are concerns that injecting high quantities of liquid CO2 near fault lines that are under tension could trigger earthquakes years ahead of when they would normally occur. At least one recent study has also shown that there is a risk of sequestered carbon contaminating drinking water.

The biggest technical challenge is sheer scale. Carbon dioxide compresses to a liquid about half as dense as water. A barrel of liquid CO2 weighs 70 kilograms or 160 lbs. To capture all 35 billion tons of CO2 the world will emit in 2011, we would produce nearly 470 billion barrels of liquid carbon dioxide, or roughly 67 barrels per person alive on Earth. That quantity is more than 17 times the total number of barrels of oil the petroleum industry pumps out of the ground each year.

Fortunately, while the volume is vast, geological structures exist to store this much. The Intergovernmental Panel on Climate Change estimates that geological structures away from fault lines and drinking water could store at least 1.1 trillion tons of CO2, and possibly as much as ten times that. A report by the Global Energy Technology Strategy Platform group at Batelle found geological capacity to store roughly a staggering 10 trillion tons of CO2 safely.

At the high end, that would provide storage to sequester more than 200 years worth of CO2 emissions. Even if we limit our estimates to existing oil and natural gas fields alone, structures whose capacities we’re more certain of, we could store around 900 billion tons of CO2, or enough to keep atmospheric carbon concentrations below 450ppm for the rest of this century. These fields have long term stability demonstrated by the fact that they have held oil and natural gas deposits for millions of years. The carbon they’d sop up would give us significant time to keep working on improvements to zero-carbon power and transport technologies without exacerbating climate change.

The challenge is less in the storage capacity and more in the pumping and transportation capacity. To make a significant dent with carbon capture, we would need to create a pumping and piping infrastructure with a capacity more than ten times that of the current oil industry. That is a major undertaking. It’s well within our capabilities, but not without substantial cost. At the same time, there may be no route to a climatically stable world that avoids this.

How to Make it Happen

A number of carbon capture and storage pilot programs are underway today, but the technology is very much still in an experimental phase. If concerns about drinking water and seismic activity can be addressed – which the IPCC and EPA both believe – How do we turn carbon capture from a science project into a reality?

My firm belief is that the best way to turn any dirty industry into a clean industry is to make it profitable for companies in the industry to do so. Or, to put it another way, the way to encourage change is to make it too costly to remain dirty for any company to want to do so.

This is not meant in any way to be punitive. The coal and oil industries have reached the scale they have and the emissions they have because consumers have demanded more and more energy, and because the industries have not been told to eliminate their carbon dioxide output. It makes no sense to blame industry when consumers and legislators have worked together to create a landscape in which their current actions are the most sensible ones. To change the actions of energy companies, we need to change the landscape.

The best way to go about doing this is to place a price on carbon. Pumping carbon dioxide into the atmosphere, where it causes long term damage to a planet shared by all, should be something one needs to pay for. The price paid should be at least commensurate to the cost of undoing any harm. On the flip side, efforts that remove a pollutant from the atmosphere should be rewarded at the same rate.

We’ve seen estimates of cost of mature carbon capture systems that range from $35 – $70 / ton, and of the very first systems at around $150 / ton. Where should we set the price?

I would propose a price that starts at zero but ratchets up progressively to $100 / ton (in today’s dollars), at an automatic increment of $5 / ton each year. $100 / ton gives buffer room over the current price estimates for carbon capture and storage. This allows for some flexibility if cost estimates turn out to be too low. On the other hand, if those estimates are accurate, or if the cost of sequestering a ton of carbon turns out to be anywhere under the $100 / ton carbon price we would set, then it would be cheaper for power plants to adopt carbon capture technologies than to pay the carbon price. In the worst case, if the full carbon price is paid, the cost of coal electricity, 20 years from now, would be 10 cents higher per kilowatt hour. If capture costs end up at $50 / ton (the midpoint of estimates), then the cost of coal electricity, 20 years from now, would be 5 cents higher per kilowatt hour.

