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> We're still a long way from pulling off the sequestration that's actually needed at the scale that's needed. How so? The simple fact that natural gas and oil

> We're still a long way from pulling off the sequestration that's actually needed at the scale that's needed. How so? The simple fact that natural gas and oil still exists, when it comes from 100 million year old biomass, proves beyond a shadow of doubt that geological sequestration holds its integrity at geological timescales. We have also been injecting CO2 at a rate of 1 million tonnes per year at the Sleipner field in the North Sea since 1996, and extensive 3D timelapse seismography shows the CO2 is permanently trapped. Think about that - we have been demonstrating CO2 storage at scale since before the launch of the first Palm Pilot.

yodon 5y ago
The existence of oil shows CO2 can be stored in solid or liquid form, but doesn't show we know how to convert CO2 into that stored form at scale or keep our hands off it once it's stored that way. It's easy to burn oil, it's hard to make it, and it's harder still to not burn it when you know it's readily available.
- semi-extrinsic 5y ago
  CO2 is in the dense supercritical state at the temperature and pressure conditions in storage reservoirs. It's density is between 750 and 850 kg/m3 then (water is 1000). You just have to compress it and pump it down there, and it will stay like that. Honestly, the storage part is a solved problem from the feasibility side. The remaining challenges are mainly cost optimization, across all of capture, transport and storage. And the biggest hurdle is forcing businesses to actually pay for the currently externalized cost of CO2 emissions.
  - yodon 5y ago
    I agree with your thermodynamics, I'm just concerned about finding a volume big enough to store climatically meaningful amounts of CO2 in that form. 40 billion metric tons per year of CO2 in the form you describe is around 30 billion cubic meters, and you need to find that much storage volume every year just to keep things from getting worse. If you want to actually make a dent, like rolling things back to the year 2000 (which likely isn't enough, but is a real impact), that's more like 600 billion metric tons or 450 billion cubic meters. That's roughly equivalent to 400 mountains 5000 feet tall. It's a huge volume of material we're talking about finding a place to store if we're actually trying to make a real dent in climate change.
    - s1artibartfast 5y ago
      For context, Global Natural Gas production is approximately 4,000 billion cubic meters per year. To sequester the world's carbon emissions, we would need to move and store <1% the volume per year.
      - Robin_Message 5y ago
        That's apples to oranges: we don't store anything like a year's worth of gas. And anyone in Europe can tell you that natural gas transfer and storage is far from a solved problem.
        s1artibartfast 5y ago
        The idea is not to actively store it, but dump it somewhere where it will store itself. Europe is a great example of how we have the technology to transfer huge amounts of gas, and the challenges are largely politics and capital. Nordstream #1 moves 60 billion m3 of gas 1,200 km and cost ~$10 billion
    - markcyffka 5y ago
      We also got calculations that yielded literal mountains ranges of carbonate... That's not to say carbonate cannot be part of the solution, but maybe it is unlikely to be the only solution.
    - idiotsecant 5y ago
      If you asked a pre-industrial person how in the world it would be possible to source, refine, and distribute enough crude oil to power the modern world they would quote some similarly breathless numbers. It's possible because there's a motivation to do it. Simple as that. If we had a similar level of motivation to sequester our excess carbon we could start planning to do that tomorrow and have it done within a decade or three. You can't sequester all the worlds carbon in one place, just like you don't pull it all out of the ground in one place. Big problems seem less so when you realize that solutions are usually distributed.

yodon 5y ago

The existence of oil shows CO2 can be stored in solid or liquid form, but doesn't show we know how to convert CO2 into that stored form at scale or keep our hands off it once it's stored that way. It's easy to burn oil, it's hard to make it, and it's harder still to not burn it when you know it's readily available.

semi-extrinsic 5y ago
CO2 is in the dense supercritical state at the temperature and pressure conditions in storage reservoirs. It's density is between 750 and 850 kg/m3 then (water is 1000). You just have to compress it and pump it down there, and it will stay like that. Honestly, the storage part is a solved problem from the feasibility side. The remaining challenges are mainly cost optimization, across all of capture, transport and storage. And the biggest hurdle is forcing businesses to actually pay for the currently externalized cost of CO2 emissions.
- yodon 5y ago
  I agree with your thermodynamics, I'm just concerned about finding a volume big enough to store climatically meaningful amounts of CO2 in that form. 40 billion metric tons per year of CO2 in the form you describe is around 30 billion cubic meters, and you need to find that much storage volume every year just to keep things from getting worse. If you want to actually make a dent, like rolling things back to the year 2000 (which likely isn't enough, but is a real impact), that's more like 600 billion metric tons or 450 billion cubic meters. That's roughly equivalent to 400 mountains 5000 feet tall. It's a huge volume of material we're talking about finding a place to store if we're actually trying to make a real dent in climate change.
  - s1artibartfast 5y ago
    For context, Global Natural Gas production is approximately 4,000 billion cubic meters per year. To sequester the world's carbon emissions, we would need to move and store <1% the volume per year.
    - Robin_Message 5y ago
      That's apples to oranges: we don't store anything like a year's worth of gas. And anyone in Europe can tell you that natural gas transfer and storage is far from a solved problem.
      - s1artibartfast 5y ago
        The idea is not to actively store it, but dump it somewhere where it will store itself. Europe is a great example of how we have the technology to transfer huge amounts of gas, and the challenges are largely politics and capital. Nordstream #1 moves 60 billion m3 of gas 1,200 km and cost ~$10 billion
  - markcyffka 5y ago
    We also got calculations that yielded literal mountains ranges of carbonate... That's not to say carbonate cannot be part of the solution, but maybe it is unlikely to be the only solution.
  - idiotsecant 5y ago
    If you asked a pre-industrial person how in the world it would be possible to source, refine, and distribute enough crude oil to power the modern world they would quote some similarly breathless numbers. It's possible because there's a motivation to do it. Simple as that. If we had a similar level of motivation to sequester our excess carbon we could start planning to do that tomorrow and have it done within a decade or three. You can't sequester all the worlds carbon in one place, just like you don't pull it all out of the ground in one place. Big problems seem less so when you realize that solutions are usually distributed.