4 ms·

If weight is the issue, well fine. But they deliver (back of the envelope) 37W per square meter. While conventional panels deliver ~200. So any application th

If weight is the issue, well fine. But they deliver (back of the envelope) 37W per square meter. While conventional panels deliver ~200. So any application that's space-limited, these are not a win. And isn't that, every home installation?

tony_cannistra 4y ago
As they mention in the article though, there are lots of applications that aren't space-limited but are structurally-limited (warehouses) in that they can't support the weight of solar panels without more engineering. I did think it was strange that they obfuscated the W/m^2 statistic by only presenting W/kg and kg/m^2. I suppose focusing on watts per kilogram better aligns with a breakthrough in installations with poor structural support for heavy panels.
- JoeAltmaier 4y ago
  In that case I suggest installing efficient panels in some large installation somewhere else. Like, a power company solar farm miles from your warehouse. <digression> It's such a strange magpie impulse folks have to want solar on their house. Look at my stuff! I'm doing things! From a societal point of view the efficient installation is in bulk, serviceable, unobstructed. A rooftop is comically not these things. </digression>
  - thehappypm 4y ago
    Sure, cut down a forest or buy ready land. Level the land, prepare drainage, and install racks to hold the films. Why do that when a warehouse roof is ready for solar to be deployed?
    - lazide 4y ago
      Or just put it on the parking lot? The efficiency is so low on these, good luck. Covering a corner of the parking lot with standard panels is going to be cheaper and easier than doing the roof using these.
      - throwuwu 4y ago
        Covering a parking lot with anything let alone solar panels that require lots of electrical connections is not a simple job. Think of all the supporting posts and beams, footings that will take up space, wind load considerations, etc.
        lazide 4y ago
        Simpler than doing it on a (low load rating) roof, where you also have to deal with an inability to drive to where you are doing things, have low maximum weight limits, have to worry about water tightness, etc. Even better, if the contractor screws it up, it doesn’t burn the building down or cause massive water damage. Worst case some cars catch on fire. Much cheaper!
  - adgjlsfhk1 4y ago
    The advantage of solar on roofs is that solar doesn't need to be serviced often, and the solar panels actually protect the roof under it and will lower electricity use in the summer by keeping sun off the roof.
    - eldaisfish 4y ago
      The disadvantage being that they add weight to the roof and are a significant source of wind load.
      - JoeAltmaier 4y ago
        And pierce the supposedly waterproof roof (the entire point of a roof). And mounted at whatever angle the roof is built, instead of an optimal angle. And are in the most difficult place for maintenance and cleaning, so those things will be neglected. And you need to replace the roof? Now what?
        r_hoods_ghost 4y ago
        You could run cables down the roof and the outside outside of the wall which not particularly rare. Actually that's the case for one of the aerials on my roof. And piercing roofs isn't exactly uncommon. Aircon vents, chimneys, mountings for aerials etc. The thing with something like this is that it doesn't have to be an optimal solution which instantly solves all our problems, which is what a lot of people seem to demand when it comes to anything which is even vaguely green, it just needs to be cheap and easy and move us away from our reliance on fossil fuels. This, along with traditional solar, hydro, onshore and offshore wind, nuclear etc. all have their place.
        eldaisfish 4y ago
