6 ms·

> solar + storage providing power evenly over 24h (an unrealistic worst case) becomes economical. That's not the the worst case. Solar output varies by season.

> solar + storage providing power evenly over 24h (an unrealistic worst case) becomes economical. That's not the the worst case. Solar output varies by season. So you have to have enough storage for multiple weeks. This also means you have to greatly over-provison solar panels so that they not only provide power, but also enough to charge batteries.

epistasis 6y ago
No, you don't need storage for multiple weeks, that would be silly. Solar is so cheap now that already panel generation capacity is frequently getting oversized compared to the potential inverter output, to maximize costs. Future solar farm design will optimize seasonal generation capacity similarly; size your panels for the seasonal minimum, attach batteries, and you can have year round output of a firm amount with only hours worth of batteries.
- macspoofing 6y ago
  >No, you don't need storage for multiple weeks You have seasonal, and inter-seasonal variability in a solar and wind output. You need to account for that, in an economy that requires orders of magnitude more energy then being provided by renewables and is still electrifing. What do you mean it's silly? I've seen a few articles now where a baseline required battery storage is on the order of weeks. What do you mean a few hours is all that's required? What if you have a multi-day cloudy, wind-still weather? What do you do then????? >size your panels for the seasonal minimum, attach batteries No. You need to over-provison even for minimum seasonal output, because even in seasonal minimum you still need to charge your batteries. Winter is very long. > only hours worth of batteries If you don't mind constant blanks during periods of prolonged reduced wind/solar output...then sure. I don't what 'few hours' means - there's a day-night cycle every single day. Multi-day and highly variable multi-weeks where solar and wind output is minimal or none are relatively common. Here's what should give you pause and maybe make you reexamine your confidence - nobody is actually building out a solar/wind/battery infrastructure - nobody. We're essentially expanding natural gas use and complementing it with solar/wind (there's a reason why Germany is singing multi-decade contracts to ship Russian natural gas, and why every natural gas company is pushing renewables). Natural gas is not a transitional technology to renewables. It's the end-state for renewables.
pfdietz 6y ago
Very rare long term outages would not be covered by batteries. For that, you want a rock bottom low capital cost, even if it's much less efficient. Hydrogen makes sense for that use case, burned in turbines. For seasonal variation, simply overbuilding is also a possibility. No storage would be needed at all in Minnesota, for example, until renewables get to 70% of consumed electrical energy.
- macspoofing 6y ago
  >Hydrogen makes sense for that use case, burned in turbines. And where's hydrogen going to come from? You need to overprovision renewables so that they not only provide power for now, but also store enough power (via batteries or hydrogen or whatever) to get around daily, seasonal and inter-seasonal variability. And by the way, hydrogen from renewables is massively inefficient.
  - pfdietz 6y ago
    It would come from electrolysis of water, using renewable energy when that's in oversupply. Overprovisioning renewables for immediate consumption works in tandem with hydrogen, since it means there will be times excess power is available to make the hydrogen. The round trip efficiency of power->hydrogen->power through turbines will be maybe 33%. But this is FINE, if the capital cost of storing hydrogen in underground caverns is low enough and renewables are otherwise cheap enough (low LCoE).
    - Manfredo_1 6y ago
      If you're using caverns to reduce the capital cost of storing hydrogen, then you're ignoring a substantial amount of the real cost. Caverns are a geographically dependent feature, you might as well just say that we should use hydroelectricity as our main source of power.
      - pfdietz 6y ago
        Geological formations suitable for storage of hydrogen are quite widespread. They're basically identical to the formations that are already used to store natural gas.

epistasis 6y ago

No, you don't need storage for multiple weeks, that would be silly. Solar is so cheap now that already panel generation capacity is frequently getting oversized compared to the potential inverter output, to maximize costs. Future solar farm design will optimize seasonal generation capacity similarly; size your panels for the seasonal minimum, attach batteries, and you can have year round output of a firm amount with only hours worth of batteries.

macspoofing 6y ago
>No, you don't need storage for multiple weeks You have seasonal, and inter-seasonal variability in a solar and wind output. You need to account for that, in an economy that requires orders of magnitude more energy then being provided by renewables and is still electrifing. What do you mean it's silly? I've seen a few articles now where a baseline required battery storage is on the order of weeks. What do you mean a few hours is all that's required? What if you have a multi-day cloudy, wind-still weather? What do you do then????? >size your panels for the seasonal minimum, attach batteries No. You need to over-provison even for minimum seasonal output, because even in seasonal minimum you still need to charge your batteries. Winter is very long. > only hours worth of batteries If you don't mind constant blanks during periods of prolonged reduced wind/solar output...then sure. I don't what 'few hours' means - there's a day-night cycle every single day. Multi-day and highly variable multi-weeks where solar and wind output is minimal or none are relatively common. Here's what should give you pause and maybe make you reexamine your confidence - nobody is actually building out a solar/wind/battery infrastructure - nobody. We're essentially expanding natural gas use and complementing it with solar/wind (there's a reason why Germany is singing multi-decade contracts to ship Russian natural gas, and why every natural gas company is pushing renewables). Natural gas is not a transitional technology to renewables. It's the end-state for renewables.

pfdietz 6y ago

Very rare long term outages would not be covered by batteries. For that, you want a rock bottom low capital cost, even if it's much less efficient. Hydrogen makes sense for that use case, burned in turbines. For seasonal variation, simply overbuilding is also a possibility. No storage would be needed at all in Minnesota, for example, until renewables get to 70% of consumed electrical energy.

macspoofing 6y ago
>Hydrogen makes sense for that use case, burned in turbines. And where's hydrogen going to come from? You need to overprovision renewables so that they not only provide power for now, but also store enough power (via batteries or hydrogen or whatever) to get around daily, seasonal and inter-seasonal variability. And by the way, hydrogen from renewables is massively inefficient.
- pfdietz 6y ago
  It would come from electrolysis of water, using renewable energy when that's in oversupply. Overprovisioning renewables for immediate consumption works in tandem with hydrogen, since it means there will be times excess power is available to make the hydrogen. The round trip efficiency of power->hydrogen->power through turbines will be maybe 33%. But this is FINE, if the capital cost of storing hydrogen in underground caverns is low enough and renewables are otherwise cheap enough (low LCoE).
  - Manfredo_1 6y ago
    If you're using caverns to reduce the capital cost of storing hydrogen, then you're ignoring a substantial amount of the real cost. Caverns are a geographically dependent feature, you might as well just say that we should use hydroelectricity as our main source of power.
    - pfdietz 6y ago
      Geological formations suitable for storage of hydrogen are quite widespread. They're basically identical to the formations that are already used to store natural gas.