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Incorrect, demand peaks right as night starts and the sun goes down. See that peak [1] at 9pm? Battery backed solar is not even remotely feasible. To put this i

Incorrect, demand peaks right as night starts and the sun goes down. See that peak [1] at 9pm? Battery backed solar is not even remotely feasible. To put this in perspective, the USA alone uses ~11.5 TWh of electricty each day. A battery to last through the night is over 5,000 GWh. 1. https://b698061.smushcdn.com/698061/wp-content/uploads/2023/05/CASIO-duck-curve-circa-2013.jpg?lossy=1&strip=1&webp=1 https://b698061.smushcdn.com/698061/wp-content/uploads/2023/...

Retric 3y ago
There are several battery backed solar power plants in the US already built. Collocated Solar with batteries increases efficiency as DC from solar is used to directly charge batteries without the cost or losses associated with DC>AC>DC you would see if these where separate. LCOE is already below 60$/MWh because you only need batteries for a fraction of total production. https://atb.nrel.gov/electricity/2022/utility-scale_pv-plus-battery https://atb.nrel.gov/electricity/2022/utility-scale_pv-plus-...
- Manuel_D 3y ago
  Sure, but those battery backed solar plants usually only have 2-4 hours worth of storage. They're not actually producing full output throughout the night. The cost of batteries would skyrocket if countries actually tried to provision 12 hours of battery storage. Because the US alone uses 500 GWh of electricity each hour. This is greater than the global battery production figures in 2022 [1]. 1. https://www.spglobal.com/mobility/en/research-analysis/growth-of-liion-battery-manufacturing-capacity.html https://www.spglobal.com/mobility/en/research-analysis/growt...
  - Retric 3y ago
    You’re calculating that storage number as if the solar power plant would have produced power for 24 hours. To simplify if you have 8 hours of power and you store 1/2 of it you need 4h of storage. So our hypothetical 4GW solar power plant produces 2GW for 8 hours and 1 GW for 16. That already batter fits the demand curve than steady state output. However things get better if you instead consider real world demand and the actual production of solar panels being spread across the entire day a 4 hour of storage is close to perfect. Except, the real world isn’t a hypothetical 100% solar grid so 2h ends up working fine in most areas.
    - Manuel_D 3y ago
      Again, the demand curve is the opposite of what you claim: peak production happens during the night, at around 9 pm, not during the day. You'd need to supply more energy during periods of non-production, not less. You can't get away with 50% output at night, unless you have some other energy source picking up the slack. And remember, during the winter you're getting less than 12 hours of sunlight, maybe even less than that if you consider that cloud cover eliminates 75-90% of solar power output. These factors do depend on geography. Hotter climates do see more energy use during the day to power A/C. But on the flip side, colder climates see even more energy demand during the night to heat homes. And unfortunately this also coincides when solar is producing the least amount of energy due to fewer sunlight hours, axial tilt, and more cloud cover. There are niches solar can carve out: Las Vegas and Australia have loads of empty space, clear weather, and hydroelectricity that can fill in periods of non-production. But nuclear power is a much more flexible solution. All you really need is water to cool the reactor, and 80% of the population lives within a hundred miles of the coastline (you just need water, not fresh water).
      - nicoburns 3y ago
        Energy use for heating can be quite easily reduced just by insulating houses (and installing more efficient heating equipment such as heat pumps). Do we have any idea what the cause of that 9pm spike is? That seems like a bizarre time to be the peak to me (I can't work out what the primary energy users would be at that time).
        Manuel_D 3y ago
        Replacing gas heating with heat pumps is going to increase, not reduce, electricity use.
        Retric 3y ago
        Replacing gas heating with solar thermal is even cheaper and doesn’t. Electric heat pumps are viable when electricity is cheap or demand is low and you want AC, the more they drive up electric costs the more alternatives become viable. Net effect you tend to see them in areas where there’s a surplus of winter electricity which also tends to be places with minimal demand for heating like Virginia rather than Mane. 46% in South Carolina, 42% in North Carolina, 30% in Virginia etc: https://www.statista.com/statistics/1327164/share-of-households-unsing-central-heat-pumps-by-state-us/ https://www.statista.com/statistics/1327164/share-of-househo...
ComputerGuru 3y ago
That’s for March 31st, presumably in the northern hemisphere. I assume the curve looks dramatically different for July 31st.
- Manuel_D 3y ago
  The curve also looks dramatically different in January 31st. March is about the middle between summer and winter.
ZeroGravitas 3y ago
That's 'net load', so the graph doesn't show rooftop or grid solar or wind's contribution. You can see the difference here for today (choose a previous day if it's near the start of the day in California): https://www.caiso.com/TodaysOutlook/Pages/default.aspx#section-net-demand-trend https://www.caiso.com/TodaysOutlook/Pages/default.aspx#secti... The non-grid PV and wind peak is lowered, and shifted a couple of hours later. And that graph still doesn't show consumer and behind the meter commercial PV impact. Historically there was a double peak, one of which has been wiped out entirely.
- Manuel_D 3y ago
  The peak still occurs in the evening around 8-9pm. The chart I linked shows a drop in net demand around midday, due to solar's contribution. But my point is the mismatch between peak electricity demand and solar production, which is the same regardless.
  - ZeroGravitas 3y ago
    That's all from the grids perspective, they only count their own solar and wind. Here's an animated diagram that explicitly calls out BTM (behind-the-meter) solar: https://isonewswire.com/wp-content/uploads/2023/02/btm_forecast_animation_v3.gif https://isonewswire.com/wp-content/uploads/2023/02/btm_forec...
    - Manuel_D 3y ago
      Right, and you see where maximum demand is at 8pm (even before any solar was installed)? That peak isn't going down by provisioning more solar. Thanks for the gif, it explains exactly what I'm talking about.

