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> You have solar panels that generate 100GW average, i.e. 200GW during sunlight and nothing at night. You have batteries to match this up with the daily load.

> You have solar panels that generate 100GW average, i.e. 200GW during sunlight and nothing at night. You have batteries to match this up with the daily load. And that amount of batteries is absolutely massive. To put this in perspective, the US uses about 500 GW of electricity, or about 12 TWh per day. That's 6,000 GWh for just the United States. This is an incredible amount of storage, over 10x the annual global battery production. This is why talking about "average production" of intermittent sources is simplistic. You need to dig into the degree of overproduction and storage required to even out that intermittency. But including those factors makes renewables way more expensive, which is why people don't like to talk about these factors.

AnthonyMouse 3y ago
> This is an incredible amount of storage, over 10x the annual global battery production. It's a lot. Battery production would have to increase. But it is increasing, and it's not an impossible amount. You also cut it to less than half by doing the thing mentioned above, because the daytime load is higher anyway. If 40% of the generation comes from nuclear, that's 80% of the nighttime load and now you only need 20% as many batteries.
- Manuel_D 3y ago
  > It's a lot. Battery production would have to increase. But it is increasing, and it's not an impossible amount. Is it? Global battery production is about 500 GWh per year. A single digit percentage of that is going towards grid storage, it's mostly used for EVs and electronics. Even if we completely halted EV production, and dedicated 100% of global battery production to grid storage it'd take over a decade to just satisfy the United States' grid storage requirements. And that's just for diurnal storage, not seasonal storage. And again, that's dedicating 100% of global battery production to just one country. While battery production is increasing, so is electricity use. As transportation and other industries decarbonized, and as poor countries grow richer, electricity use is going to rise and so will the storage requirements. > because the daytime load is higher anyway Nope, in fact it's the opposite. Load typically peaks after sundown, at around 8pm. This is why solving the duck curve is so hard. Solar produces no energy during peak demand: https://en.m.wikipedia.org/wiki/Duck_curve https://en.m.wikipedia.org/wiki/Duck_curve
  - AnthonyMouse 3y ago
    > A single digit percentage of that is going towards grid storage, it's mostly used for EVs and electronics. That's fine, it makes sense to put it in EVs because EVs are de facto grid storage. You charge them during the part of the day with the most surplus generation and they even out the curves. > Even if we completely halted EV production, and dedicated 100% of global battery production to grid storage it'd take over a decade to just satisfy the United States' grid storage requirements. That's assuming production doesn't increase at all, and that you want a 100% renewable US grid instead of e.g. 60%. > And that's just for diurnal storage, not seasonal storage. Batteries aren't suitable for seasonal storage. Their contribution is to smooth out the load. Suppose during a cloudy week you would have a 50GW shortfall from 6PM to 10PM and a 10GW shortfall from 12PM to 6PM, but a 20GW surplus from 8AM to 12PM. Well then what you really have is 7.5GW average shortfall and by smoothing out the load with batteries can get by with 7.5GW of peaker plants that week, instead of needing 50GW at 8PM which then sits idle from 10PM to noon. > While battery production is increasing, so is electricity use. The main driver of this is electrifying transportation. But because cars have built-in storage, you can charge your car during daylight and substantially all of the new generation capacity can be renewables without encountering short-term intermittency issues. > Nope, in fact it's the opposite. Load typically peaks after sundown, at around 8pm. You can take a look at your own graph. The load during peak solar generation (~3PM) is >25GW, compared to ~20GW after midnight, and that's during the autumn rather than the summer. Air conditioning load aligns extremely well with solar generation. The peak load is around 8PM, but the peak load and the minimum load are both after dark, and the daytime average is higher than the nighttime average.
    - Manuel_D 3y ago
      EVs can only be used as storage under very specific circumstances. It assumes people drive to the work in the morning have charging stations at work, and don't commute very far. In reality lots of people don't have charging stations at work, and charge their cars in the evening when solar isn't producing. Also, there's loads of people doing errands during the day, or utility vehicles transporting cargo. These are going to be used consistently through the day and charged at night. Electric semi trucks aren't going to be helpful for grid storage. And they burn a lot more energy than a passenger sedan. And lastly, few grid operators are going to accept that their grid storage may drive away on masse during the holidays. > Suppose during a cloudy week you would have a 50GW shortfall from 6PM to 10PM and a 10GW shortfall from 12PM to 6PM, but a 20GW surplus from 8AM to 12PM During a cloudy week, you're going to have a shortfall all the time. Solar drops to 10-25% effectiveness with cloud cover: https://www.solarreviews.com/blog/do-solar-panels-work-on-cloudy-days-or-at-night#:~:text=Expect%20them%20to%20produce%2010%20to%2025%25%20of%20their%20normal,thick%20the%20cloud%20cover%20is https://www.solarreviews.com/blog/do-solar-panels-work-on-cl.... > The load during peak solar generation (~3PM) is >25GW, compared to ~20GW after midnight, and that's during the autumn rather than the summer. But again, peak demand isn't at midnight it's at 8pm. You can't just hand-wave away the challenge of meeting peak demand when intermittent sources aren't producing. > Air conditioning load aligns extremely well with solar generation. And it aligns even worse during the Winter: solar is producing the least amount of energy, cloud cover is at its greatest extent. Most homes are heated by gas, and when that gets decarbonized it's going to put even more load during the worst time of the year for renewables. Definitely, rooftop solar is a great addition and a good way to reduce load due to air conditioning. It comports with what I've been saying this whole thread: intermittent sources are good when used opportunistically to supplement a grid primarily powered by non-intermittent sources. The downsides of intermittency are too great to be used as a primary source of energy, though.