The gradual and predictable increase in the carbon price would soften the immediate economic shock of it, while giving both consumers and corporations clarity about the future and the ability to plan logically for it. A price even 20 years in the future would push utilities to start planning now for how to retrofit existing power plants and build new ones in ways that minimize carbon emissions.

Paradoxically, a carbon price would also slow the rise of oil and other fossil fuel prices, by encouraging conservation now and thus reducing demand.

A carbon price of this size would have other beneficial effects outside of carbon capture. It would make solar, wind, and nuclear power more attractive on a price basis. Over 20 years it would raise the price of gasoline by $1 / gallon, less than the difference in prices between the US and Europe, but enough to make electric cars, hybrids, and new, more fuel-efficient aircraft designs all more attractive as well.

Perhaps most importantly, a carbon price would create a gold rush of carbon harvesters working to pull carbon dioxide out of the atmosphere. Whoever could get their cost of capturing and sequestering carbon dioxide down the lowest would reap the largest profits per ton of carbon captured, driving innovation in ways to capture carbon at ever cheaper prices. A carbon price would align incentives, making it in the best interests of corporations and entrepreneurs to lower the amount of carbon in the atmosphere. That’s something we should all be excited about.

In Summary

Carbon capture and storage technology isn’t a solution to our climate problems on its own. There are unknowns and challenges of scale that need to be addressed. Possible locations for carbon sequestration aren’t infinite in size. They will eventually fill up. But carbon capture can be done, and can be done at massive scale, and at a price that would not destroy our economy. Doing so would give us more time to find ways to switch to inherently zero-carbon methods of powering our civilization and fueling our vehicles. As a complement to efficiency, green energy, and other ways to reduce our carbon emissions, capturing and storing carbon dioxide from our power plans and our atmosphere would be an extremely powerful tool. The best way to encourage carbon capture and storage turns out to be the best way to encourage efficiency, green energy, and other approaches to reducing the carbon in our atmosphere: put a price on carbon emissions.

Sources and further reading

IPCC, "IPCC Special Report on Carbon Dioxide Capture and Storage," prepared by Working Group III of the Intergovernmental Panel on Climate Change [Metz, B., O. Davidson, H. C. de Coninck, M. Loos, and L. A. Meyer (eds.)]. Cambridge University Press, Cambridge, U.K. and New York, 442 pp., 2010.

International Energy Agency, "Carbon Capture and Storage: Progress and Next Steps," 2010.

Global CCS Institute, "The global status of CCS: 2010", Canberra.

Al-Juaied, Mohammed A and Whitmore, Adam, "Realistic Costs of Carbon Capture" Discussion Paper 2009-08, Cambridge, Mass.: Belfer Center for Science and International Affairs, July 2009.

JJ Dooley, RT Dahowski, CL Davidson, MA Wise, N Gupta, SH Kim, EL Malone, "Carbon Dioxide Capture and Geologic Storage", Batelle Global Energy Technology Strategy Program, April 2006.

"Capturing Carbon Dioxide From Air", US National Energy Technology Laboratory, Klaus S. Lackner, Patrick Grimes, Hans-J. Ziock,

About the Author: Ramez Naam is a computer scientist and entrepreneur. He is the author of More Than Human (Broadway Books, 2005), which the Los Angeles Times called "a terrific survey of current work and future possibilities in gene therapy, neurotechnology, and other fields." For More Than Human, Naam was awarded the 2005 H.G. Wells Award for Contributions to Transhumanism. Naam is a Fellow of the Institute for Ethics and Emerging Technologies and blogs at Unbridled Speculation. He lives in Seattle, where he is currently working on his next book, The Infinite Resource: Human Innovation and Overcoming the Challenges of a Finite Planet. You can see Naam speak at a special event at the World Future Society 2011 conference in Vancouver, British Columbia.

The views expressed are those of the author and are not necessarily those of Scientific American.

