9 ms·

No, we have not. Half of the current cost is due to installation and labor, so any weight reductions will have a huge impact on cost. Perovskite solar cells hav

No, we have not. Half of the current cost is due to installation and labor, so any weight reductions will have a huge impact on cost. Perovskite solar cells have the opportunity to have a 10 X weight reduction.

Denvercoder9 2y ago
How much of that cost is related to the physical handling of the panels themselves, and not the electrical installation, though? Weight reduction isn't going to help there.
- mensetmanusman 2y ago
  It’s propagates through the supply chain, loading, logistics, wear on vehicle transport etc. We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves.
  - deleted 2y ago
    [deleted]
  - lompad 2y ago
    The currents and voltages involved are going to make that a non-starter. Do you really want random people messing with those? The solar inverters are also sized that big for a reason. At least in countries with strong regulations around working with electricity this is simply not going to be feasible. I've been in the PV business for some time now and seen a person get killed by it. It's not pretty. Still remembering that smell of burnt flesh... Now, to be fair, that was at a 12MW-installation, not on a roof. But still...
    - thechao 2y ago
      Jay Leno talks about installing solar on his house (which he did himself) and commenting that he was getting shocked a lot, bc as soon as the PVs are in the sun, they're making electricity. He said it made handling the units tricky.
      - ethbr1 2y ago
        Stupid question I've been curious about. What happens to a PV panel, receiving sunlight, with no load? Does it degrade or suffer ill effects in any meaningful way? Or does it just have a potential between its outputs but otherwise isn't impacted?
        lompad 2y ago
        A small current is going to flow internally, but nothing else happens. It's quite normal to have solar panels running with zero load in regions with lots of PV - reason being, that the carriers need to keep their electricity nets stable and have to carefully balance electricity entering and leaving the net. At least in Germany, every PV installation of certain size (> 30kW peak) is mandated to be able to be shutdown remotely by the carrier if you supply electricity for the net and aren't just using it for yourself. (You get paid the same during shutdowns, just like it were running. Otherwise it would be quite damaging and likely reduce adoption of PV) Point being: no, it doesn't hurt the panels and is a regular ocurence.
        antisthenes 2y ago
        The generated power will be dissipated through the panel as heat, AFAIK. Which means that in winter, probably nothing, because it's cold, but on a hot summer day with peak sun, the heat might start damaging the cells. How much exactly you'd have to look at studies. My guess is the output will permanently degrade by a few % per year if the panel is not connected. Might go down to 80% way quicker than normal (25-yr)
        addaon 2y ago
        > The generated power will be dissipated through the panel as heat, AFAIK. Solar panels are not constant-power devices. In an open circuit, they will generate their open circuit voltage at nearly zero current (except minor internal leakage), and thus nearly zero power. In a short circuit, they will generate nearly zero voltage, and thus also nearly zero power. To get maximum power out of a solar panel requires maximum power-point tracking (MPPT), where the load is adjusted such that the product of voltage and current (that is, power) is optimized for the current conditions; while significant power can be delivered to a fixed load, there's no real power being generated without a load.
    - roughly 2y ago
      > The currents and voltages involved are going to make that a non-starter. Do you really want random people messing with those? As part of our daily lives, a great many of us climb into a steel box powered by explosions and packing a 20 gallon container of flammable liquids (and increasingly several hundred pounds of also flammable batteries containing more electricity than an average family uses in a week) and then pilot that box at 80Mph down a strip of concrete packed with other large high-speed objects containing flammable liquids. Occasionally, we run low on flammable liquids in our high-speed metal box and get to refill the flammable liquid container ourselves at a flammable liquids depot, which contains upwards of 40,000 gallons of the flammable liquid delivered by other larger high-speed metal boxes which also share the same strip of concrete with us. So: I'd expect some product safety iteration here before we get to the "roll out your own solar panels", but no, I don't consider that a non-starter.
      - szvsw 2y ago
