[HN Gopher] New materials could deliver ultrathin solar panels
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       New materials could deliver ultrathin solar panels
        
       Author : stareatgoats
       Score  : 52 points
       Date   : 2022-01-01 14:16 UTC (8 hours ago)
        
 (HTM) web link (news.stanford.edu)
 (TXT) w3m dump (news.stanford.edu)
        
       | LightG wrote:
       | This is good, but shouldn't the priority maximising power output
       | from X area of solar panel?
       | 
       | I would have thought the industry needs customers to get excited
       | about covering their electricity bills (especially now), let
       | alone just getting to a point where residential customers can
       | enjoy a day of full power without dipping into the grid.
       | 
       | (It's likely I don't know what I'm talking about with the above,
       | but I know what I feel as a potential solar power customer. I
       | imagine this is addressing a different problem that others are
       | interested in, but I wish the industry would solve the most
       | pressing problem).
        
       | jacquesm wrote:
       | Another entry in this already very long list:
       | 
       | https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
        
         | tibyat wrote:
        
       | labawi wrote:
       | Thin/flexible cells are often called "eco", because "less
       | material", but then I find the composition and they are made of
       | Arsenic, Cadmium or similar toxic non-degradable materials that
       | _will_ end up in the environment.
       | 
       | This one seems actually seems very ecological, or at least not
       | toxic:
       | 
       | > tungsten diselenide and contacts of gold spanned by a layer of
       | conducting graphene that is just a single atom thick
       | 
       | They don't mention Cadmium Sulfide surface layer as seems
       | standard in CIGS. Hope they don't feel the need to add it in the
       | efficiency optimization process.
       | 
       | EDIT: Doing some calculation on CIGS with 700A (70nm) CdS layer
       | [1], 1m2 of solar panel would have about 1m2*70nm*5g/cm3 =
       | 1m2*70e-9m*5e6g/m3 ~ 0.4g of CdS.
       | 
       | [1] https://www.nrel.gov/pv/copper-indium-gallium-diselenide-
       | sol...
        
         | truculent wrote:
         | There was an interesting post shared here recently on low-tech
         | solar panels, which might be able to trade off efficiency for
         | recyclability:
         | 
         | https://solar.lowtechmagazine.com/2021/10/how-to-build-a-low...
        
           | labawi wrote:
           | > The plug was an alloy of zinc and antimony - which we now
           | know is a semiconductor. It was alternately capped by German
           | silver (a nickel, copper, and zinc alloy) and copper on
           | opposite ends.
           | 
           | While the design may be possible to make and repair in
           | artisanal manner, it uses a lot of antimony and any repairs
           | would likely shed more Sb than there is Cd in an entire CIGS
           | panel (though In and Ga may be a concern).
           | 
           | If the design was resource-optimized, it would still have a
           | potent monk-killer (Sb) and then it wouldn't be worth it to
           | recycle all of the panels.
        
       | bluGill wrote:
       | Thin isn't as useful as it sounds. For a few application (drones)
       | light weight is important, and thin probably does mean light
       | weight. However for most solar application a bit of extra
       | thickness is just something you design into your mounting system,
       | and since thicker is stronger (think hail and other weather
       | phenomenons) you typically design panels far thicker than needed
       | to support the cell anyway.
        
         | closetnerd wrote:
         | Transportation at the least. Got a place in the mountains -
         | moving a few panels was a insanely costly and annoying.
        
       | SQL2219 wrote:
       | The new Stanford prototype achieves 5.1 percent power conversion
       | efficiency, but the authors project they could practically reach
       | 27 percent efficiency upon optical and electrical optimizations.
       | That figure would be on par with the best solar panels on the
       | market today, silicon included.
        
         | jacquesm wrote:
         | I'll believe it when I see it. Solar panels and batteries are
         | both subjects that have generated far more in terms of
         | improvements on paper than they delivered in real life.
        
           | sdenton4 wrote:
           | You haven't been paying attention, I suppose. The cost per
           | watt of solar panels continues to drop exponentially, as
           | optimizations continue and production continues to scale up.
           | Breakthrough research announcements like this happen often,
           | and only a handful of such announcements will ever make it to
           | production. But improvements certainly /are/ making it into
           | production, and lowering LCOE steadily.
           | 
           | Here's an example graph, with both solar and battery costs:
           | https://greentechlead.com/renewable-energy/cost-for-
           | onshore-...
           | 
           | And compared to fossil fuels: https://en.wikipedia.org/wiki/L
           | evelized_cost_of_energy#/medi...
           | 
           | (LOTS of people think about renewable prices as they were ten
           | years ago instead of where they are now or where they may be
           | in five years. This means lots of people simply have wrong
           | priors about the relative cost of different energy sources.
           | This is expected: People don't intuitively adapt to
           | exponential change.)
        
