3 ms·

But the point isn’t that it’s “better” it’s just that gas (really only H2) provides the volume of storage to meaningfully transfer energy between seasons. It’s

But the point isn’t that it’s “better” it’s just that gas (really only H2) provides the volume of storage to meaningfully transfer energy between seasons. It’s mostly about capacity not about efficiency

ben_w 3y ago
If you need to fill a 20 hour storage system in 4 hours of sunlight, you care about how cheap the electricity is to generate and overproduce accordingly in better seasons. PV is cheap, and also not the only renewable so it may not even be as bad as 20:4. If you need to fill a 6 month night storage system with the sunlight from the other 6 months, instead of overproducing in summer you care about the storage being relatively stable and dense enough you don't run out of space. There may well be enough space, though at the scales that matter you'd need a lot of pipes or transmission lines depending on where you want the hydrogen powered generators, and a good electricity grid diminishes the need to store it anyway (a sufficiently good grid, 1m^2 aggregate cross section, doesn't even need any storage, because the planet is a sphere). Given how many people react as badly to hydrogen as to nuclear, just replacing Chernobyl with the Hindenburg and a misunderstanding about hydrogen bombs, I think sufficient storage will be tricky politically even if you solve all the technical issues. If you see a way to make it happen anyway, go for it. A plurality of solutions makes black swan correlated failures less damaging.
- hnaccount_rng 3y ago
  Guess what: we already have the storage capacity for that. We currently have something like 200TWh of gas storage. Once we don’t need that anymore for heating (give it 30 years) it’s free for hydrogen storage. This pretty much selects the locations for the grid-scale electrolyze installations. They must be either next to the storage sites or along the pipes. The latter already covers significant parts of Germany. Yes it’s inefficient, I’d be surprised if you even get 50% roundtrip efficiency, but it’s effectively free (at least compared to build battery capacity or nuclear power plants).
  - ben_w 3y ago
    > it’s free for hydrogen storage If only chemistry was so forgiving. The existing methane infrastructure isn't nothing, but it's also (from everything I've heard whenever this comes up) not everything either. OTOH, I have heard hydrogen is a lot friendlier when mixed with methane, so I assume this will still be very useful when transitioning to whatever comes next.
    - hnaccount_rng 3y ago
      Sure the storage tanks aren’t completely tight, so you will have some amount of leakage. But that’s (afaiu) mostly a problem of the distribution network. The tanks themselves are rather small and even if they leak 20% of their capacity.. who cares? You still get 200+TWh storage (because H2 is more energy dense than LNG) and you shouldn’t burn it either. Just use the reverse process to get electricity back. Yes _those_ plants aren’t there yet. They will have to be build. But that’s much less of a problem (10-20 locations) than upgrading all of the distribution network and all the heaters in every building! We will have to move away from gas-to-buildings though and that will require an upgrade in like 60% of the buildings. Industry is much less of a problem, because at the end of the day, their consumption is much less seasonally influenced (2x, rather than 10x) and only about 1/3 of total gas consumption anyways. So deal with the 2/3 block first. Then chase the rest

ben_w 3y ago

If you need to fill a 20 hour storage system in 4 hours of sunlight, you care about how cheap the electricity is to generate and overproduce accordingly in better seasons. PV is cheap, and also not the only renewable so it may not even be as bad as 20:4. If you need to fill a 6 month night storage system with the sunlight from the other 6 months, instead of overproducing in summer you care about the storage being relatively stable and dense enough you don't run out of space. There may well be enough space, though at the scales that matter you'd need a lot of pipes or transmission lines depending on where you want the hydrogen powered generators, and a good electricity grid diminishes the need to store it anyway (a sufficiently good grid, 1m^2 aggregate cross section, doesn't even need any storage, because the planet is a sphere). Given how many people react as badly to hydrogen as to nuclear, just replacing Chernobyl with the Hindenburg and a misunderstanding about hydrogen bombs, I think sufficient storage will be tricky politically even if you solve all the technical issues. If you see a way to make it happen anyway, go for it. A plurality of solutions makes black swan correlated failures less damaging.

hnaccount_rng 3y ago
Guess what: we already have the storage capacity for that. We currently have something like 200TWh of gas storage. Once we don’t need that anymore for heating (give it 30 years) it’s free for hydrogen storage. This pretty much selects the locations for the grid-scale electrolyze installations. They must be either next to the storage sites or along the pipes. The latter already covers significant parts of Germany. Yes it’s inefficient, I’d be surprised if you even get 50% roundtrip efficiency, but it’s effectively free (at least compared to build battery capacity or nuclear power plants).
- ben_w 3y ago
  > it’s free for hydrogen storage If only chemistry was so forgiving. The existing methane infrastructure isn't nothing, but it's also (from everything I've heard whenever this comes up) not everything either. OTOH, I have heard hydrogen is a lot friendlier when mixed with methane, so I assume this will still be very useful when transitioning to whatever comes next.
  - hnaccount_rng 3y ago
    Sure the storage tanks aren’t completely tight, so you will have some amount of leakage. But that’s (afaiu) mostly a problem of the distribution network. The tanks themselves are rather small and even if they leak 20% of their capacity.. who cares? You still get 200+TWh storage (because H2 is more energy dense than LNG) and you shouldn’t burn it either. Just use the reverse process to get electricity back. Yes _those_ plants aren’t there yet. They will have to be build. But that’s much less of a problem (10-20 locations) than upgrading all of the distribution network and all the heaters in every building! We will have to move away from gas-to-buildings though and that will require an upgrade in like 60% of the buildings. Industry is much less of a problem, because at the end of the day, their consumption is much less seasonally influenced (2x, rather than 10x) and only about 1/3 of total gas consumption anyways. So deal with the 2/3 block first. Then chase the rest