Comments 30 Comments

Add Comment
  1. 1. JamesDavis 10:19 am 03/31/2011

    Carbon capture is a prolonger of misery, death and destruction. For every coal burning, oil burning and natural gas burning power plant, build a Geothermal power plant -1.5% environmental footprint and install hydro and hydrokenitic turbines at our dams, rivers and wave turbines at our ocean coasts, 0% carbon footprint, and then shut down fossil fuel burning power plants and you will not have to worry about carbon capture or poisonous seepage or mind alternating high costs a couple of decades down the road.

    Start mass producing electric vehicles, we can sacrifice for a decade until new battery technology comes out, that can be charged by solar or by the clean energy coming from non-carbon power plants. This can be done in less than a decade, not 40 or 50 years from now.

    For three years during WWII, there was no autos manufactured in America. We directed our attention to making war machines on a massive scale and we did it. We can sacrifice with the number of new and used automobiles we have now, for five years, until we can quickly convert over to and start mass producing electrical vehicles, storage batteries (liquid salt, liquid metal and molten salt) and clean energy producing power plants, geothermal, wave energy and solar. If we do not make this sacrifice now, we may not be around to worry about storing carbon.

    Link to this
  2. 2. lamorpa 1:24 pm 03/31/2011

    "For every coal burning, oil burning and natural gas burning power plant, build a Geothermal power plant"
    1) What do you do compensate for the 85% reduction in power output of the largest geothermal plant even proposed today, compared to the average fossil fuel burning plant?
    2) Multiplied by the < 5% site suitability for geothermal plants, leaves you with a minuscule
    fraction of the generated power by this plan. Sure it will reduce emissions, but what about the 99% loss in available power?

    "install hydro and hydrokenitic turbines at our dams, rivers and wave turbines at our ocean coasts, 0% carbon footprint"
    Except for the construction and maintenance of said plants and the increase in infrastructure required for same, and ignoring the related negative environmental impact. All significant sources of river power have already been tapped. Wave turbines only exits on the cover of Popular Science, and have never been found to be practical and net positive in energy when construction, maintenance and lifespan are included.

    "Start mass producing electric vehicles [and magically find a way to do it without the required massive investment in natural resources, production facilities, maintenance, etc.], we can sacrifice for a decade until new battery technology comes out [since with current technology, there is no net energy gain for electric vehicles, they're actually net carbon worse currently], that can be charged by solar [if you only plan to drive 8 minutes a day] or by the clean energy coming from non-carbon power plants [which won't exist during this time]."

    Link to this
  3. 3. KattM 1:32 pm 03/31/2011

    What would it take to split the CO2 into its component Carbon and O2 parts and sell those to industry? Would not using nuclear power allow us to do this? (I have fancies of seeing plate diamond windows become common, but that’s just me.)
    That might avoid the dangers of pumping the liquid gas into deposits and then having to make sure they don’t leak or are drilled into in the future.

    Link to this
  4. 4. lamorpa 1:58 pm 03/31/2011

    So you propose using atomic power to crack the CO2 bonds created by burning fossil fuels? Why not just use the atomic power in the first place. Is this a serious question?

    Link to this
  5. 5. ZebulonJoe 4:16 pm 03/31/2011

    Tripe, tripe and more tripe. The temperature of the earth was only three degrees higher when CO2 was at about 8000 ppm.

    All that happens is that plants grow better.
    Again, read "Textbook of Gravity Sunspots and Climate" by Frederick Bailey.

    Our climate is in a very long cycle (about a thousand years) and UK temperatures were about the same 1000 and 2000 years ago.

    And the present climate expectation is an ICE AGE within 20 years. It has not warmed at all since 1998.

    I add (again) that the originator of the computer model now used for climate change is now a climate sceptic.

    Link to this
  6. 6. KattM 5:14 pm 03/31/2011

    Based upon the problem as presented by Mr Naam, which is to find a way to negate the effects CO2 is having upon climate. The issue my question addresses is what to do with the CO2 once removed from the atmosphere.
    I see such a solution as a way to possibly recoup money from the harvest. If nuclear power or geothermal (as proposed by Iamorpa) were implemented on a scale to more than meet humanity’s need, then this would seem to me to be a possible application of any excess power, for the removal of CO2 from the atmosphere stands alone as its own goal.
    If we continue to develop nano-carbon technologies, then I see the pure carbon produced as being a feedstock for the products produced using such technology.
    If there were also a steady source of Hydrogen, then the O2 might also be used to product water and power on its own. I’m sure O2 has plenty of current industrial/medical applications as well.

