• MxM111
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    fedilink
    110 months ago

    You seemed to be knowledgeable about this topic, so I have a question:

    I thought the process of obtaining hidrogen from the natural gas, naturally (pun not intended) captures all carbon as CO2, which is then can be stored somehow. Is it a valid path?

    What do you think about electrolyses?

    • @TropicalDingdong
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      310 months ago

      One kilogram of hydrogen is the energy equivalent of one gallon of gasoline, which produces 9.1 kg of CO2 when combusted.

      Carbon footprints are often reported in terms of energy. For example, power plants usually report carbon footprints in terms of kilowatt-hours (kWh). One million SCF of hydrogen contains 79,100 kilowatt hours of energy.

      This converts to 0.28 kg of carbon dioxide emissions associated with one kilowatt-hour of hydrogen production.

      This article lays it out, is based on up to date metrics for production, and was written by a qualified chemical engineer, in what I would consider, a very anodyne tone.

      The key take-away is here:

      On an apples-to-apples basis, it depends on several factors but it is likely that the conversion of hydrogen into power will have a carbon footprint greater than that of natural gas-fired power, but less than that of coal-fired power. However, it is possible in theory to capture the carbon emissions generated in the SMR process.

      Right now, today, you would be better off burning the natural gas in a power plant than turning it into hydrogen. Its better than coal. The CO2 could be captured, but that’s only a hypothetical. Currently, that isn’t part of the process, and doing so will incur an energy cost, at which point the ROI will likely be lower than coal.

      In conclusion, you should think of hydrogen as a green-washed fossil fuel, because that’s what it is.

      • @set_secret
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        110 months ago

        your gallon and kg combination gave me a TIA.

        Why not just explain it all in metric?

        • @TropicalDingdong
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          110 months ago

          1: I’m quoting the article

          2: In carbon accounting, its not uncommon at all (at least on the forestry side), to switch between some kind of standard or regional unit like board feet, or acres, whatever, and units of CO2e (CO2 equivalent), which are always international units. People have a direct understanding with something like a gallon of gasoline, whereas a unit of CO2 is abstract from the get-go.

          • @set_secret
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            10 months ago

            i and the rest of the world bar USA have zero clue what a gallon is. I’m assuming it’s some sort of arbitrary measument of something. possibly the depth of a hat?

            • @TropicalDingdong
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              110 months ago

              Do you not, in-fact, consider the capacity of your fuel tanks in units of hat depth?

              Curious…

              • @set_secret
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                210 months ago

                well of course i do, i mean it’s simple common sense.

      • Hypx
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        10 months ago

        Except you’ve actually debunked your own argument.

        At 9.3 kg of CO2 for one kg of H2, and assuming 110 km/kg of H2 (normal fuel economy for an FCEV), you get 84.5 grams of CO2 per km of driving.

        Meanwhile, a BEV gets anywhere from 70-370 grams per km, depending on dirtiness of the grid: https://shrinkthatfootprint.com/electric-car-emissions/

        In other words, an FCEV is comparable to a BEV when it comes to emissions. You can even double the numbers for the FCEV if you want to include possibilities like upstream losses or production. The numbers would still be very comparable to BEVs running on most grids.

        And this is the problem here: You’re so deep in your anti-hydrogen conspiracy theory that you failed to notice that the math works against you.