        ressources are not infinite and framing the problem as one of good being the enemy of perfect is disingenuous. Rooftop solar is a terrible idea when compared to the alternative - utility scale solar, installed at the right location, in the right way, with economies of scale; all while achieving everything you mentioned. Rooftop solar has numerous problems, starting with structural considerations, scale, shading, imperfect angles, local grid congestion and so on. Why have everyone waste money on this when we could just install solar farms?
  - kwhitefoot 4y ago
    Great in a sparsely populated country like the US, not so much in Belgium, Netherlands, South East England where such installations end up either on agricultural land or in places where housing is needed.
- Someone 4y ago
  On the other hand, 100g/m² is too low for “simply unroll it on a roof”. A carpet so light will blow away in a storm, worst-case taking (part of) the roof with it (roofs often are fairly weak when pulled upwards or sidewards. That’s why solar panels on roofs sometimes are weighed down: it keeps the net force on the roof more or less downwards, even if the wind exerts an upwards force) What would you use to attach these, and what would that weigh? I see these end up on cars, sailing boats, etc, where I think weight and flexibility matter more, before ending up in high-volume applications. On the plus side, the article doesn’t mention it, but I would guess recyclability for these would be higher because they don’t glue cells to glass.
  - r_hoods_ghost 4y ago
    Since it is fabric presumably you could just stick them down the same way you do with a felted roof. I guess you could even incorporate it into a felt roll.
    - throwuwu 4y ago
      It’ll need to be durable enough to walk on then.
      - JoeAltmaier 4y ago
        Hell, durable enough for hail, gales, a foot of snow and ice. Is this really practical for outdoor use at all? Most of us have really durable roofs, not some paper/plastic felt cover.
struggle2 4y ago
In Germany (and I think in the EU) you have a max. weight for cars of about 3.5T (~7716 pounds). You can drive cars that weight more than that but then your speed is limited to (I think 80-100km/h), you have to pay (more) toll and more importantly you have to get a special drivers license in most cases (cost + time). Camper vans usually get very close to that limit. Even if the van has only 2 sleeping spots. Weight is definitely an issue there and most camper vans sold these days come with a solar installation on the roof. With 100W of solar you can expect some additional autonomy as a camper. 200W is considered more than average solar for small camper vans in the EU. A typical 200W solar panel weights in at around 10-13 kg + maybe 1-3 kg for the additional bracket. 11-16kg is something you would think about. Thats also the reason why flexible panels are already used for some camper vans. They also have the advantage than you can put them on un-even surfaces. The VW Grand California for example can be ordered with a flexible panel at the front side: https://de.wikipedia.org/wiki/VW_California#/media/Datei:VW_Grand_California_600_2.0_TDI_%E2%80%93_f_03072021.jpg https://de.wikipedia.org/wiki/VW_California#/media/Datei:VW_...
- ttoinou 4y ago
  16 kg on 3500 kg is nothing and you definitely need 200W and not 40W
  - Retric 4y ago
    The limit is 3500 kg, if you’re at 3300 kg stock then you only have 200kg to play with when retrofitting. Also it’s 200W/m2 but camper roofs are a lot more than 1 square meter so you just cover a larger percentage of the roof with solar.
    - ajsnigrutin 4y ago
      I'd rather have 5x the power and find a few kilos somewhere else to save. If efficiencies were within a few percents.. sure.. but when we're talking about a factor of 5+, it doesn't seem to be worth it.
      - 4y ago
solardev 4y ago
There's no reason to use these on buildings. But think backpacks, balloons, gliders/drones, fabrics for clothing/canvases/sails/porches...

