Carbon Dioxide Capture, Utilization & Sequestration Technical Section

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  • 1.  One aspect of the CCS debate that receives little attention

    Posted 08-14-2023 01:01 AM

    One aspect of the CCS debate that receives little attention is the size of the problem. 7,800 million tons of CO2  emissions adds 1 ppm to the atmosphere, and the IPCC tell us that half of this will be sequestrated by the biosphere and oceans therefore to reduce atmospheric CO2 by 1 ppm, we would need to sequestrate 15,600 million tons, which would double the cost of any project? And in volumetric terms 15,,600 million tons of CO2 is around double the world's entire production of natural gas. It would seem more cost effective to reduce/sequestrate atmospheric CO2 than use CCS technology? 

  • 2.  RE: One aspect of the CCS debate that receives little attention

    Posted 08-15-2023 06:50 AM

    Hi Norman,

    There is a twist when adding up global numbers. Yes, CO2 concentration in the atmosphere increases by 2.5 ppm per year, and at 7.8 billion tons (that's 10^9 tons, or Gt, gigaton) per ppm we need to curb emissions by about 20 Gt per year. Since yearly emissions from energy sources - our destabilizing addition - are 40 Gt, here's half of the cake eaten by the biosphere.

    So emissions must decrease by 20 Gt to get us to a "net zero" condition, where atmospheric CO2 doesn't grow. Of course, the cheapest way to get rid of CO2 is not burning fuel in the first place: energy efficiency, nuclear for base load electricity, you name it.

    How big a role should CCS play? The original Socolow wedge called for 4 Gt of CO2 per year (around 20% of the budget), whereas the IEA Net Zero by 2050 scenario halves that to 1.9 Gt, 10% of the yearly emission budget and 12% of the 15.6 Gt you mention.

    Is that a lot? Global gas production is around 3 Gt, a very similar number. But we need to keep in mind that natural gas is a, well, "gas": away from the critical point its density is around 1,000 smaller than CO2. Thus much bigger volumes, and thus pipes, are needed to handle natural gas than CO2.

    Compressed CO2 is almost as heavy as water, of which we (O&G) inject about 12 Gt per year without flinching. That's six times more than the current CCS goal.

    Doable? You bet.

    Best regards,

    Matteo Loizzo
    Well integrity consultant
    Berlin, Germany