    Link to this
  7. 7. Eclipse 5:30 pm 03/31/2011

    Global warming is a serious problem, and I don’t doubt the physics of Co2 spectrometry. But I understand the IPCC reports have ‘worst case’ business as usual scenarios *increasing* oil and gas and coal consumption out to 2100?

    This is impossible. Even the USA Joint Forces Command admits we are at peak oil now, and could see dramatically reduced oil production by 2015. Peak gas is not far behind that, and according to the University of Newcastle Australia, peak coal is anywhere from now to 2048. NOTE: Peak does NOT mean running out, it means burning the best half, the low-hanging fruit, and that the 2nd half of any resource is more expensive to mine.

    Peak coal will raise the costs of coal production to the point where SAFE Gen3 nukes are competitive, and we’ll see the market switch. And when Gen4 reactors arrive off the production line, we’ll burn the waste from Gen3 reactors and have enough ‘nuclear waste’ (depleted uranium) to run the world for 1000 years.

    What energy crisis?

    And if we start building skyscrapers out of the new wood (with the same tensile strength of reinforced concrete but half has heavy) we’ll lock thousands of tons of carbon away in our buildings!

    We CAN fix this!

    Link to this
  8. 8. scientific earthling 6:55 pm 03/31/2011

    Dream on dreamers, Carbon capture and storage uses all the energy generated by creating carbon dioxide. Have any one of you heard of the law of conservation of energy, I know its old, energy and mass are related, but if we have no mass/energy conversions, it is still valid.

    You get energy by releasing energy stored in carbon based compounds. These compounds were created by absorbing solar energy and converting CO2 to sugars and then other carbon compounds over extended periods of time. Now you don’t want the CO2 in your atmosphere, your solution: 1. Reveres the process by creating new carbon compounds. 2. Liquifying CO2 and pumping it into the bacteria sustaining plastic mantle of our planet? Ever heard of plate-tectonics?

    Do your sums, it is not worth burning carbon compound for energy without leaving the CO2 in the atmosphere.

    Link to this
  9. 9. RamezNaam 7:53 pm 03/31/2011

    Scientific Earthling: That’s actually not correct. We get the energy out of hydrocarbons by making a chemical change to them, reacting them with oxygen, which produces CO2 as a byproduct. Converting CO2 back into a hydrocarbon would use as much energy as was gained by burning it, and would thus face the problems you speak of. But simply compressing it into a liquid uses far less energy than was gained by burning the hydrocarbon to get it. How much less? Capturing, compressing, shipping, and pumping CO2 would use roughly 10-20% of the energy gained in burning it. The physics of this are well understood.

    Link to this
  10. 10. RamezNaam 7:54 pm 03/31/2011


    Undoubtedly there will be some market for the gained CO2. However, it’s unlikely to approach anywhere near the volumes of CO2 we must remove from the atmosphere in order to make a dent. So via this path, we would end up with a large volume of liquid CO2 which needs storage. Fortunately, storage is relatively cheap, making up perhaps 10% of the overall cost.

    Link to this
  11. 11. RamezNaam 7:58 pm 03/31/2011


    I agree with you we can fix this.

    Unfortunately, one side effect of peak oil would be to push consumption towards dirtier petroleum sources or dirtier fuels that emit more CO2. For instance, retrieving oil from tar sands, as of today, requires significantly more energy than drilling for oil, and produces a lower grade of oil which requires more energy-intensive refining.

    Similarly, if we truly found that oil supplies were below demand, we might see companies turning to coal liquefaction to produce a liquid fuel that could be dropped in to existing vehicles. That would address energy needs, but would release around twice as much CO2 as burning current gasoline.