             | fooblaster wrote:
             | The graphs you mentioned are about cost per watt, an
             | important metric, but not panle conversion efficiency.
        
             | jacquesm wrote:
             | I've been paying _excellent_ attention, the panel
             | efficiency for the various crystal lattices and layering
             | combinations has hardly moved in the last decade. A little
             | bit here, a little bit there.
             | 
             | Sure the price has come down, but that wasn't what this was
             | about.
             | 
             | Also, I think the tone of your comment could be a lot
             | better than it is.
        
               | sdenton4 wrote:
               | Here's some progression of panel efficiency over time:
               | https://news.energysage.com/solar-panel-efficiency-cost-
               | over...
               | 
               | I would suggest it's a matter of "nothing changes in a
               | year but everything changes in a decade."
               | 
               | Partial apologies for the tone; I'm personally kinda sick
               | of Internet comments crapping on people's work by
               | default.
        
               | jacquesm wrote:
               | The part that matters is that 'run of the mill'
               | monocrystalline solar panels, not exotic ones such as
               | triple junction and other very expensive cells have been
               | roughly steady over the last decade or so at 20% give or
               | take, with their polycrystalline brethren doing a
               | slightly worse.
               | 
               | There are prototypes and special application cells that
               | do _much_ better than that, but they are typically priced
               | in such a way that you would never use them in a regular
               | domestic application. But for a satellite or something
               | else where price isn 't your first consideration (but for
               | instance weight is) they may well make good sense.
               | 
               | FWIW I have been following the renewables scene very
               | closely for two decades, have built a house on solar and
               | wind power in Canada and am in the process of converting
               | a house here in NL to as close to self sufficient as I
               | can make it without rebuilding it from the ground up.
        
           | dogma1138 wrote:
           | To add to that you simply can't escape physics...
           | 
           | A 200W solar panel with 20% conversion efficiency needs a
           | 1000W of solar radiation hitting it to produce that much,
           | most of it would be converted into heat, that's roughly the
           | average for an area just under 1 sq/m in size.
           | 
           | Thermals are a big problem for solar panels and I'm not sure
           | how that would work with thinner panels.
           | 
           | I also don't see how you'll power a drone with solar panels
           | regarding how much they weight the surface area seems not to
           | be sufficient even if the panels would be 80-90% efficient.
        
             | labawi wrote:
             | Panel thickness is not a positive factor for cooling, it's
             | only good for structural support. Unless your panels are
             | tiny, all the heat escapes through the front/back surfaces,
             | thinner being better, though surface treatment and airflow
             | is a bigger factor.
             | 
             | If they meant winged drones - those already exist.
        
             | jacquesm wrote:
             | On the plus side, every little bit that can be exported as
             | electrons does not need to be shed as IR. The problem is
             | that quite a bit of that 1000W incident is not in a part of
             | the spectrum that lends itself readily to conversion to
             | electricity.
        
               | addaon wrote:
               | Couldn't one build a dielectric mirror onto the surface
               | of the panel to selectively reflect those frequencies
               | that aren't converted well, to avoid the thermal load of
               | absorbing them? Is the issue that dielectric mirrors are
               | too fragile?
        
               | jacquesm wrote:
               | No, the problem is that your dielectric mirror would have
               | to be a perfect reflector for one set of wavelengths and
               | a perfect passthrough for the remainder. In practice
               | though it will always be gradients so you'll end up
               | reflecting some of what you want and passing some of what
               | you don't want.
        
               | namibj wrote:
               | They are not too fragile; they can coat them onto the
               | solar cell's surface.
        
       | mrfusion wrote:
       | The best thing about being very thin is that they could be folded
       | up into smaller spaces.
       | 
       | You could unfold 100m of panels from the back of your EV when you
       | park. Or carry enough in your backpack to power your lappy.
        
         | dntrkv wrote:
         | I get your point, but you can already carry enough panels in
         | your backup to power your laptop. I have a 100W folding panel
         | that folds down to about 10x8x2.5" I bought it for $200 about a
         | year back, you can pick it up today for $140.
         | 
         | Crazy how fast prices are dropping.
        
           | cced wrote:
           | Link to model? Any recommendations?
        
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       (page generated 2022-01-01 23:02 UTC)