        To be fair, it didn’t start that way and there are decades of design, legislation and safety regulations around all this, along with infrastructure for licensing/certifying capabilities, tracking and policing capabilities and mistakes over time, insurance, yada yada. It’s not like that stuff springs up overnight!
      - exe34 2y ago
        the safety of these steel boxes were bought with blood over a hundred years. and the end user doesn't just cut as much as they need and nail it down - the things are practically disposable appliances at this point.
      - lompad 2y ago
        But you can see fuel. You can't see currents and it's not trivially visible which things you can touch at all, which things you can touch at the same time, which protection to wear, how to deal with the potentially fatal flashing arcs, ... PV installations on roofs typically have around 10-20kW peak output. Let's go with 10kW. That's around 25 panels, each outputting 30V with something like 13A. Small installations are typically single-stringed, so you end up with a voltage of 25*30V=750V with 13A DC. That's pretty likely to kill you within milliseconds if you mess up. There's a reason that stuff tends to be handled by professionals. It's a ridiculous (and pointless) risk if you aren't well educated about it and have some experience.
    - malfist 2y ago
      Homeowners work with 240v and tens of amps all the time across the country. Hell I wired a hot tub breaker panel and a car charger. Safe enough interlocks and it's a non issue
      - lompad 2y ago
        And houses are burning and people are being electrocuted regularly - being not only a hazard for themselves but also their entire neighbourhood. I certainly wouldn't want to live next to somebody who thinks they can handle their electricity installation by themselves.
        malfist 2y ago
        I doubt running a circuit for a hot tub is endangering the entire neighborhood
      - quickthrowman 2y ago
        I would rather be zapped with a 240v AC current vs 240v DC current. AC power crosses the zero line twice per cycle while DC does not. AC has a lower ‘let-go’ threshold, but DC contracts your muscles and makes it harder to let go. You are correct though, if you de-energize your panelboard and have a deadfront cover over the line side conductors and lugs, working inside a panelboard (or on electrical wiring) is safe.
        lompad 2y ago
        DC interferes with your heart's rhythm much, much less though, due to being constant. AC's frequency easily causes ventricular fibrillations even at low currents and voltages. AC is considered potentially lethal starting at 50V. For DC it's 120V, because it's significantly easier on your heart.
        bradknowles 2y ago
        It’s the amperage that kills you, not the voltage. 5000VAC at a 1.0 nano amps is not going to be something you can feel, not even as something like static electricity.
    - ben_w 2y ago
      I'm in Germany, our local discount retailers sell PV for apartment balconies as DIY systems — "Plug and play", even. If Lidl can do it, why can't Walmart? https://www.lidl.de/p/vale-balkonkraftwerk-minipv-800-et8-l-830-wp-full-black-2x-415-w-solarmodul/p100377336 https://www.lidl.de/p/vale-balkonkraftwerk-minipv-800-et8-l-...
      - lompad 2y ago
        They're limited to pretty small sizes by german law - they are so insignificant that they're much less dangerous to handle. I'm not up to date on their ROI, but IIR they usually were a rather bad investment and more of a novel toy than a serious and reliable source of electricity. Essentially, any notable installation fundamentally deals with much higher currents and voltages and as such is much, much more dangerous. Once a certain size is reached, the carrier also has to be involved and professional installation is mandatory, both due to the law and requirements by insurance companies. At least here in germany. I've been involved with building all kinds of PV installations in bavaria, from 4kwp up to 20MWp. The balkony generators aren't taken seriously by anybody in the industry right now, at least.
        ben_w 2y ago
        > At least here in germany. I've been involved with building all kinds of PV installations in bavaria, from 4kwp up to 20MWp. The balkony generators aren't taken seriously by anybody in the industry right now, at least. If you're working at that size, I'd expect you to ignore balcony systems regardless of how cost-effective they were. My point here is simply and only that it's possible to make a system safe enough that an untrained and unskilled member of the general public can just plug it in and use it, which is exactly what was being called for up-thread with this: > We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves. Germany basically has that (even if it's not in the form of a roll); there's nothing fundamental preventing the USA from having it too.
      - dzhiurgis 2y ago
        This is 1/10th of what my house needs (and I'm not living outrageously AND far closer to equator than Germany)
