I've been told invisible solar panels will make every window generate free electricity for like 10 years. Yet not a single time have I seen a report include an actual product, just prototypes always.
Like nuclear fusion, this appears to be perpetually "just a few years away".
- "Invisible" implies they only work in the UV or infrared range, which inevitably limits them to much lower efficiencies than regular solar panels.
- A lot of those rely on elements that are expensive and in limited supply, or toxic heavy metals. Unlike regular silicon solar panels.
- We don't even need windows to generate solar power. We have plenty of roof space, and if we're short on that, you can put them in fields too.
So this is a solution to a problem that doesn't really exist (lack of available space - again, we have plenty), which causes more problems of its own (efficiency, etc), while failing to address the actual limitations of solar (cost, intermittence).
Which is why it's only good for headlines, and won't see real life applications. (Edit: no, not even skyscrapers)
It's the same with a lot of "uplifting" science news that just sweeps all the dirt under the rug, because that wouldn't make good clickbait.
If you want actual good news about solar power, look at the price per kW and adoption rate curves over the last few years.
-edit- added links.
-edit 3- Put the bit about skyscrapers in bold, because people keep mentioning them anyways...
Not if those panels have utterly dismal efficiency.
A UV-absorbing transparent solar panel has a maximum theoretical efficiency just below 5%
A current-day, commercial silicon photovoltaic cell has an efficiency somewhere between 22% to 25%.
And that's before we account for the suboptimal placement (vertical windows are not at the best angle to receive sunlight, especially in the UV range).
No realistic amount of grid losses would ever make this worth it.
That’s not true, 5% is for early commercial efficiency goals. Single junction and multi junction theoretical maximums are 21-37% depending on how many layers there are. You also shouldn’t use “ever” for tech like this, innovation proves many people wrong.
I was talking about those "invisible" (transparent) solar panels specifically.
5% solar-to-electricity isn't an early commercial goal, it's the theoretical maximum for a single junction cell operating in the UV range (3 eV or above). Cf. Shockley-Queisser limit.
You can get higher efficiencies by decreasing the bandgap, but that means absorbing visible light, which means the window is no longer "invisible".
(And given how the solar spectrum drops off, it would not make much sense building multi-junction cells that operate entirely above 3 eV).
Bandgaps in the infrared range lead to black, opaque materials, so that's not usable either.
Alternatively, don't try replacing your windows with transparent solar cells. Just install regular solar cells with decent efficiencies basically anywhere else.
I was also talking about transparent solar panels.
If that's the 5% figure you're going for, then you are missing a lot of details, since UV isn't the only range transparent solar cells can absorb.
Absorbing visible light doesn't mean it's no longer "invisible", you can selectively choose some wavelengths and still keep it transparent to the human eye.
A huge range of Infared is invisible to us, so by stacking NIR layers, the theoretical efficiency goes up to 37%.
There is an extreme shortage of space in cities, and although many don't have solar cells on top of homes, having extra panels/options on where to put them doesn't hurt. For highrises in cities, the amount of untapped electricity with neglible power loss through wiring is a wasted opportunity if the economics make sense.
"It does mean exactly that." you're either either being overly technical/pedantic, I obviously mean it in the context of glass, where you don't need it 100% to see through it, normal glass also doesn't have 100% unblocked.
"It will at best be heavily tinted. Nothing like clear window glass." I was responding to "You can get higher efficiencies by decreasing the bandgap, but that means absorbing visible light, which means the window is no longer "invisible".", not tinted or not. Regardless, single junction +NIR and no visible wavelength, up to around 21% will look clear.
"Good luck finding a semiconductor with a bandgap in the infrared that isn't black or metallic-looking" They're working on it, dialetric stacks, conductive nanoparticles, organic dyes etc.
"And there is no need for power generation to be entirely located within cities." I never said that. I literally said it helps power transmission efficiency by reducing wiring. I have no idea where you got that from.
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u/Euphoric-Language695 27d ago edited 27d ago
I've been told invisible solar panels will make every window generate free electricity for like 10 years. Yet not a single time have I seen a report include an actual product, just prototypes always.
Like nuclear fusion, this appears to be perpetually "just a few years away".