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Theoretically you could just electrolyze water on site using power from existing grid. It wouldn't be that much more difficult infrastructure wise than buildin

Theoretically you could just electrolyze water on site using power from existing grid. It wouldn't be that much more difficult infrastructure wise than building charging facilities for EV. However according to the diagram included on this article[1] the pipeline from AC power to usable thrust is 3x more efficient for battery vehicles currently. EDIT: forgot to link the article but I'm on my phone now. Some clever googling will find it for you if you're interested.

Scoundreller 7y ago
And they’ll have to deal with the pesky fact that hydrogen gas from natural gas is cheaper than H2 from electricity. So it’s either: 1) more nuclear plants in Germany (lol) 2) increased German dependence on Russian natural gas (lol)
- llampx 7y ago
  What happens to the carbon from natural gas once the hydrogen is extracted?
  - Scoundreller 7y ago
    Ultimately becomes CO2. Because it's produced centrally, you could collect it and do something with it or store it.
    - pfdietz 7y ago
      It's possible to just leave it as carbon. The energy needed to convert methane to carbon + H2 is much less (per unit H2) than that needed to convert water to O2 + H2.
  - azernik 7y ago
    There are experiments (currently underway in Germany) to extract hydrogen from natural gas without burning the resulting carbon, leaving behind graphite powder which can then be either buried or fed into carbon-composite manufacturing.
- the8472 7y ago
  If you buy electricity on the spot market it can be extremely cheap or even negative-priced. But the downside of that strategy is that you can only operate your facility for some times of the day.
  - ethbro 7y ago
    That's an interesting point, in aggregate. As we move towards more intermittent renewables, assuming the market remains intermittent, there's an entire new class of demand that's feasible. Essentially anything that "only needs power sometime in the next week, can soak up a semi-arbitrary amount of power, and can start/stop quickly (ideally grid-controlled)."
    - Scoundreller 7y ago
      I also think we haven't fully exploited interrmittent/responsive demand. I'd have no issues if a household or building's HVAC system, hot water system, electric car chargers ebbed and flowed their demand in response to supply. E.g. when I turn on my dishwasher, I don't care if it holds for 2 hours and then runs because the winds are calm now, but expected to pickup in 2 hours. I don't care if my hot water heater superheats water now because it's especially sunny or windy out. I don't care if my electric car chargers over the course of 8 hours in the evening, instead of charging quickly now. I don't care if my AC system makes the building a couple of degrees cooler now to thermal bank the excess supply before rates increase later.
      - ethbro 7y ago
        The issue seems to be that energy markets are a long way from achieving financial market levels of responsiveness. You're essentially increasing the number of market participants a couple orders of magnitude, and the system and existing players semi-understandably balk. On the other hand, without exposure to end users, the utility-driven pace of change is going to be glacial (by which I mean, we won't have glaciers anymore either).
        7y ago
rbf 7y ago
From what I've seen on current hydrogen fuelling stations having the capacity to actually refuel a significant amount of cars are limited (because tanks have to be repressurised), if you add electrolysis to this I imagine the fuelling rate is even more limited.

Scoundreller 7y ago

And they’ll have to deal with the pesky fact that hydrogen gas from natural gas is cheaper than H2 from electricity. So it’s either: 1) more nuclear plants in Germany (lol) 2) increased German dependence on Russian natural gas (lol)

llampx 7y ago
What happens to the carbon from natural gas once the hydrogen is extracted?
- Scoundreller 7y ago
  Ultimately becomes CO2. Because it's produced centrally, you could collect it and do something with it or store it.
  - pfdietz 7y ago
    It's possible to just leave it as carbon. The energy needed to convert methane to carbon + H2 is much less (per unit H2) than that needed to convert water to O2 + H2.
- azernik 7y ago
  There are experiments (currently underway in Germany) to extract hydrogen from natural gas without burning the resulting carbon, leaving behind graphite powder which can then be either buried or fed into carbon-composite manufacturing.
the8472 7y ago
If you buy electricity on the spot market it can be extremely cheap or even negative-priced. But the downside of that strategy is that you can only operate your facility for some times of the day.
- ethbro 7y ago
  That's an interesting point, in aggregate. As we move towards more intermittent renewables, assuming the market remains intermittent, there's an entire new class of demand that's feasible. Essentially anything that "only needs power sometime in the next week, can soak up a semi-arbitrary amount of power, and can start/stop quickly (ideally grid-controlled)."
  - Scoundreller 7y ago
    I also think we haven't fully exploited interrmittent/responsive demand. I'd have no issues if a household or building's HVAC system, hot water system, electric car chargers ebbed and flowed their demand in response to supply. E.g. when I turn on my dishwasher, I don't care if it holds for 2 hours and then runs because the winds are calm now, but expected to pickup in 2 hours. I don't care if my hot water heater superheats water now because it's especially sunny or windy out. I don't care if my electric car chargers over the course of 8 hours in the evening, instead of charging quickly now. I don't care if my AC system makes the building a couple of degrees cooler now to thermal bank the excess supply before rates increase later.
    - ethbro 7y ago
      The issue seems to be that energy markets are a long way from achieving financial market levels of responsiveness. You're essentially increasing the number of market participants a couple orders of magnitude, and the system and existing players semi-understandably balk. On the other hand, without exposure to end users, the utility-driven pace of change is going to be glacial (by which I mean, we won't have glaciers anymore either).
      - 7y ago

rbf 7y ago

From what I've seen on current hydrogen fuelling stations having the capacity to actually refuel a significant amount of cars are limited (because tanks have to be repressurised), if you add electrolysis to this I imagine the fuelling rate is even more limited.