    - forgetfreeman 2y ago
      Friendly Neighborhood Handyman checking in here. Average Home Depot customer? Absolutely not unless there's some plan to quadruple suburban emergency services budgets. On the other hand I get pretty tired of sneaking around local restrictions on electrical work. Residential electrical work isn't exactly complex and I can't devote a couple years to working as someone else's laborer to get a cert. I'm perfectly capable of handling 100% of a residential solar install (including battery backup) and it's aggravating af to have to go find an electrician to bribe to get permits and inspections.
      - throwaway173738 2y ago
        Around here you can buy a permit if you’re a homeowner. You then have to set up the inspections and actually do all the work properly, but there are no restrictions like that. The inspecting agency publishes documentation about what to read and common pitfalls even.
        bcrosby95 2y ago
        Yes, this post seems to be by someone who wants to be paid to do this by a home owner. It's very common to need licensing to do something commercially but not when doing it for yourself.
        forgetfreeman 2y ago
        I see how you'd think that but it isn't the case. Where I live only licensed electricians are allowed to do any work more involved than changing a light fixture. As an example I've got a 1600 square foot detached shop on property I recently purchased. There isn't six inches of wiring in the entire building that is up to code. My options are ignore it and risk a fire or electrocution, spend >$15,000 to get the building rewired, or spend $3,000 on materials and risk a life-altering fine and/or jailtime if I get caught fixing it myself. I'd be satisfied if I could simply sit the licensure exam and maybe have to pay extra to do some kind of practical demonstration. Local requirements for residential licensure include documented multi-year experience as an electrician's helper before you can even apply to take the exam.
    - logtempo 2y ago
      for an offgrid installation it's feasable to possible to have an idiot proof system. It rise the cost, but I don't see why it would be impossible. I actually saw one at a store (not for roof but anyway).
  - deleted 2y ago
    [deleted]
szvsw 2y ago
Great responses, thank you! How plausible do you think it is that perovskite cells will see commercial adoption in the next 5 years? This [1] makes it seem like it is possible we will see the first roll out in 2025 but with significant uncertainty about our ability to scale up mfg after that. [1] https://spectrum.ieee.org/amp/perovskite-2667580324-2667580324 https://spectrum.ieee.org/amp/perovskite-2667580324-26675803...
epolanski 2y ago
Can't but feel perovskite to be a fad no different than DSSCs before. And I say it as someone who's researched them at EPFL in Michael Graetzel's laboratory. I don't think the technology will ever be efficient and most importantly stable as needed.
- nick7376182 2y ago
  Does it degrade when hermetically sealed? I thought it was down to moisture and getting it in a double glass would be good enough
  - epolanski 2y ago
    Moisture heat and light all tend to degrade perovskite. Perovskite is a family a materials by the way so many of these issues can be sortened out. I'm overall just skeptic.
    - hn_throwaway_99 2y ago
      > ... heat and light all tend to degrade perovskite. Have no knowledge in this field but if your solar panel material degrades in light that would seem to be an insurmountable problem to me.
      - Dylan16807 2y ago
        For "tend to", finding a design that avoids it is surmounting it. Or if you get it slow enough.
      - choilive 2y ago
        Output degrades at about ~1% a year. EOL for a solar panel is typically about 30 years. It will still generate power but if it is a commercial operation then it will likely be in consideration for replacement. I imagine there would be a large secondary market in the future for used but still functional solar panels as utilities and smaller solar farms replace the panels and possibly funneling into the residential market.
lazide 2y ago
Weight of the panels is not a significant portion of installation and labor costs. Square footage (aka surface area) and installation surface challenges are. Roof mounting is expensive. Supporting snow and wind loads is expensive. Reducing dead weight is only going to help a tiny percent, as even if they weighed literally nothing it would not meaningfully change the load calculations.
- szvsw 2y ago
  That’s in a residential/urban context. I would assume (but have no actual idea, just common sense) that weight matters at least somewhat significantly in an industrial/grid scale context, where shipping and labor are for MW scale systems rather than kW scale systems. I’m not sure how important the weight is here, but it seems reasonable to think that it might be more significant than in a residential/urban context. Could also mean less land use, less structural steel, less maintenance for a system of the same capacity, etc.