    The best hope is that rising fossil fuel prices spur more investment in biofuels, fuel efficiency, solar, and other greener methods. I do think that will happen. In the meantime, though, we’d be foolish to not embrace every method we can to keep CO2 in the atmosphere at manageable levels.

    Link to this
  12. 12. sethdayal 7:58 pm 03/31/2011

    You saw it here first – global warming ended by the never before discussed anywhere in the blogosphere technique, I modestly call it Sethquestering.

    The author’s approach requires numerous leaps of faith and has been totally debunked here.

    No power company on earth would take the liability risk of transporting large amount of CO2 by pipeline when a single leak could kill a million people. What happens when one of those secure storage vaults springs a leak during an earthquake or accident and another million folks are smothered. Nope – this is foolishness.

    Fortunately there is a way using dirt cheap clean and green nuclear power, now approaching $1B/GW with factory production ramping up in China.

    It would take about 70 nukes running 24/7 built in Greenland, Ellesmere Island or Antarctica to turn 1 PPM of atmospheric CO2 into 1 cu mile of dry ice. A coupla of canyons filled with dry ice should do’er. To take us down 40 ppm to the recommended 350 ppm over the ten years we’d need to build the 10000 nukes costing $10000B replacing fossil fuels world wide, would take roughly 300 nukes temporarily tasked. When the job was done the dry ice would be layered over with ice, one or two of the nukes would be used to keep it all frozen, and the rest assuming the units are MSR’s transported south on barges.

    Hopefully, those future nuke builds will use GenIV reactors requiring our corrupt politicians all on Big Oil’s payroll, to end their thieving treasonous ways.

    Faint hope, I know but perhaps somebody in the US (hello Dr. Chu are you listening?) will now get behind the US invented nuke waste burning Molten Salt Reactor. We can spent $100B’s on weapons R&D but we have nothing for something as fundamental as the nation’s power and the Sethquestered end of the global warming.

    David LeBlanc at the U of Ottawa has redesigned the Molten salt reactor as a nuke waste burning DMSR which would resolve all safety and cost issues with nuclear. This tech was actually built and ran in a reactor for many years – even flown around on an airplane. By using existing nuclear waste for fuel it could power the world for hundreds of years.

    All it needs is $5B, 5 years, and a place to build em , and factory produced units would be streaming out fast enough to eliminate fossil fuels 5 years later.

    Nuke waste could be remanufactured into DMSR fuel right at existing nuke sites.

    Call your politicians and ask them if all that Big Oil graft is enough pay to sell out their country.

    Link to this
  13. 13. sethdayal 8:31 pm 03/31/2011

    No such thing as clean coal with thousands of cubic miles of deadly toxic forever ash deposits, and deadly CO2 stores waiting to smother entire cities.

    Large scale geothermal involves drilling real deep into the earth, injecting water and pumping up the superheated steam polluted with sulfur. Unfortunately, nobody has developed a pump that works at 450 degrees C, the water injection cracks the hot rocks causing lots of small and very scary earthquakes, and turbines that can handle a regular dose of sulfuric acid.

    Your car will be powered by a Mr. Fusion unit first.

    Wind and solar power costs are actually now rising slowing as recent fire sales due to the end of insane Euro feedin tariffs disappear. 80% of the cost of solar, comes from structural, electrical and installation rather than the cells.

    The wind/solar/OCGT gas backed projects today never have any transmission or gas backup costs included which add $16B/Gw to the price. Almost 100% of the energy produced comes from gas.

    The $140B/Gw required to eliminate the gas and go green with green storage is simply impossible economically.

    Here’s PGE’s latest wind farm build at manzana $15B/GW 10 cents a KWhr double that at PGE’s discount rate)

    WIND: 10,20,115 cents a kwh (str8,trans+gas,green)

    How about Duke Solar PV in NCarolina recently $43B/GW ,25 cents a kw or 50 cents a KWh at Dukes discount rate

    SOLAR: 25,35,130 cents a kwh (str8,trans+gas,green)

    A 100% green household would spend $1000 a year on nuke power, and $58K on wind power.

