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Electrolysis at scale has to happen for green hydrogen to replace coking coal in iron smelting/steelmaking (~9% of global carbon emissions)[1] and to replace st

Electrolysis at scale has to happen for green hydrogen to replace coking coal in iron smelting/steelmaking (~9% of global carbon emissions)[1] and to replace steam reformation of fossil methane for making ammonia, for fertilizer (~1%). Those applications don't require an elaborate transport infrastructure; just that the plants be located near large PV farms or vice versa. Why write "trillions" in capital letters? Is it supposed to be impressive? A trillion dollars is one percent of global GDP. Oil, fossil gas, and coal extraction cost 5 TRILLION dollars a year, and the infrastructure for their use (vehicles, boilers, etc.) cost TRILLIONS more. And that's just to offset depreciation. 1. An alternative to using hydrogen for iron smelting is direct electrolysis of molten iron ore, but that is at early research stages. It can't be rolled out globally in the next four decades; development will take longer than that.

AtlasBarfed 4y ago
Because current investment in hydrogen infrastructure is likely ONE MILLIONTH of that ... or more. As in it is so far behind that there is no feasible way to catch up. But mostly ecause numbers with lots of zeros are important to keep in mind.
- tuatoru 4y ago
  If it's growing at tenfold per year, that's only six years' growth. I don't know what the actual growth rate is, but I don't think there's cause for concern, except to coal miners. Edit: there aren't any material limitations. The current hotness is proton-exchange membrane technology; the coming thing is solid oxide electrolysis (promises lower cost); the century-old technology (that has been ignored for most of that time, so hasn't been properly cost-optimised) is alkaline electrolysis using caustic potash or caustic soda. Alkaline is slightly higher cost, but as I said no significant effort has been put into it for a while. There is no way we can ever run out of sodium.
  - AtlasBarfed 4y ago
    Yes, which is why CATL's sodium ion 160 wh/kg mass production in 2023 battery is such a big deal. Hydrogen can grow 10x from where it is now because it is paltry in size, but then, no way. But as you yourself point out, hydrogen is all research and prototypes, but EV / Solar / Batteries / Wind is production or near-production. At this point the planet needs what works now. But will hydrogen extraction/electrolysis ever be cheaper than grabbing it from methane? I doubt it. That's one of the big big big issues with hydrogen, the "green hydrogen" supply chain can be exposed to fraudulently sourced hydrogen. Don't assume regulatory controls will be in place everywhere, companies will simply arbitrage the lowest common denominator regulation or under the table it. It happens to this day with petroleum from Iran and Russia.
robocat 4y ago
Presumably the electricity network can often be used to transport the power, so only the hydrogen electrolysis plant needs to be near the industrial consumer. The possibility is very dependent on the network constraints to the load: there is often excess network capacity on many links or excess capacity at certain times of day, because the network is built to handle peak loads. There is also availability of capacity on network secondary-links that have reserved backup capacity (to handle failover from network primary-link failure). One major constraint for green power is locating it near a network node that can accept the power.
- tuatoru 4y ago
  Yes, although siting the electrolyzer at the PV farm uses DC from the modules directly, avoiding DC-AC inversion losses, transmission losses and AC-DC rectification losses. Having the smelter there too avoids hydrogen transport and storage costs. All that, of course, has to be balanced against ore transport and slag disposal costs.
  - robocat 4y ago
    Network and conversion losses are often surprisingly small. For example a 600km DC link in NZ[1] has total losses of 1.42% on the first 323MW and 3.30% on the next 753MW[2] (age of rectification & inverter equipment varies). There is AC to DC conversion at both ends, so that is equivalent. DC transmission losses are less than an AC segment would be (220kV AC to 350kV DC with 40km underwater). [1] https://wikipedia.org/wiki/HVDC_Inter-Island https://wikipedia.org/wiki/HVDC_Inter-Island [2] p23 of https://environment.govt.nz/assets/Publications/Files/Assessment-of-the-Impact-of-Flow-Alterations-on-Electricity-Generation.pdf https://environment.govt.nz/assets/Publications/Files/Assess...

AtlasBarfed 4y ago

Because current investment in hydrogen infrastructure is likely ONE MILLIONTH of that ... or more. As in it is so far behind that there is no feasible way to catch up. But mostly ecause numbers with lots of zeros are important to keep in mind.

tuatoru 4y ago
If it's growing at tenfold per year, that's only six years' growth. I don't know what the actual growth rate is, but I don't think there's cause for concern, except to coal miners. Edit: there aren't any material limitations. The current hotness is proton-exchange membrane technology; the coming thing is solid oxide electrolysis (promises lower cost); the century-old technology (that has been ignored for most of that time, so hasn't been properly cost-optimised) is alkaline electrolysis using caustic potash or caustic soda. Alkaline is slightly higher cost, but as I said no significant effort has been put into it for a while. There is no way we can ever run out of sodium.
- AtlasBarfed 4y ago
  Yes, which is why CATL's sodium ion 160 wh/kg mass production in 2023 battery is such a big deal. Hydrogen can grow 10x from where it is now because it is paltry in size, but then, no way. But as you yourself point out, hydrogen is all research and prototypes, but EV / Solar / Batteries / Wind is production or near-production. At this point the planet needs what works now. But will hydrogen extraction/electrolysis ever be cheaper than grabbing it from methane? I doubt it. That's one of the big big big issues with hydrogen, the "green hydrogen" supply chain can be exposed to fraudulently sourced hydrogen. Don't assume regulatory controls will be in place everywhere, companies will simply arbitrage the lowest common denominator regulation or under the table it. It happens to this day with petroleum from Iran and Russia.

robocat 4y ago

Presumably the electricity network can often be used to transport the power, so only the hydrogen electrolysis plant needs to be near the industrial consumer. The possibility is very dependent on the network constraints to the load: there is often excess network capacity on many links or excess capacity at certain times of day, because the network is built to handle peak loads. There is also availability of capacity on network secondary-links that have reserved backup capacity (to handle failover from network primary-link failure). One major constraint for green power is locating it near a network node that can accept the power.

tuatoru 4y ago
Yes, although siting the electrolyzer at the PV farm uses DC from the modules directly, avoiding DC-AC inversion losses, transmission losses and AC-DC rectification losses. Having the smelter there too avoids hydrogen transport and storage costs. All that, of course, has to be balanced against ore transport and slag disposal costs.
- robocat 4y ago
  Network and conversion losses are often surprisingly small. For example a 600km DC link in NZ[1] has total losses of 1.42% on the first 323MW and 3.30% on the next 753MW[2] (age of rectification & inverter equipment varies). There is AC to DC conversion at both ends, so that is equivalent. DC transmission losses are less than an AC segment would be (220kV AC to 350kV DC with 40km underwater). [1] https://wikipedia.org/wiki/HVDC_Inter-Island https://wikipedia.org/wiki/HVDC_Inter-Island [2] p23 of https://environment.govt.nz/assets/Publications/Files/Assessment-of-the-Impact-of-Flow-Alterations-on-Electricity-Generation.pdf https://environment.govt.nz/assets/Publications/Files/Assess...