  - lazide 2y ago
    It isn’t. A 500 watt panel is about 71 lbs, for 27.5 square feet. That’s the typical commercial panel. A little smaller than a normal 4x8 sheet of plywood. Any structure designed to withstand 100 mph winds (typical in mild areas with no hurricanes or strong gusts) needs to be able to handle 25.6 psf - or 704 lbs - per panel just from wind load. Roughly 10x the panels weight. In most of the US, add on snow loads from 20-100psf or more. I’ve installed panels in areas with 150psf design snow loads. In the 150psf snow load area, that meant an additional 4125 lbs for that same 500 watt panel, each. Or about 58 times the weight of the panel. Steep angles (30 degree or more) can allow reducing that, which is a good idea. So for instance in that area if not mounted very steeply, the racking needs to be able to support 71 lbs (panel) + 704 lbs (wind) + 4125 lbs (snow) per panel. Or 2.5 tons, give or take, for each 71 lb panel. The panel is about 1.5% of the weight in that scenario. And that is with no safety factor. Now the roof has already been designed to bear these loads of course - but not as point loads randomly through the roof deck. So whatever anchoring/racking needs to transmit the forces effectively into the roof in a way it can handle without letting water through, and hopefully without making it impossible to maintain the roof either. And if in an area that freezes, without giving areas for ice to form and jack the roof/panels apart. That isn’t trivial.
hn_throwaway_99 2y ago
But even if we reduce installation and labor costs (and as other comments have mentioned, weight may not be the biggest factor here), my understanding is that solar is already the cheapest energy source per kW by a pretty significant margin. The problem with getting it to replace carbon-based fuel sources is all the other issues GP comment mentioned re storage, grid, etc. That said, it's not like one thing is dependent on the other, so good to see efficiency increasing regardless.
- waldothedog 2y ago
  Interesting podcast discussing, among other things, why being cheap on cost/kwh isn’t enough https://podcasts.apple.com/us/podcast/volts/id1548554104?i=1000658797967 https://podcasts.apple.com/us/podcast/volts/id1548554104?i=1...
  - mcbishop 2y ago
    Volts is an awesome podcast for energy-transition enthusiasts.
- oceanplexian 2y ago
  It’s only cheap if the land is free, transmission costs are free, and your power needs are intermittent. None of those are true in reality. The “solar is the cheapest form of energy” is a marketing gimmick. If it were true free market forces would already gone 100% solar because the purpose of energy companies is to make money.
  - hn_throwaway_99 2y ago
    You seem to have misread my comment, or just didn't read the whole thing, because I mostly agree (except for the part about "land is free" - most of the solar costs I've seen take into consideration full installation and financing costs). I said it was cheapest on a pure per kW basis. But exactly for these reasons e.g. the intermittent nature of it we can not currently go 100% solar without storage solutions, infrastructure improvements, etc. Point being it is those areas that will need to be solved (i.e. come down in price) and that marginal improvements in panel efficiency aren't the limiting factor in going to 100% renewables.
moffkalast 2y ago
Seems a bit counterintuitive for panels made out of lead. Being toxic and not very long lasting doesn't seem like the best combination tbh.
contingencies 2y ago
Weight is relatively irrelevant, as long as people can lift them within health and safety regulations. For shipping in container ships or on trucks, at this order of density magnitude, it's ~free. Re. "Installation and labor" ... many issues here from a western context are likely safety/regulatory driven and not technically driven. In any event, weight reductions are meaningless if you aren't allowed to install it on the roof, or if the first gust of wind breaks it in half because it's acting like a sail. In many cases likely the mounting/frame weighs more than the panel. Macro-demographically, with more people moving in to apartments globally, the residential roof thing is more a temporary western thing than a utility scale solution to global residential macro energy needs. The Chinese know this better than anyone. The true economics of industrial processes are rarely clear to consumers.
deleted 2y ago
[deleted]
elric 2y ago
Weight reductions? Really? Can you elaborate on why that would help? Every PV installation I've seen uses heavy blocks of concrete to keep the panels from taking flight in the wind. The panels themselves are already very light.
webninja 2y ago
Weight might still have a place such as states and countries with hurricanes, tornados, and other windy storms