    Enhanced Candu built Qinshan China 1.6Gw $2.9B or 1.2 cents a kwh + fuel .5 cents a kwh. Recent quotes for AECL first of a kind ACR-1000 units at Peace River and Darlington confirm these numbers.

    NUCLEAR: 1.7 cents a kwh.

    Coal is 6 cents and gas 4 cents a kwh.

    You could add another .5 cents a kwh for O&M and Decomm costs to all.

    A fossil to nuke conversion would overnight end unemployment, end the global warming/peak oil menace, save the lives of thousands of Canadians every year from coal/gas air pollution and create the greatest construction boom in history.

    As we convert to nukes, NG electricity and heating applications would immediately convert to nuclear electricity. The freed up gas would be available to make CNG, methanol, DME (propane), and synfuel transportation fuels as we transition to nuclear produced synfuels and electric vehicles.

    Check out Shell’s Pearl experience with its $20 a barrel first of kind natural gas to liquids plant in Qatar. A plant built here could make diesel out of natural gas at $15 a barrel.

    Link to this
  14. 14. RamezNaam 8:50 pm 03/31/2011


    Carbon capture does have its risks. I agree with you fully on that. Yet the Intergovernmental Panel on Climate Change, the International Energy Agency, the US Department of Energy, and the Environmental Protection Agency (to name a few) believe it is feasible.

    The geological structures sequestered carbon would be stored in, kilometers below the surface of the earth, have in many case held oil and natural gas deposits at far higher concentrations for millions of years.

    Undoubtedly, as with any new technology, there will be accidents and mishaps, which we’ll learn from over time. Those are not a reason to dismiss the approach completely.

    As for nuclear, I fully support a much expanded role for nuclear power (with enhanced safety based on the past decades of learning) in powering our economy. If that happens, the combination of nuclear and solar could eliminate coal burning entirely.

    Eliminating emissions from transportation, manufacturing, agriculture, and other sources is more difficult. If our aim is to get to net zero carbon emissions, it will be difficult to do so in the next few decades without carbon capture and sequestration.

    Link to this
  15. 15. scientific earthling 11:17 pm 03/31/2011

    Ramez Naam: You should read what I wrote carefully. The best solution is to reconvert to organic or inorganic carbon compounds. This process will take more energy than was generated by burning carbon. There are losses each time, amongst them, you do not recover the latent heat of water expelled as steam.

    When it comes to compressing and pumping into voids, well how long do you think it will remain captured in a plastic mantle, subject to tectonic plate movement?

    By the way the coal seam gas industry has been incarcerated by conventional gas and oil mining industries for using fracturing techniques in the coal seam to increase permeability and increase the flow rate of methane. This of course is the pot calling the kettle black. From a business point of view, its brilliant strategy trying to keep gas recovery a task only multi-billion dollar companies can indulge in.

    At the end of the day, the cause of the problem is not CO2, it is out of control human population growth.

    Link to this
  16. 16. b2252 3:08 am 04/1/2011

    Has anyone worked out the economics of splitting the salty and "water-of-no-economic-value" to produce new Oxgen & new hydrogen (using only the concentrated-solor- thermal- power technology) to bring-down the co2 ppm levels from the projected 450 to acceptable levels?

    Link to this
  17. 17. DennisP 9:43 am 04/1/2011

    To make it happen, allow anyone who absorbs CO2 to sell emission rights for equivalent amounts. Major emitters either pay a fee or submit purchased emission rights.

    To ramp up gradually, just start with a low fee and gradually increase it. Preferably, distribute the fees to citizens on an equal per-capita basis.

    I used this idea as the basis for my climatecolab submission, which resulted in MIT paying my way to present the idea to the U.N. Secretary General’s advisory team on climate change.

    Link to this
  18. 18. KattM 12:36 pm 04/1/2011

    Yes, I suppose it would take a massive shift in current industrial materials usage for the kind of demand I picture.
    Thank you for your response.

