5 ms·

The problem isn't even shifting daytime generation to night; that is somewhat doable with energy storage. In Europe at least (and I assume much of the rest of t

The problem isn't even shifting daytime generation to night; that is somewhat doable with energy storage. In Europe at least (and I assume much of the rest of the world) the problem is shifting summer production to winter. UK demand in winter is nearly 2x higher than summer (and will grow even more with switching gas heating to heat pumps), at the same time solar output is ~10% of that at summer. Wind energy is higher but is unpredictable and in very cold snaps (when demand is greatest) tends to result in very low wind output. This problem is the biggest one to solve (and not sure how solvable it is). In essence it's possible to smooth out daily output with renewables, but annual output is very difficult. You are talking TWhs of storage requirement.

pfdietz 5y ago
Hydrogen solves that problem. The round trip efficiency is poor, but for seasonal storage efficiency doesn't matter very much.
- throwaway894345 5y ago
  We have lots of "solutions" (e.g., conventional batteries, flywheels, pumped hydro, etc), the critical question is cost. Where are the proven economical, grid-scale deployments of hydrogen storage? Last I checked, they were in their infancy, so while I'm rooting for it, characterizing hydrogen as a solution is facile.
  - pfdietz 5y ago
    There exist underground hydrogen storage caverns already. One was referenced elsewhere in the comments (supplying hydrogen to industrial users in the gulf states.) So, the technology exists. The major block for green hydrogen storage was the cost of electrolysers, but that is crashing now as well: China is selling alkaline electrolysers for under $300/kW. The hydrogen would be used in combined cycle plants. Hydrogen-burning combustion turbines have been available for 30 years. You might be misled by the apparent absence of installations for hydrogen grid storage, but understand that as long as natural gas is being used, it makes little sense to use hydrogen instead. That doesn't mean hydrogen can't work, it just means that natural gas (without CO2 charges) is for the moment cheaper.
    - throwaway894345 5y ago
      I'm aware of some storage caverns and have no doubts that the technology works, but everything I'm aware of suggests it's experimental with respect to the economics.
      - ncmncm 5y ago
        Experimental technology does not get billion-dollar orders. Factories for iron-air storage are being built today, to start supplying grid-scale storage in 2023. Everybody knows the demand is there and will remain there, so there is plenty of capital for anything known to work. But it takes time to build out. After costs shake out, build-out will concentrate on the cheapest alternatives, but everything already built will still work, and still be used, because the cost is capital cost. It will be a long time before the storage market is saturated and storage providers have to compete on prices.
      - pfdietz 5y ago
        It will be ready and waiting when the economic incentives needed to put it into place are there. These incentives by all evidence will be less than what would be needed to put nuclear into its place. BTW, if you object to hydrogen on these grounds, you must also object to nuclear on these grounds, and more strongly. This is especially the case if you imagine a nuclear powered world economy. You need to imagine a jump in technology more radical than for hydrogen storage -- either massive scale up of seawater uranium extraction (many orders of magnitude, from gram scale to megaton scale) or use of breeder reactors instead of burner reactors.
  - mrep 5y ago
    If you want proven tech, methane isn't much worse efficiency.
caoilte 5y ago
We don't need to switch summer production to winter if we keep improving grid inter-connectors. We will still need a lot more storage though. And insulation.
- ncmncm 5y ago
  Grid interconnection adds strategic risk, particularly for small countries. This is Europe's problem, particularly. It will be West Africa's, and South America's. China is building a submarine cable to South America for winter solar, but you may be sure they are also stockpiling coal for when the cable fails. They all need enough storage to not need interconnection, and then rely on interconnection to reduce cost and drawdown from storage.
- pfdietz 5y ago
  How does that work? Are you connecting Europe to Africa? Even Spain has a large winter/summer swing in insolation.
  - ncmncm 5y ago
    Most European connections to Africa have been cancelled as a consequence of massive photovoltaic cost reductions enabling local placement and overbuilding to compete. A few projects connecting Spain to African generation remain. Probably the most effective use for African solar energy production will be synthesis of hydrocarbons to be delivered by supertanker to high latitudes in winter, and for aircraft fuel.
    - pfdietz 5y ago
      Right. Which means that transmission in Europe cannot be anything other than an ineffective solution to seasonal variation in solar generation. The seasonal variation in solar energy available to the European grid will be large, and one either uses storage to deal with that, has extremely large amounts of demand that could be dispatched on a seasonal basis, or just wastes most of the summer production. What would end up happening instead would be the excess and otherwise curtailed production would create an irresistible force driving something -- like hydrogen production -- to soak up that otherwise wasted output.