Denvercoder9 2y ago

How much of that cost is related to the physical handling of the panels themselves, and not the electrical installation, though? Weight reduction isn't going to help there.

mensetmanusman 2y ago
It’s propagates through the supply chain, loading, logistics, wear on vehicle transport etc. We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves.
- deleted 2y ago
  [deleted]
- lompad 2y ago
  The currents and voltages involved are going to make that a non-starter. Do you really want random people messing with those? The solar inverters are also sized that big for a reason. At least in countries with strong regulations around working with electricity this is simply not going to be feasible. I've been in the PV business for some time now and seen a person get killed by it. It's not pretty. Still remembering that smell of burnt flesh... Now, to be fair, that was at a 12MW-installation, not on a roof. But still...
  - thechao 2y ago
    Jay Leno talks about installing solar on his house (which he did himself) and commenting that he was getting shocked a lot, bc as soon as the PVs are in the sun, they're making electricity. He said it made handling the units tricky.
    - ethbr1 2y ago
      Stupid question I've been curious about. What happens to a PV panel, receiving sunlight, with no load? Does it degrade or suffer ill effects in any meaningful way? Or does it just have a potential between its outputs but otherwise isn't impacted?
      - lompad 2y ago
        A small current is going to flow internally, but nothing else happens. It's quite normal to have solar panels running with zero load in regions with lots of PV - reason being, that the carriers need to keep their electricity nets stable and have to carefully balance electricity entering and leaving the net. At least in Germany, every PV installation of certain size (> 30kW peak) is mandated to be able to be shutdown remotely by the carrier if you supply electricity for the net and aren't just using it for yourself. (You get paid the same during shutdowns, just like it were running. Otherwise it would be quite damaging and likely reduce adoption of PV) Point being: no, it doesn't hurt the panels and is a regular ocurence.
      - antisthenes 2y ago
        The generated power will be dissipated through the panel as heat, AFAIK. Which means that in winter, probably nothing, because it's cold, but on a hot summer day with peak sun, the heat might start damaging the cells. How much exactly you'd have to look at studies. My guess is the output will permanently degrade by a few % per year if the panel is not connected. Might go down to 80% way quicker than normal (25-yr)
        addaon 2y ago
        > The generated power will be dissipated through the panel as heat, AFAIK. Solar panels are not constant-power devices. In an open circuit, they will generate their open circuit voltage at nearly zero current (except minor internal leakage), and thus nearly zero power. In a short circuit, they will generate nearly zero voltage, and thus also nearly zero power. To get maximum power out of a solar panel requires maximum power-point tracking (MPPT), where the load is adjusted such that the product of voltage and current (that is, power) is optimized for the current conditions; while significant power can be delivered to a fixed load, there's no real power being generated without a load.
  - roughly 2y ago
    > The currents and voltages involved are going to make that a non-starter. Do you really want random people messing with those? As part of our daily lives, a great many of us climb into a steel box powered by explosions and packing a 20 gallon container of flammable liquids (and increasingly several hundred pounds of also flammable batteries containing more electricity than an average family uses in a week) and then pilot that box at 80Mph down a strip of concrete packed with other large high-speed objects containing flammable liquids. Occasionally, we run low on flammable liquids in our high-speed metal box and get to refill the flammable liquid container ourselves at a flammable liquids depot, which contains upwards of 40,000 gallons of the flammable liquid delivered by other larger high-speed metal boxes which also share the same strip of concrete with us. So: I'd expect some product safety iteration here before we get to the "roll out your own solar panels", but no, I don't consider that a non-starter.
    - szvsw 2y ago
      To be fair, it didn’t start that way and there are decades of design, legislation and safety regulations around all this, along with infrastructure for licensing/certifying capabilities, tracking and policing capabilities and mistakes over time, insurance, yada yada. It’s not like that stuff springs up overnight!
    - exe34 2y ago
      the safety of these steel boxes were bought with blood over a hundred years. and the end user doesn't just cut as much as they need and nail it down - the things are practically disposable appliances at this point.
    - lompad 2y ago
      But you can see fuel. You can't see currents and it's not trivially visible which things you can touch at all, which things you can touch at the same time, which protection to wear, how to deal with the potentially fatal flashing arcs, ... PV installations on roofs typically have around 10-20kW peak output. Let's go with 10kW. That's around 25 panels, each outputting 30V with something like 13A. Small installations are typically single-stringed, so you end up with a voltage of 25*30V=750V with 13A DC. That's pretty likely to kill you within milliseconds if you mess up. There's a reason that stuff tends to be handled by professionals. It's a ridiculous (and pointless) risk if you aren't well educated about it and have some experience.
  - malfist 2y ago
    Homeowners work with 240v and tens of amps all the time across the country. Hell I wired a hot tub breaker panel and a car charger. Safe enough interlocks and it's a non issue