    Link to this
  19. 19. KattM 12:42 pm 04/1/2011

    Perhaps all that carbon & oxygen might be useful for future space exploration.. carbon nano-technology requiring massive amounts of carbon to build a space elevator? Or a transport ship, though that would also need nitrogen and the other trace gasses.
    Dreaming again, but that’s me.

    Link to this
  20. 20. KattM 1:01 pm 04/1/2011

    Warm air is able to carry more moisture than cold air. Hence, more snow falls during warmer winters than colder ones.

    Link to this
  21. 21. KattM 1:09 pm 04/1/2011

    Liquid Salt Reactors are not without some danger. If it is the same as a Thorium reactor (Kirk Sorensen’s blog "Energy From Thorium", 2006), then there are still some risks: the molten salt used in thorium reactors is very corrosive.
    I do support the use of this technology, however, especially as it becomes safer and safer.

    Link to this
  22. 22. RamezNaam 5:10 pm 04/1/2011

    DennisP: I like your proposal. That is another way to get a valid carbon price based on the cost of capture.

    The biggest challenge is that absorbers will be far fewer than emitters initially. The economic shock of that would be quite large. A way to phase that in over time (combining it with a ceiling on non-offset emissions that gradually drops, for instance) would soften the economic blow.

    Link to this
  23. 23. RamezNaam 5:13 pm 04/1/2011

    Scientific Earthling:

    Multiple assessments have found that these geological features should be able to store compressed CO2 for hundreds of thousands or millions of years. Escape in the first century is estimated to be < 1% of the sequestered amount. For comparison, think of oil and natural gas fields. They contain high pressure hydrocarbons formed over hundreds of millions of years, and keep them contained for extremely long timescales.

    Link to this
  24. 24. RamezNaam 5:15 pm 04/1/2011

    B2252: Using solar power (either concentrating solar or solar PV) to produce hydrogen gas from water, which can later be used to create electricity in turbines or in fuel cells, is indeed something that is underway.

    Today, unfortunately, that adds substantial cost to solar installations, but it may eventually be cheap enough to use as a way to generate ‘off peak’ power from solar plants.

    I hope to discuss that in a future post on renewable energy storage, either here or at my blog at

    Link to this
  25. 25. Amused 8:05 pm 04/1/2011

    Global warming we lay people were warned 2 year go would lead to milder winters and warmer summers.The winter of 09/10 was one of thecoldest for some time here inthe UK,but it was well beaten during late winter 2010/11.
    Plants that previously survived have died,these plants range from 2/3 to 10 years or more….so tell me where are our warmer winters.
    I have seen a few winters come and go in my time,now and then a severe one comes along,but not usually two years running.As for warmer summers 1976 was the best summer I ever experienced,with 1984 a close second. From then till today summers have been the same,more like a warm winter.
    I feel the metorilogical office will produce….er facts to claim differently,but tell that to the people like me who live through the weather patterns for decades.
    Back in the 50s our winters were long with lots of snow,we regularly used our sledges,even building igloos on the street,snow fights were a regular occurance.
    The summers we used to walk barefoot to/from the next town 2 miles away,the tar would melt on the roads, we would pick lumps and chew it…true.
    When I think back of households burning coal 6/10 hours a day,hotels,hospitals,factories all doing the same,but burning more all over the world,the cars buses and lorries were less fuel efficent then, 50/60/70/80s summers were on the whole better then,but nothing out the ordinary,except those mentioned.
    You’ll understand why I think our weather patterns are cyclic and think global warming (if real) is one of those cycles,perhaps we should look at the effect of reducing the carbon dioxide to much which might be a bigger catastrophe.

    Link to this
  26. 26. sofistek 4:54 am 04/3/2011

    I wonder why the author thinks that electrically powered cars can be made without fossil fuel emissions. It’s not just the driving of cars that takes energy, the making of them takes energy and much oil.

    He only mentioned planes once. Does he think that planes will be electrically powered?

    Yes, carbon sequestration facilities will fill up eventually, assuming they can be made leak free, so why even bother going down that route, at least not in parallel with powering down our societies?