tony_cannistra 4y ago

As they mention in the article though, there are lots of applications that aren't space-limited but are structurally-limited (warehouses) in that they can't support the weight of solar panels without more engineering. I did think it was strange that they obfuscated the W/m^2 statistic by only presenting W/kg and kg/m^2. I suppose focusing on watts per kilogram better aligns with a breakthrough in installations with poor structural support for heavy panels.

JoeAltmaier 4y ago
In that case I suggest installing efficient panels in some large installation somewhere else. Like, a power company solar farm miles from your warehouse. <digression> It's such a strange magpie impulse folks have to want solar on their house. Look at my stuff! I'm doing things! From a societal point of view the efficient installation is in bulk, serviceable, unobstructed. A rooftop is comically not these things. </digression>
- thehappypm 4y ago
  Sure, cut down a forest or buy ready land. Level the land, prepare drainage, and install racks to hold the films. Why do that when a warehouse roof is ready for solar to be deployed?
  - lazide 4y ago
    Or just put it on the parking lot? The efficiency is so low on these, good luck. Covering a corner of the parking lot with standard panels is going to be cheaper and easier than doing the roof using these.
    - throwuwu 4y ago
      Covering a parking lot with anything let alone solar panels that require lots of electrical connections is not a simple job. Think of all the supporting posts and beams, footings that will take up space, wind load considerations, etc.
      - lazide 4y ago
        Simpler than doing it on a (low load rating) roof, where you also have to deal with an inability to drive to where you are doing things, have low maximum weight limits, have to worry about water tightness, etc. Even better, if the contractor screws it up, it doesn’t burn the building down or cause massive water damage. Worst case some cars catch on fire. Much cheaper!
- adgjlsfhk1 4y ago
  The advantage of solar on roofs is that solar doesn't need to be serviced often, and the solar panels actually protect the roof under it and will lower electricity use in the summer by keeping sun off the roof.
  - eldaisfish 4y ago
    The disadvantage being that they add weight to the roof and are a significant source of wind load.
    - JoeAltmaier 4y ago
      And pierce the supposedly waterproof roof (the entire point of a roof). And mounted at whatever angle the roof is built, instead of an optimal angle. And are in the most difficult place for maintenance and cleaning, so those things will be neglected. And you need to replace the roof? Now what?
      - r_hoods_ghost 4y ago
        You could run cables down the roof and the outside outside of the wall which not particularly rare. Actually that's the case for one of the aerials on my roof. And piercing roofs isn't exactly uncommon. Aircon vents, chimneys, mountings for aerials etc. The thing with something like this is that it doesn't have to be an optimal solution which instantly solves all our problems, which is what a lot of people seem to demand when it comes to anything which is even vaguely green, it just needs to be cheap and easy and move us away from our reliance on fossil fuels. This, along with traditional solar, hydro, onshore and offshore wind, nuclear etc. all have their place.
        eldaisfish 4y ago
        ressources are not infinite and framing the problem as one of good being the enemy of perfect is disingenuous. Rooftop solar is a terrible idea when compared to the alternative - utility scale solar, installed at the right location, in the right way, with economies of scale; all while achieving everything you mentioned. Rooftop solar has numerous problems, starting with structural considerations, scale, shading, imperfect angles, local grid congestion and so on. Why have everyone waste money on this when we could just install solar farms?
- kwhitefoot 4y ago
  Great in a sparsely populated country like the US, not so much in Belgium, Netherlands, South East England where such installations end up either on agricultural land or in places where housing is needed.
Someone 4y ago
On the other hand, 100g/m² is too low for “simply unroll it on a roof”. A carpet so light will blow away in a storm, worst-case taking (part of) the roof with it (roofs often are fairly weak when pulled upwards or sidewards. That’s why solar panels on roofs sometimes are weighed down: it keeps the net force on the roof more or less downwards, even if the wind exerts an upwards force) What would you use to attach these, and what would that weigh? I see these end up on cars, sailing boats, etc, where I think weight and flexibility matter more, before ending up in high-volume applications. On the plus side, the article doesn’t mention it, but I would guess recyclability for these would be higher because they don’t glue cells to glass.
- r_hoods_ghost 4y ago
  Since it is fabric presumably you could just stick them down the same way you do with a felted roof. I guess you could even incorporate it into a felt roll.
  - throwuwu 4y ago
    It’ll need to be durable enough to walk on then.
    - JoeAltmaier 4y ago
      Hell, durable enough for hail, gales, a foot of snow and ice. Is this really practical for outdoor use at all? Most of us have really durable roofs, not some paper/plastic felt cover.

struggle2 4y ago

In Germany (and I think in the EU) you have a max. weight for cars of about 3.5T (~7716 pounds). You can drive cars that weight more than that but then your speed is limited to (I think 80-100km/h), you have to pay (more) toll and more importantly you have to get a special drivers license in most cases (cost + time). Camper vans usually get very close to that limit. Even if the van has only 2 sleeping spots. Weight is definitely an issue there and most camper vans sold these days come with a solar installation on the roof. With 100W of solar you can expect some additional autonomy as a camper. 200W is considered more than average solar for small camper vans in the EU. A typical 200W solar panel weights in at around 10-13 kg + maybe 1-3 kg for the additional bracket. 11-16kg is something you would think about. Thats also the reason why flexible panels are already used for some camper vans. They also have the advantage than you can put them on un-even surfaces. The VW Grand California for example can be ordered with a flexible panel at the front side: https://de.wikipedia.org/wiki/VW_California#/media/Datei:VW_Grand_California_600_2.0_TDI_%E2%80%93_f_03072021.jpg https://de.wikipedia.org/wiki/VW_California#/media/Datei:VW_...

ttoinou 4y ago
16 kg on 3500 kg is nothing and you definitely need 200W and not 40W
- Retric 4y ago
  The limit is 3500 kg, if you’re at 3300 kg stock then you only have 200kg to play with when retrofitting. Also it’s 200W/m2 but camper roofs are a lot more than 1 square meter so you just cover a larger percentage of the roof with solar.
  - ajsnigrutin 4y ago
    I'd rather have 5x the power and find a few kilos somewhere else to save. If efficiencies were within a few percents.. sure.. but when we're talking about a factor of 5+, it doesn't seem to be worth it.
    - 4y ago

solardev 4y ago

There's no reason to use these on buildings. But think backpacks, balloons, gliders/drones, fabrics for clothing/canvases/sails/porches...