    - lompad 2y ago
      And houses are burning and people are being electrocuted regularly - being not only a hazard for themselves but also their entire neighbourhood. I certainly wouldn't want to live next to somebody who thinks they can handle their electricity installation by themselves.
      - malfist 2y ago
        I doubt running a circuit for a hot tub is endangering the entire neighborhood
    - quickthrowman 2y ago
      I would rather be zapped with a 240v AC current vs 240v DC current. AC power crosses the zero line twice per cycle while DC does not. AC has a lower ‘let-go’ threshold, but DC contracts your muscles and makes it harder to let go. You are correct though, if you de-energize your panelboard and have a deadfront cover over the line side conductors and lugs, working inside a panelboard (or on electrical wiring) is safe.
      - lompad 2y ago
        DC interferes with your heart's rhythm much, much less though, due to being constant. AC's frequency easily causes ventricular fibrillations even at low currents and voltages. AC is considered potentially lethal starting at 50V. For DC it's 120V, because it's significantly easier on your heart.
        bradknowles 2y ago
        It’s the amperage that kills you, not the voltage. 5000VAC at a 1.0 nano amps is not going to be something you can feel, not even as something like static electricity.
  - ben_w 2y ago
    I'm in Germany, our local discount retailers sell PV for apartment balconies as DIY systems — "Plug and play", even. If Lidl can do it, why can't Walmart? https://www.lidl.de/p/vale-balkonkraftwerk-minipv-800-et8-l-830-wp-full-black-2x-415-w-solarmodul/p100377336 https://www.lidl.de/p/vale-balkonkraftwerk-minipv-800-et8-l-...
    - lompad 2y ago
      They're limited to pretty small sizes by german law - they are so insignificant that they're much less dangerous to handle. I'm not up to date on their ROI, but IIR they usually were a rather bad investment and more of a novel toy than a serious and reliable source of electricity. Essentially, any notable installation fundamentally deals with much higher currents and voltages and as such is much, much more dangerous. Once a certain size is reached, the carrier also has to be involved and professional installation is mandatory, both due to the law and requirements by insurance companies. At least here in germany. I've been involved with building all kinds of PV installations in bavaria, from 4kwp up to 20MWp. The balkony generators aren't taken seriously by anybody in the industry right now, at least.
      - ben_w 2y ago
        > At least here in germany. I've been involved with building all kinds of PV installations in bavaria, from 4kwp up to 20MWp. The balkony generators aren't taken seriously by anybody in the industry right now, at least. If you're working at that size, I'd expect you to ignore balcony systems regardless of how cost-effective they were. My point here is simply and only that it's possible to make a system safe enough that an untrained and unskilled member of the general public can just plug it in and use it, which is exactly what was being called for up-thread with this: > We should practically get to the point where someone can buy a roll of material at Home Depot and unravel it on their roof, nail it, and plug it in themselves. Germany basically has that (even if it's not in the form of a roll); there's nothing fundamental preventing the USA from having it too.
    - dzhiurgis 2y ago
      This is 1/10th of what my house needs (and I'm not living outrageously AND far closer to equator than Germany)
  - forgetfreeman 2y ago
    Friendly Neighborhood Handyman checking in here. Average Home Depot customer? Absolutely not unless there's some plan to quadruple suburban emergency services budgets. On the other hand I get pretty tired of sneaking around local restrictions on electrical work. Residential electrical work isn't exactly complex and I can't devote a couple years to working as someone else's laborer to get a cert. I'm perfectly capable of handling 100% of a residential solar install (including battery backup) and it's aggravating af to have to go find an electrician to bribe to get permits and inspections.
    - throwaway173738 2y ago
      Around here you can buy a permit if you’re a homeowner. You then have to set up the inspections and actually do all the work properly, but there are no restrictions like that. The inspecting agency publishes documentation about what to read and common pitfalls even.
      - bcrosby95 2y ago
        Yes, this post seems to be by someone who wants to be paid to do this by a home owner. It's very common to need licensing to do something commercially but not when doing it for yourself.
        forgetfreeman 2y ago
        I see how you'd think that but it isn't the case. Where I live only licensed electricians are allowed to do any work more involved than changing a light fixture. As an example I've got a 1600 square foot detached shop on property I recently purchased. There isn't six inches of wiring in the entire building that is up to code. My options are ignore it and risk a fire or electrocution, spend >$15,000 to get the building rewired, or spend $3,000 on materials and risk a life-altering fine and/or jailtime if I get caught fixing it myself. I'd be satisfied if I could simply sit the licensure exam and maybe have to pay extra to do some kind of practical demonstration. Local requirements for residential licensure include documented multi-year experience as an electrician's helper before you can even apply to take the exam.
  - logtempo 2y ago
    for an offgrid installation it's feasable to possible to have an idiot proof system. It rise the cost, but I don't see why it would be impossible. I actually saw one at a store (not for roof but anyway).
- deleted 2y ago
  [deleted]