AnthonyMouse 3y ago

> This is an incredible amount of storage, over 10x the annual global battery production. It's a lot. Battery production would have to increase. But it is increasing, and it's not an impossible amount. You also cut it to less than half by doing the thing mentioned above, because the daytime load is higher anyway. If 40% of the generation comes from nuclear, that's 80% of the nighttime load and now you only need 20% as many batteries.

Manuel_D 3y ago
> It's a lot. Battery production would have to increase. But it is increasing, and it's not an impossible amount. Is it? Global battery production is about 500 GWh per year. A single digit percentage of that is going towards grid storage, it's mostly used for EVs and electronics. Even if we completely halted EV production, and dedicated 100% of global battery production to grid storage it'd take over a decade to just satisfy the United States' grid storage requirements. And that's just for diurnal storage, not seasonal storage. And again, that's dedicating 100% of global battery production to just one country. While battery production is increasing, so is electricity use. As transportation and other industries decarbonized, and as poor countries grow richer, electricity use is going to rise and so will the storage requirements. > because the daytime load is higher anyway Nope, in fact it's the opposite. Load typically peaks after sundown, at around 8pm. This is why solving the duck curve is so hard. Solar produces no energy during peak demand: https://en.m.wikipedia.org/wiki/Duck_curve https://en.m.wikipedia.org/wiki/Duck_curve
- AnthonyMouse 3y ago
  > A single digit percentage of that is going towards grid storage, it's mostly used for EVs and electronics. That's fine, it makes sense to put it in EVs because EVs are de facto grid storage. You charge them during the part of the day with the most surplus generation and they even out the curves. > Even if we completely halted EV production, and dedicated 100% of global battery production to grid storage it'd take over a decade to just satisfy the United States' grid storage requirements. That's assuming production doesn't increase at all, and that you want a 100% renewable US grid instead of e.g. 60%. > And that's just for diurnal storage, not seasonal storage. Batteries aren't suitable for seasonal storage. Their contribution is to smooth out the load. Suppose during a cloudy week you would have a 50GW shortfall from 6PM to 10PM and a 10GW shortfall from 12PM to 6PM, but a 20GW surplus from 8AM to 12PM. Well then what you really have is 7.5GW average shortfall and by smoothing out the load with batteries can get by with 7.5GW of peaker plants that week, instead of needing 50GW at 8PM which then sits idle from 10PM to noon. > While battery production is increasing, so is electricity use. The main driver of this is electrifying transportation. But because cars have built-in storage, you can charge your car during daylight and substantially all of the new generation capacity can be renewables without encountering short-term intermittency issues. > Nope, in fact it's the opposite. Load typically peaks after sundown, at around 8pm. You can take a look at your own graph. The load during peak solar generation (~3PM) is >25GW, compared to ~20GW after midnight, and that's during the autumn rather than the summer. Air conditioning load aligns extremely well with solar generation. The peak load is around 8PM, but the peak load and the minimum load are both after dark, and the daytime average is higher than the nighttime average.
  - Manuel_D 3y ago
    EVs can only be used as storage under very specific circumstances. It assumes people drive to the work in the morning have charging stations at work, and don't commute very far. In reality lots of people don't have charging stations at work, and charge their cars in the evening when solar isn't producing. Also, there's loads of people doing errands during the day, or utility vehicles transporting cargo. These are going to be used consistently through the day and charged at night. Electric semi trucks aren't going to be helpful for grid storage. And they burn a lot more energy than a passenger sedan. And lastly, few grid operators are going to accept that their grid storage may drive away on masse during the holidays. > Suppose during a cloudy week you would have a 50GW shortfall from 6PM to 10PM and a 10GW shortfall from 12PM to 6PM, but a 20GW surplus from 8AM to 12PM During a cloudy week, you're going to have a shortfall all the time. Solar drops to 10-25% effectiveness with cloud cover: https://www.solarreviews.com/blog/do-solar-panels-work-on-cloudy-days-or-at-night#:~:text=Expect%20them%20to%20produce%2010%20to%2025%25%20of%20their%20normal,thick%20the%20cloud%20cover%20is https://www.solarreviews.com/blog/do-solar-panels-work-on-cl.... > The load during peak solar generation (~3PM) is >25GW, compared to ~20GW after midnight, and that's during the autumn rather than the summer. But again, peak demand isn't at midnight it's at 8pm. You can't just hand-wave away the challenge of meeting peak demand when intermittent sources aren't producing. > Air conditioning load aligns extremely well with solar generation. And it aligns even worse during the Winter: solar is producing the least amount of energy, cloud cover is at its greatest extent. Most homes are heated by gas, and when that gets decarbonized it's going to put even more load during the worst time of the year for renewables. Definitely, rooftop solar is a great addition and a good way to reduce load due to air conditioning. It comports with what I've been saying this whole thread: intermittent sources are good when used opportunistically to supplement a grid primarily powered by non-intermittent sources. The downsides of intermittency are too great to be used as a primary source of energy, though.