    Link to this
  27. 27. DennisP 4:49 pm 04/4/2011

    Thanks Ramez! What I’m thinking now is: apply the fee-and-dividend idea advocated by Hansen, where everyone pays a fixed price per emitted ton, and the revenue is distributed to citizens. Price starts low and gradually rises. Since this alone make no provision for absorption, allow people to earn carbon rights by absorbing, and allow emitters to avoid the emission fee by purchasing carbon rights. This gives a predictable and gradual increase. If absorption is too expensive, people just pay the fee instead and we fall back to fee-and-dividend.

    In the proposal I tried to get a gradual increase with a ratio approach, where emitters can offset by purchasing absorption of only a portion of emissions, depending on the overall ratio of emission to absorption. This would make absorption more feasible while the carbon price is low, but then I realized it could backfire if an absorption method uses a lot of CO2-emitting energy.

    Link to this
  28. 28. Eclipse 8:13 am 04/8/2011

    1. Only GenIV nukes that burn nuclear waste can provide all the baseload electricity we need.

    2. However, I’d love to see the economics of MASSIVE SEA-WATER PUMPED HYDRO ‘batteries’. Fresh water hydro dams are damaging to rivers and are mostly used up anyway.

    However, anywhere with a high cliff next to the sea, with some vacant desert next to it, could provide MASSIVE amounts of energy storage that I’m *assuming* would come down in price per unit due to using economies of scale. For instance there is a plan for Australia to use a 7km diameter 20 meter high reinforced earthen wall dam to store enough water to run the whole of the country for 10 hours! Australia only has about 22 million people, but still, that’s a MASSIVE battery!
    See a diagram here.

    But given the challenges we are going to have with peak oil on our doorstep, and the need for electric cars to charge overnight, it seems to me that nuclear power is the only way to go!

    Link to this
  29. 29. bcinnz 12:32 am 11/10/2011

    Even if it were true that man made CO2 produces dangerous runaway global warming, which it is not, man’s contribution is miniscule when compared with nature’s contribution every year. A huge myth is that CO2 levels hardly changed before the industrial revolution, and that it is man’s contribution through the use of fossil fuels that have increased the levels. 90 % of the world’s active volcanoes are under the sea, and no single study has been made to determine their effects on the oceans. Where does all that CO2 and SO2 go? Above sea active volcanoes and termites plus natural wetlands produce the vast majority of CO2 every year, not mankind. Geological records prove CO2 levels have been over 8000ppm and there is no record of any previous dangerous runaway global warming. So why should it be so now? Has the nature of physics changed? Does the CO2 molecule produced by mankind differ from that produced by termites? I suspect a serious driver for this theory is that cash strapped researchers have discovered this approach is highly lucrative. 8000ppm CO2 didn’t cause problems in the geological past, so I don’t accept this theory as valid to explain any warming today. Of course, if warming was caused by natural cycles of the solar radiation and cosmic emissions, then there would be no money to be made on CO2 theories.
    Insofar as temperature measurements are concerned, the only way to measure the real temperature of the earth would be to have millions of sampling points distributed all over the world, all simultaneously recording the temperature every minute and then taking an average of those over time. This is currently impossible, and other efforts, whilst well intentioned, are simply a substitute for valid data, with some self interested researchers using the high point ( even if the data point registered for example less than 1 minute in the 24 hours cycle, as somehow representing a valid sampling data point ) to publish a new record high, and to scare some taxpayer funded government agency to dish out further funds to help prevent dangerous runaway global warming.
    And lastly, whenever scientists tell you the science is settled, then they aren’t real scientists, just possibly arrogant. For years all respectable scientists believed that the speed of light was the maximum speed possible, but that’s also been recently disproved. Fortunately people weren’t taxed to research how we could increase the speed of light….

    Link to this
  30. 30. casperboost 11:06 am 06/25/2012

    Thanks for posting this. I really wish people would pay more attention to articles like this. There is a lot to learn about carbon emissions, but most people don’t know a thing. I think it is a form of careless driving to do so without any regard to the environment.

    Link to this

Add a Comment
You must sign in or register as a member to submit a comment.

More from Scientific American

Email this Article