szvsw 2y ago

Great responses, thank you! How plausible do you think it is that perovskite cells will see commercial adoption in the next 5 years? This [1] makes it seem like it is possible we will see the first roll out in 2025 but with significant uncertainty about our ability to scale up mfg after that. [1] https://spectrum.ieee.org/amp/perovskite-2667580324-2667580324 https://spectrum.ieee.org/amp/perovskite-2667580324-26675803...

epolanski 2y ago

Can't but feel perovskite to be a fad no different than DSSCs before. And I say it as someone who's researched them at EPFL in Michael Graetzel's laboratory. I don't think the technology will ever be efficient and most importantly stable as needed.

nick7376182 2y ago
Does it degrade when hermetically sealed? I thought it was down to moisture and getting it in a double glass would be good enough
- epolanski 2y ago
  Moisture heat and light all tend to degrade perovskite. Perovskite is a family a materials by the way so many of these issues can be sortened out. I'm overall just skeptic.
  - hn_throwaway_99 2y ago
    > ... heat and light all tend to degrade perovskite. Have no knowledge in this field but if your solar panel material degrades in light that would seem to be an insurmountable problem to me.
    - Dylan16807 2y ago
      For "tend to", finding a design that avoids it is surmounting it. Or if you get it slow enough.
    - choilive 2y ago
      Output degrades at about ~1% a year. EOL for a solar panel is typically about 30 years. It will still generate power but if it is a commercial operation then it will likely be in consideration for replacement. I imagine there would be a large secondary market in the future for used but still functional solar panels as utilities and smaller solar farms replace the panels and possibly funneling into the residential market.

lazide 2y ago

Weight of the panels is not a significant portion of installation and labor costs. Square footage (aka surface area) and installation surface challenges are. Roof mounting is expensive. Supporting snow and wind loads is expensive. Reducing dead weight is only going to help a tiny percent, as even if they weighed literally nothing it would not meaningfully change the load calculations.