pfdietz 5y ago

Hydrogen solves that problem. The round trip efficiency is poor, but for seasonal storage efficiency doesn't matter very much.

throwaway894345 5y ago
We have lots of "solutions" (e.g., conventional batteries, flywheels, pumped hydro, etc), the critical question is cost. Where are the proven economical, grid-scale deployments of hydrogen storage? Last I checked, they were in their infancy, so while I'm rooting for it, characterizing hydrogen as a solution is facile.
- pfdietz 5y ago
  There exist underground hydrogen storage caverns already. One was referenced elsewhere in the comments (supplying hydrogen to industrial users in the gulf states.) So, the technology exists. The major block for green hydrogen storage was the cost of electrolysers, but that is crashing now as well: China is selling alkaline electrolysers for under $300/kW. The hydrogen would be used in combined cycle plants. Hydrogen-burning combustion turbines have been available for 30 years. You might be misled by the apparent absence of installations for hydrogen grid storage, but understand that as long as natural gas is being used, it makes little sense to use hydrogen instead. That doesn't mean hydrogen can't work, it just means that natural gas (without CO2 charges) is for the moment cheaper.
  - throwaway894345 5y ago
    I'm aware of some storage caverns and have no doubts that the technology works, but everything I'm aware of suggests it's experimental with respect to the economics.
    - ncmncm 5y ago
      Experimental technology does not get billion-dollar orders. Factories for iron-air storage are being built today, to start supplying grid-scale storage in 2023. Everybody knows the demand is there and will remain there, so there is plenty of capital for anything known to work. But it takes time to build out. After costs shake out, build-out will concentrate on the cheapest alternatives, but everything already built will still work, and still be used, because the cost is capital cost. It will be a long time before the storage market is saturated and storage providers have to compete on prices.
    - pfdietz 5y ago
      It will be ready and waiting when the economic incentives needed to put it into place are there. These incentives by all evidence will be less than what would be needed to put nuclear into its place. BTW, if you object to hydrogen on these grounds, you must also object to nuclear on these grounds, and more strongly. This is especially the case if you imagine a nuclear powered world economy. You need to imagine a jump in technology more radical than for hydrogen storage -- either massive scale up of seawater uranium extraction (many orders of magnitude, from gram scale to megaton scale) or use of breeder reactors instead of burner reactors.
- mrep 5y ago
  If you want proven tech, methane isn't much worse efficiency.

caoilte 5y ago

We don't need to switch summer production to winter if we keep improving grid inter-connectors. We will still need a lot more storage though. And insulation.

ncmncm 5y ago
Grid interconnection adds strategic risk, particularly for small countries. This is Europe's problem, particularly. It will be West Africa's, and South America's. China is building a submarine cable to South America for winter solar, but you may be sure they are also stockpiling coal for when the cable fails. They all need enough storage to not need interconnection, and then rely on interconnection to reduce cost and drawdown from storage.
pfdietz 5y ago
How does that work? Are you connecting Europe to Africa? Even Spain has a large winter/summer swing in insolation.
- ncmncm 5y ago
  Most European connections to Africa have been cancelled as a consequence of massive photovoltaic cost reductions enabling local placement and overbuilding to compete. A few projects connecting Spain to African generation remain. Probably the most effective use for African solar energy production will be synthesis of hydrocarbons to be delivered by supertanker to high latitudes in winter, and for aircraft fuel.
  - pfdietz 5y ago
    Right. Which means that transmission in Europe cannot be anything other than an ineffective solution to seasonal variation in solar generation. The seasonal variation in solar energy available to the European grid will be large, and one either uses storage to deal with that, has extremely large amounts of demand that could be dispatched on a seasonal basis, or just wastes most of the summer production. What would end up happening instead would be the excess and otherwise curtailed production would create an irresistible force driving something -- like hydrogen production -- to soak up that otherwise wasted output.