3 ms·

I think your math is realistic. We have to keep in mind that 6.9 isn’t yet the end user rate after grid fees, but still. There is also a ton of potential in d

I think your math is realistic. We have to keep in mind that 6.9 isn’t yet the end user rate after grid fees, but still. There is also a ton of potential in demand shaping by offering hourly prices to customers. The place where batteries fail is long-term, seasonal storage. The price per charge is still low, but an asset that takes 5000 years to amortise (one charge cycle per year) is not a competitive investment. So we will need other approaches here, where the substance that stores the energy is cheap and the cost is shifted onto the energy transforming device (this is e-fuels/ ammonia/ hydrogen)

Retric 3y ago
I’m not convinced we want significant seasonal storage as a separate system because depth of discharge impacts battery lifespan. So rather than having a singe battery doing nothing for 364 days a year and getting used one day you have a battery bank which gets discharged slightly more 1 day a year and recovers that deficit over some time period. For redundancy reasons you want excess generation capacity should something happen which would most of the time allow for a full charge soon afterwards. PS: individual wind locations also tend to get more power on specific time of the year which can offset seasonal issues.
- pfdietz 3y ago
  Using batteries for seasonal storage is crazy. E-fuels like hydrogen would be much more economical for that storage use case.
  - Retric 3y ago
    It’s not the battery being used for seasonal storage but the difference in rates of battery degradation. Suppose a normal discharge cycle costs 10c/kWh and a very deep discharge costs 100c/kWh to access that last 10%. That means there are energy reserves unacceptably expensive for normal operations, but it also means simply operating batteries efficiently automatically creates reserve capacity which is the entire point of dedicated seasonal storage. Put another way if you design a 1TWh battery for daily use it’s going to have a 0.1TWh reserve capacity just sitting there. This isn’t a lot of power across a full season, but it address seasonal storage in terms of short term abnormal peaks like heatwaves. PS: Proponents of seasonal storage argue for seasonal deficits in production rather than short term gaps. However, the daily variability of renewable production promotes significant excess generation capacity.
    - konschubert 3y ago
      Yes, what you're saying works. But only for short term outlier events, not storing power from summer for winter.
      - Retric 3y ago
        We can’t predict seasonal demand that accurately so trying to use a finite reserve for anything but outlier events is risky. Plan for a large deficit and the infrastructure you create to fill that reserve is sitting around in the off season reducing the size of your deficit. Plan for a small one and your estimate may be wildly inaccurate. What’s left for “seasonal storage” is to cover gaps in production from extreme outlier events using surplus production. That is useful, but also largely covered by battery power as I just covered. Granted if someone comes up with cheap enough seasonal storage it might have a place, but that’s a possibility not a guarantee.
        konschubert 3y ago
        If you use Ammonia as fuel, you can ship it worldwide in an energy crunch.
angiosperm 3y ago
There will be no need for "long-term, seasonal storage". We only need enough storage to last until a shipment of synthetic anhydrous ammonia, ordered from a nearby wind farm or from a solar farm in the tropics, can be delivered, to be burned in an existing combined-cycle turbine. That storage is some mix of batteries and tanked ammonia. Well-provisioned solar farms can synthesize and tank their own ammonia during periods of excess production, and sell excess (over what local tankage holds) on the open market.
- konschubert 3y ago
  I mention ammonia in my comment. I think we agree.

Retric 3y ago

I’m not convinced we want significant seasonal storage as a separate system because depth of discharge impacts battery lifespan. So rather than having a singe battery doing nothing for 364 days a year and getting used one day you have a battery bank which gets discharged slightly more 1 day a year and recovers that deficit over some time period. For redundancy reasons you want excess generation capacity should something happen which would most of the time allow for a full charge soon afterwards. PS: individual wind locations also tend to get more power on specific time of the year which can offset seasonal issues.

pfdietz 3y ago
Using batteries for seasonal storage is crazy. E-fuels like hydrogen would be much more economical for that storage use case.
- Retric 3y ago
  It’s not the battery being used for seasonal storage but the difference in rates of battery degradation. Suppose a normal discharge cycle costs 10c/kWh and a very deep discharge costs 100c/kWh to access that last 10%. That means there are energy reserves unacceptably expensive for normal operations, but it also means simply operating batteries efficiently automatically creates reserve capacity which is the entire point of dedicated seasonal storage. Put another way if you design a 1TWh battery for daily use it’s going to have a 0.1TWh reserve capacity just sitting there. This isn’t a lot of power across a full season, but it address seasonal storage in terms of short term abnormal peaks like heatwaves. PS: Proponents of seasonal storage argue for seasonal deficits in production rather than short term gaps. However, the daily variability of renewable production promotes significant excess generation capacity.
  - konschubert 3y ago
    Yes, what you're saying works. But only for short term outlier events, not storing power from summer for winter.
    - Retric 3y ago
      We can’t predict seasonal demand that accurately so trying to use a finite reserve for anything but outlier events is risky. Plan for a large deficit and the infrastructure you create to fill that reserve is sitting around in the off season reducing the size of your deficit. Plan for a small one and your estimate may be wildly inaccurate. What’s left for “seasonal storage” is to cover gaps in production from extreme outlier events using surplus production. That is useful, but also largely covered by battery power as I just covered. Granted if someone comes up with cheap enough seasonal storage it might have a place, but that’s a possibility not a guarantee.
      - konschubert 3y ago
        If you use Ammonia as fuel, you can ship it worldwide in an energy crunch.

angiosperm 3y ago

There will be no need for "long-term, seasonal storage". We only need enough storage to last until a shipment of synthetic anhydrous ammonia, ordered from a nearby wind farm or from a solar farm in the tropics, can be delivered, to be burned in an existing combined-cycle turbine. That storage is some mix of batteries and tanked ammonia. Well-provisioned solar farms can synthesize and tank their own ammonia during periods of excess production, and sell excess (over what local tankage holds) on the open market.

konschubert 3y ago
I mention ammonia in my comment. I think we agree.