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> hydrogen gas Which is unfortunate since the vast majority of our hydrogen is manufactured from fossil fuels. It's really almost laughable how many "solutio

> hydrogen gas Which is unfortunate since the vast majority of our hydrogen is manufactured from fossil fuels. It's really almost laughable how many "solutions" to emissions are ultimately accounting tricks. People keep arguing there are solutions but atmospheric CO2 continues to rise and an increasing rate. Planet doesn't care how clever your argument is for using "less" co2.

ncmncm 4y ago
Just because most current production of hydrogen is from fossil fuel does not mean that will remain true in the future. As solar electricity continues getting cheaper and catalysts improve improve, H2 production will shift to electrolysis from water.
- time_to_smile 4y ago
  The trouble is that this is the answer to every fossil fuel replacement problem and each of these requires more total energy than we're using. It also takes more energy to produce using solar, so now you need not just enough solar to replace current fossil fuels you need more. And this is true of every hand-wavy "we'll just replace it with solar!" answer. If our only usage of fossil fuels was to create hydrogen for industrial usage, you would be correct, this would be no concern. But we're no where near seeing this happen at the scales it needs to happen.
  - ncmncm 4y ago
    I don't know where you get the idea that it takes more energy to produce hydrogen using solar than NG, or that it means anything to say so. The cost of NG is not falling, but cost of solar PV generation capacity is. The cost of the NG->H2 process is not falling, but the cost of PV generation and hydrolysis equipment is, and their efficiency is improving. The cost of H2 electrolysis is almost all capital expenditure, with zero marginal cost, so as each increment of solar PV and electrolysis equipment comes online, the amount of H2 that can be produced per unit time for $0 extra input grows. We do not need to increase our H2 production, but there will be increasing value in doing so as its cost falls. All we are really lacking at this time is enough PV generating capacity to match demand, and enough electrolysis equipment to match demand. We just need to keep building out. Time would be on our side if global climate catastrophe and civilization collapse did not loom. We need to spend fast enough for the switchover to happen first.
    - cogman10 4y ago
      > I don't know where you get the idea that it takes more energy to produce hydrogen using solar than NG. Pulling H2 off of water takes input energy. Pulling H2 off of methane ultimately releases energy. That doesn't mean that electrolysis couldn't eventually become cheaper, but rather that processing natural gas to create H2 can require less energy since there is already energy in that carbon-hydrogen bond that gets released through processing.
      - ncmncm 4y ago
        And, as I already said, it is meaningless to compare them on that basis. What is meaningful is that H2 from NG consumes opex, where H2 from renewables does not consume opex.
        cogman10 4y ago
        opex as in operating expenses? I don't think we actually disagree here. I do think solar will be cheaper. I'm simply pointing out it burns more energy (as in, it requires more input energy, not capital). I'm sorry if that wasn't clear from my reply.

ncmncm 4y ago

Just because most current production of hydrogen is from fossil fuel does not mean that will remain true in the future. As solar electricity continues getting cheaper and catalysts improve improve, H2 production will shift to electrolysis from water.

time_to_smile 4y ago
The trouble is that this is the answer to every fossil fuel replacement problem and each of these requires more total energy than we're using. It also takes more energy to produce using solar, so now you need not just enough solar to replace current fossil fuels you need more. And this is true of every hand-wavy "we'll just replace it with solar!" answer. If our only usage of fossil fuels was to create hydrogen for industrial usage, you would be correct, this would be no concern. But we're no where near seeing this happen at the scales it needs to happen.
- ncmncm 4y ago
  I don't know where you get the idea that it takes more energy to produce hydrogen using solar than NG, or that it means anything to say so. The cost of NG is not falling, but cost of solar PV generation capacity is. The cost of the NG->H2 process is not falling, but the cost of PV generation and hydrolysis equipment is, and their efficiency is improving. The cost of H2 electrolysis is almost all capital expenditure, with zero marginal cost, so as each increment of solar PV and electrolysis equipment comes online, the amount of H2 that can be produced per unit time for $0 extra input grows. We do not need to increase our H2 production, but there will be increasing value in doing so as its cost falls. All we are really lacking at this time is enough PV generating capacity to match demand, and enough electrolysis equipment to match demand. We just need to keep building out. Time would be on our side if global climate catastrophe and civilization collapse did not loom. We need to spend fast enough for the switchover to happen first.
  - cogman10 4y ago
    > I don't know where you get the idea that it takes more energy to produce hydrogen using solar than NG. Pulling H2 off of water takes input energy. Pulling H2 off of methane ultimately releases energy. That doesn't mean that electrolysis couldn't eventually become cheaper, but rather that processing natural gas to create H2 can require less energy since there is already energy in that carbon-hydrogen bond that gets released through processing.
    - ncmncm 4y ago
      And, as I already said, it is meaningless to compare them on that basis. What is meaningful is that H2 from NG consumes opex, where H2 from renewables does not consume opex.
      - cogman10 4y ago
        opex as in operating expenses? I don't think we actually disagree here. I do think solar will be cheaper. I'm simply pointing out it burns more energy (as in, it requires more input energy, not capital). I'm sorry if that wasn't clear from my reply.