• theneverfox@pawb.social
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    9 hours ago

    I get what you’re saying, it sounds very reasonable conceptually. But the problem is that this is a chain so riddled with weak links it’s infeasible

    You’re right about biofuel… Except that biofuel is already refined biomass. The water is already removed, usually to become as close to pure hydrocarbons as possible. That’s a far more efficient CO2 sink than pure CO2, because the oxygen component is in the atmosphere

    It’s insane to burn biofuels to lower atmospheric CO2.

    And as far as the process being non-destructive… This technology was developed to use pressured CO2 to break smaller pockets in the rock, it’s like using a pressure chamber to deflate foam. Except the rocks aren’t plastic until your get a whole lot deeper, and the amount of pressure means the whole well is being pressurized beyond a level it was ever at naturally

    Can a big cavity in the Earth store gasses? Sure. Can an oil well? Maybe… But so far, the answer is it leaks

    As for your last point… If you instead ask if we should cram biofuels in the ground? That’s a way better idea, there’s something to it. It’s not a solution, it doesn’t scale to the levels where we can keep using fossil fuels everywhere, but it would sequester C02 very effectively. Kind of like it was before we dug it up and burned it

    • Rivalarrival@lemmy.today
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      6 hours ago

      You’re right about biofuel… Except that biofuel is already refined biomass. The water is already removed, usually to become as close to pure hydrocarbons as possible.

      Hydrocarbons.

      Chains of hydrogen and carbon.

      Your comment demonstrates you’re not fully understanding the chemistry of the combustion. If you remove the “water” I am talking about, you wouldn’t have a hydrocarbon. You would have only carbon.

      The “water” I am talking about is the “hydro” part of the “hydrocarbon”. That “hydro” does not become CO2 when it burns. That “hydro” becomes H2O.

      When burning lighter hydrocarbons, the majority of the exhaust in the stack is actually water vapor rather than CO2. Putting that hydrogen into the ground, unburnt, provides no additional benefit over putting just the CO2 into the ground. It merely fills up the reservoir faster, and requires even more energy for the same amount of carbon sequestration. Burning that biomass, it is (theoretically) possible for the energy recovered (after powering sequestration operations) to be a net positive.

      Sequestering the unburned biofuel without recovering that energy, the operation must be a net negative.

      • theneverfox@pawb.social
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        4 hours ago

        Chains of hydrogen and carbon.

        Yes, hydrogen, the smaller possible molecule, and carbon, which is smaller and lighter then oxygen

        Hydrocsrbon chains are the most efficient way to store carbon, aside from something like graphite.

        Who cares what it becomes when you burn it? CO2 is obviously not the optimal carbon sink, even before you start considering things like long term stability

        • Rivalarrival@lemmy.today
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          4 hours ago

          Hydrocsrbon chains are the most efficient way to store carbo

          Volumetric efficiency is not the relevant metric. Energy efficiency is much more important. The process you describe requires far greater energy input to complete the sequestration.

          Furthermore, the physical properties are a problem. Biomass appropriate to this process is conveyed as a flammable, pelletized solid; CO2 is an inert fluid. One of these can be pumped via pipeline into empty subterranean reservoirs; the other cannot.