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I think the original article was looking at the proposition of off-grid energy use using purely solar, in which scenario seasonal variations matter From the ar

I think the original article was looking at the proposition of off-grid energy use using purely solar, in which scenario seasonal variations matter From the article "Even with these rough numbers it’s hard to see how anyone living any distance from the Equator is going to be able to justify the cost of installing enough batteries to go off-grid with a domestic rooftop solar PV installation."

jacquesm 11y ago
> Even with these rough numbers it’s hard to see how anyone living any distance from the Equator is going to be able to justify the cost of installing enough batteries to go off-grid with a domestic rooftop solar PV installation. If you go off grid on purely solar your backup is not a battery, your backup is a genset. It's a nonsense proposition leading to nonsense conclusions based on nonsense numbers. Very tiring.
- raesene4 11y ago
  I'd agree, I was just pointing out the basis that the author was coming from which was the reason why he was considering seasonal variations in battery calculations. With that said, from reading some articles about off-grid living, it's not outwith the bounds of possibility that people are looking at pure solar (or pure renewable anyway) off-grid living, for priniple-based reasons , rather than a more pragmatic rationale.
  - jacquesm 11y ago
    Only if they don't care about their lives. Look, I've lived off the grid for a number of years. 99% of the time things work just fine and all your plans come out. And then, in the middle of January there is a 9 day spell without wind and solar and you're going to have to fire up the genset. Tough, but preferable over having all your waterlines freeze due to 'principles'. Principles are nice to have but when you go off-grid out of principle the one principle you don't want to throw overboard is reliability and a good generator is worth gold when everything else you carefully planned out fails. If there is one thing that you can predict about the weather then it is that it is unpredictable.
    - codecamper 11y ago
      I guess a genset doesn't add much to the final bill?
      - jacquesm 11y ago
        A small one is better than nothing in a pinch and a 2 KW gas powered genset is a few hundred bucks. I went the overkill route (diesel, 6.5 KW) but I also had a machineshop attached to the house and it was nice to run the mill or the lathe without draining the battery in a couple of hours.
- ghshephard 11y ago
  I really thought the article was interesting - it highlighted precisely the fact that you are trying to make, which is you need a hybrid approach of energy sources, or focus on conserving, and that it's not feasible (today) to live your "typical" western life year-round using Solar+Battery. Plus, the author put quite a bit of work into using real data over multiple latitudes.
  - antimagic 11y ago
    The thing is though that right from the start the calculations make the assumption that the solar panels are sized in such a way that they capture just the right amount of energy over the course of the year. That means that you need to store every bit of energy that isn't immediately used, because it will be needed later. Back in the real world you wouldn't design your system that way. Instead, you would look at your worst case scenario - mid-winter, and calculate how many solar panels you would need to capture a day's worth of energy in one day. This would also tell you how large your battery would need to be. A prudent engineer would probably introduce a factor of 2 or so both in the size of the panel installation and the size of the battery to allow for a sequence of unusually dark days, but the multiples being talked about in the article are just ridiculous.
    - ghshephard 11y ago
      Thanks - for some reason that got totally by me. Now I'm just wondering if the author had an axe to grind, or this also got by them as well.

jacquesm 11y ago

> Even with these rough numbers it’s hard to see how anyone living any distance from the Equator is going to be able to justify the cost of installing enough batteries to go off-grid with a domestic rooftop solar PV installation. If you go off grid on purely solar your backup is not a battery, your backup is a genset. It's a nonsense proposition leading to nonsense conclusions based on nonsense numbers. Very tiring.

raesene4 11y ago
I'd agree, I was just pointing out the basis that the author was coming from which was the reason why he was considering seasonal variations in battery calculations. With that said, from reading some articles about off-grid living, it's not outwith the bounds of possibility that people are looking at pure solar (or pure renewable anyway) off-grid living, for priniple-based reasons , rather than a more pragmatic rationale.
- jacquesm 11y ago
  Only if they don't care about their lives. Look, I've lived off the grid for a number of years. 99% of the time things work just fine and all your plans come out. And then, in the middle of January there is a 9 day spell without wind and solar and you're going to have to fire up the genset. Tough, but preferable over having all your waterlines freeze due to 'principles'. Principles are nice to have but when you go off-grid out of principle the one principle you don't want to throw overboard is reliability and a good generator is worth gold when everything else you carefully planned out fails. If there is one thing that you can predict about the weather then it is that it is unpredictable.
  - codecamper 11y ago
    I guess a genset doesn't add much to the final bill?
    - jacquesm 11y ago
      A small one is better than nothing in a pinch and a 2 KW gas powered genset is a few hundred bucks. I went the overkill route (diesel, 6.5 KW) but I also had a machineshop attached to the house and it was nice to run the mill or the lathe without draining the battery in a couple of hours.
ghshephard 11y ago
I really thought the article was interesting - it highlighted precisely the fact that you are trying to make, which is you need a hybrid approach of energy sources, or focus on conserving, and that it's not feasible (today) to live your "typical" western life year-round using Solar+Battery. Plus, the author put quite a bit of work into using real data over multiple latitudes.
- antimagic 11y ago
  The thing is though that right from the start the calculations make the assumption that the solar panels are sized in such a way that they capture just the right amount of energy over the course of the year. That means that you need to store every bit of energy that isn't immediately used, because it will be needed later. Back in the real world you wouldn't design your system that way. Instead, you would look at your worst case scenario - mid-winter, and calculate how many solar panels you would need to capture a day's worth of energy in one day. This would also tell you how large your battery would need to be. A prudent engineer would probably introduce a factor of 2 or so both in the size of the panel installation and the size of the battery to allow for a sequence of unusually dark days, but the multiples being talked about in the article are just ridiculous.
  - ghshephard 11y ago
    Thanks - for some reason that got totally by me. Now I'm just wondering if the author had an axe to grind, or this also got by them as well.