szvsw 2y ago
That’s in a residential/urban context. I would assume (but have no actual idea, just common sense) that weight matters at least somewhat significantly in an industrial/grid scale context, where shipping and labor are for MW scale systems rather than kW scale systems. I’m not sure how important the weight is here, but it seems reasonable to think that it might be more significant than in a residential/urban context. Could also mean less land use, less structural steel, less maintenance for a system of the same capacity, etc.
- lazide 2y ago
  It isn’t. A 500 watt panel is about 71 lbs, for 27.5 square feet. That’s the typical commercial panel. A little smaller than a normal 4x8 sheet of plywood. Any structure designed to withstand 100 mph winds (typical in mild areas with no hurricanes or strong gusts) needs to be able to handle 25.6 psf - or 704 lbs - per panel just from wind load. Roughly 10x the panels weight. In most of the US, add on snow loads from 20-100psf or more. I’ve installed panels in areas with 150psf design snow loads. In the 150psf snow load area, that meant an additional 4125 lbs for that same 500 watt panel, each. Or about 58 times the weight of the panel. Steep angles (30 degree or more) can allow reducing that, which is a good idea. So for instance in that area if not mounted very steeply, the racking needs to be able to support 71 lbs (panel) + 704 lbs (wind) + 4125 lbs (snow) per panel. Or 2.5 tons, give or take, for each 71 lb panel. The panel is about 1.5% of the weight in that scenario. And that is with no safety factor. Now the roof has already been designed to bear these loads of course - but not as point loads randomly through the roof deck. So whatever anchoring/racking needs to transmit the forces effectively into the roof in a way it can handle without letting water through, and hopefully without making it impossible to maintain the roof either. And if in an area that freezes, without giving areas for ice to form and jack the roof/panels apart. That isn’t trivial.

hn_throwaway_99 2y ago

But even if we reduce installation and labor costs (and as other comments have mentioned, weight may not be the biggest factor here), my understanding is that solar is already the cheapest energy source per kW by a pretty significant margin. The problem with getting it to replace carbon-based fuel sources is all the other issues GP comment mentioned re storage, grid, etc. That said, it's not like one thing is dependent on the other, so good to see efficiency increasing regardless.

waldothedog 2y ago
Interesting podcast discussing, among other things, why being cheap on cost/kwh isn’t enough https://podcasts.apple.com/us/podcast/volts/id1548554104?i=1000658797967 https://podcasts.apple.com/us/podcast/volts/id1548554104?i=1...
- mcbishop 2y ago
  Volts is an awesome podcast for energy-transition enthusiasts.
oceanplexian 2y ago
It’s only cheap if the land is free, transmission costs are free, and your power needs are intermittent. None of those are true in reality. The “solar is the cheapest form of energy” is a marketing gimmick. If it were true free market forces would already gone 100% solar because the purpose of energy companies is to make money.
- hn_throwaway_99 2y ago
  You seem to have misread my comment, or just didn't read the whole thing, because I mostly agree (except for the part about "land is free" - most of the solar costs I've seen take into consideration full installation and financing costs). I said it was cheapest on a pure per kW basis. But exactly for these reasons e.g. the intermittent nature of it we can not currently go 100% solar without storage solutions, infrastructure improvements, etc. Point being it is those areas that will need to be solved (i.e. come down in price) and that marginal improvements in panel efficiency aren't the limiting factor in going to 100% renewables.

moffkalast 2y ago

Seems a bit counterintuitive for panels made out of lead. Being toxic and not very long lasting doesn't seem like the best combination tbh.

contingencies 2y ago

Weight is relatively irrelevant, as long as people can lift them within health and safety regulations. For shipping in container ships or on trucks, at this order of density magnitude, it's ~free. Re. "Installation and labor" ... many issues here from a western context are likely safety/regulatory driven and not technically driven. In any event, weight reductions are meaningless if you aren't allowed to install it on the roof, or if the first gust of wind breaks it in half because it's acting like a sail. In many cases likely the mounting/frame weighs more than the panel. Macro-demographically, with more people moving in to apartments globally, the residential roof thing is more a temporary western thing than a utility scale solution to global residential macro energy needs. The Chinese know this better than anyone. The true economics of industrial processes are rarely clear to consumers.

deleted 2y ago

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elric 2y ago

Weight reductions? Really? Can you elaborate on why that would help? Every PV installation I've seen uses heavy blocks of concrete to keep the panels from taking flight in the wind. The panels themselves are already very light.

webninja 2y ago

Weight might still have a place such as states and countries with hurricanes, tornados, and other windy storms