5 ms·

>we might be able to even do this for air-conditioning, washing machines, or car-charging (if you have a PHEV or EV). No _might_ about it, this currently happe

>we might be able to even do this for air-conditioning, washing machines, or car-charging (if you have a PHEV or EV). No _might_ about it, this currently happens for A/C, and is just getting going for car charging (see EV Managed Charging as a category). Also some functions of commercial/industrial facilities that can be ramped more easily, eg shut off half of the hallway lighting in an office building. I think I recall things like rock crushers being turned off, but I might be misremembering that.

__MatrixMan__ 3y ago
Unfortunately, solar panels get less efficient when hot, which is when your AC demand increases. Ideally you could offset this by having people who aren't well positioned for panels do energy storage: Buy in the morning, sell back in the afternoon. Practically I don't think the utility companies are going to cut them in on a big enough part of the profits to incentivize them to do so.
- breischl 3y ago
  Sorry I stated my original point poorly, and it wasn't exactly what you were saying. My bad. Demand response for A/C tends to look more like pre-cooling before the hottest hours, then reduce demand during the hottest hours. So it's not about shifting demand towards maximum production, but rather shifting demand away from the demand peak (aka, peak shaving). So it's similar but a little different. >Practically I don't think the utility companies are going to cut them in on a big enough part of the profits to incentivize them to do so. The commercial version of what I stated in the previous paragraph (ie, demand response/peak shaving) empirically already happens, and has non-trivial dollars attached to it. Again, maybe not exactly what you're talking about, but it rhymes.
- duckmysick 3y ago
  > Unfortunately, solar panels get less efficient when hot, Less efficient by what factor?
  - edent 3y ago
    Based on my experience - about 12%. See https://shkspr.mobi/blog/2022/07/solar-efficiency-and-high-temperature/ https://shkspr.mobi/blog/2022/07/solar-efficiency-and-high-t... That will depend heavily on local conditions, type of panel, etc. Significant, but not devastating.
    - duckmysick 3y ago
      That's pretty cool! 10% was my educated guess. It's good to have some data points. Would you say the same holds across months? Say, would cooler May have better production than hotter July? Or is July still ahead because of more sunshine hours, offsetting the hot inefficiencies?
      - edent 3y ago
        It really depends on the weather. You can see my monthly generation at https://pvoutput.org/aggregate.jsp?id=83962&sid=74451&v=0&t=m https://pvoutput.org/aggregate.jsp?id=83962&sid=74451&v=0&t=... Sometimes May beats July, sometimes it doesn't. If you're interested, I have released all my panels' data at https://gitlab.com/edent/solar-data/ https://gitlab.com/edent/solar-data/
        duckmysick 3y ago
        Thanks. This is all very interesting, I love graphs like these. I see the pvoutput page didn't pick up some days in May and June 2020. I'm curious why, since I can see them on your .csv dumps.
        edent 3y ago
        Probably because my Internet connection went down.
      - stephen_g 3y ago
        I'm in a hot climate, I find in general with my system that the length of the day dominates over the loss in efficiency so December (southern hemisphere) is always the peak generation for me. January we usually have storms and rain due to the humidity so that's not usually as good, but it seems to be pretty reliably due to that shading from the cloudy and rainy weather more than heat.

__MatrixMan__ 3y ago

Unfortunately, solar panels get less efficient when hot, which is when your AC demand increases. Ideally you could offset this by having people who aren't well positioned for panels do energy storage: Buy in the morning, sell back in the afternoon. Practically I don't think the utility companies are going to cut them in on a big enough part of the profits to incentivize them to do so.

breischl 3y ago
Sorry I stated my original point poorly, and it wasn't exactly what you were saying. My bad. Demand response for A/C tends to look more like pre-cooling before the hottest hours, then reduce demand during the hottest hours. So it's not about shifting demand towards maximum production, but rather shifting demand away from the demand peak (aka, peak shaving). So it's similar but a little different. >Practically I don't think the utility companies are going to cut them in on a big enough part of the profits to incentivize them to do so. The commercial version of what I stated in the previous paragraph (ie, demand response/peak shaving) empirically already happens, and has non-trivial dollars attached to it. Again, maybe not exactly what you're talking about, but it rhymes.
duckmysick 3y ago
> Unfortunately, solar panels get less efficient when hot, Less efficient by what factor?
- edent 3y ago
  Based on my experience - about 12%. See https://shkspr.mobi/blog/2022/07/solar-efficiency-and-high-temperature/ https://shkspr.mobi/blog/2022/07/solar-efficiency-and-high-t... That will depend heavily on local conditions, type of panel, etc. Significant, but not devastating.
  - duckmysick 3y ago
    That's pretty cool! 10% was my educated guess. It's good to have some data points. Would you say the same holds across months? Say, would cooler May have better production than hotter July? Or is July still ahead because of more sunshine hours, offsetting the hot inefficiencies?
    - edent 3y ago
      It really depends on the weather. You can see my monthly generation at https://pvoutput.org/aggregate.jsp?id=83962&sid=74451&v=0&t=m https://pvoutput.org/aggregate.jsp?id=83962&sid=74451&v=0&t=... Sometimes May beats July, sometimes it doesn't. If you're interested, I have released all my panels' data at https://gitlab.com/edent/solar-data/ https://gitlab.com/edent/solar-data/
      - duckmysick 3y ago
        Thanks. This is all very interesting, I love graphs like these. I see the pvoutput page didn't pick up some days in May and June 2020. I'm curious why, since I can see them on your .csv dumps.
        edent 3y ago
        Probably because my Internet connection went down.
    - stephen_g 3y ago
      I'm in a hot climate, I find in general with my system that the length of the day dominates over the loss in efficiency so December (southern hemisphere) is always the peak generation for me. January we usually have storms and rain due to the humidity so that's not usually as good, but it seems to be pretty reliably due to that shading from the cloudy and rainy weather more than heat.