Retric 3y ago

There are several battery backed solar power plants in the US already built. Collocated Solar with batteries increases efficiency as DC from solar is used to directly charge batteries without the cost or losses associated with DC>AC>DC you would see if these where separate. LCOE is already below 60$/MWh because you only need batteries for a fraction of total production. https://atb.nrel.gov/electricity/2022/utility-scale_pv-plus-battery https://atb.nrel.gov/electricity/2022/utility-scale_pv-plus-...

Manuel_D 3y ago
Sure, but those battery backed solar plants usually only have 2-4 hours worth of storage. They're not actually producing full output throughout the night. The cost of batteries would skyrocket if countries actually tried to provision 12 hours of battery storage. Because the US alone uses 500 GWh of electricity each hour. This is greater than the global battery production figures in 2022 [1]. 1. https://www.spglobal.com/mobility/en/research-analysis/growth-of-liion-battery-manufacturing-capacity.html https://www.spglobal.com/mobility/en/research-analysis/growt...
- Retric 3y ago
  You’re calculating that storage number as if the solar power plant would have produced power for 24 hours. To simplify if you have 8 hours of power and you store 1/2 of it you need 4h of storage. So our hypothetical 4GW solar power plant produces 2GW for 8 hours and 1 GW for 16. That already batter fits the demand curve than steady state output. However things get better if you instead consider real world demand and the actual production of solar panels being spread across the entire day a 4 hour of storage is close to perfect. Except, the real world isn’t a hypothetical 100% solar grid so 2h ends up working fine in most areas.
  - Manuel_D 3y ago
    Again, the demand curve is the opposite of what you claim: peak production happens during the night, at around 9 pm, not during the day. You'd need to supply more energy during periods of non-production, not less. You can't get away with 50% output at night, unless you have some other energy source picking up the slack. And remember, during the winter you're getting less than 12 hours of sunlight, maybe even less than that if you consider that cloud cover eliminates 75-90% of solar power output. These factors do depend on geography. Hotter climates do see more energy use during the day to power A/C. But on the flip side, colder climates see even more energy demand during the night to heat homes. And unfortunately this also coincides when solar is producing the least amount of energy due to fewer sunlight hours, axial tilt, and more cloud cover. There are niches solar can carve out: Las Vegas and Australia have loads of empty space, clear weather, and hydroelectricity that can fill in periods of non-production. But nuclear power is a much more flexible solution. All you really need is water to cool the reactor, and 80% of the population lives within a hundred miles of the coastline (you just need water, not fresh water).
    - nicoburns 3y ago
      Energy use for heating can be quite easily reduced just by insulating houses (and installing more efficient heating equipment such as heat pumps). Do we have any idea what the cause of that 9pm spike is? That seems like a bizarre time to be the peak to me (I can't work out what the primary energy users would be at that time).
      - Manuel_D 3y ago
        Replacing gas heating with heat pumps is going to increase, not reduce, electricity use.
        Retric 3y ago
        Replacing gas heating with solar thermal is even cheaper and doesn’t. Electric heat pumps are viable when electricity is cheap or demand is low and you want AC, the more they drive up electric costs the more alternatives become viable. Net effect you tend to see them in areas where there’s a surplus of winter electricity which also tends to be places with minimal demand for heating like Virginia rather than Mane. 46% in South Carolina, 42% in North Carolina, 30% in Virginia etc: https://www.statista.com/statistics/1327164/share-of-households-unsing-central-heat-pumps-by-state-us/ https://www.statista.com/statistics/1327164/share-of-househo...

ComputerGuru 3y ago

That’s for March 31st, presumably in the northern hemisphere. I assume the curve looks dramatically different for July 31st.

Manuel_D 3y ago
The curve also looks dramatically different in January 31st. March is about the middle between summer and winter.

ZeroGravitas 3y ago

That's 'net load', so the graph doesn't show rooftop or grid solar or wind's contribution. You can see the difference here for today (choose a previous day if it's near the start of the day in California): https://www.caiso.com/TodaysOutlook/Pages/default.aspx#section-net-demand-trend https://www.caiso.com/TodaysOutlook/Pages/default.aspx#secti... The non-grid PV and wind peak is lowered, and shifted a couple of hours later. And that graph still doesn't show consumer and behind the meter commercial PV impact. Historically there was a double peak, one of which has been wiped out entirely.

Manuel_D 3y ago
The peak still occurs in the evening around 8-9pm. The chart I linked shows a drop in net demand around midday, due to solar's contribution. But my point is the mismatch between peak electricity demand and solar production, which is the same regardless.
- ZeroGravitas 3y ago
  That's all from the grids perspective, they only count their own solar and wind. Here's an animated diagram that explicitly calls out BTM (behind-the-meter) solar: https://isonewswire.com/wp-content/uploads/2023/02/btm_forecast_animation_v3.gif https://isonewswire.com/wp-content/uploads/2023/02/btm_forec...
  - Manuel_D 3y ago
    Right, and you see where maximum demand is at 8pm (even before any solar was installed)? That peak isn't going down by provisioning more solar. Thanks for the gif, it explains exactly what I'm talking about.